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This is to certify that the

thesis entitled

MOVEMENT AND RESPONSE OF POTATO
LEAFHOPPER (Empoasca fabae Harris)
(CICADELLIDAE: HOMOPTERA) TO HOST PLANT

HABITATS IN A DIVERSE APPLE AGROECOSYSTEM
presented by

Melanie Joy Kaeb

has been accepted towards fulﬁllment
of the requirements for

M - S . degree in Jntnmology

mm. ..

lMajor professor

Date 1 May 1998

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MOVEMENT AND RESPONSE OF POTATO LEAFHOPPER (EMPOASCA
FABAE HARRIS) (CICADELLIDAE: HOMOPTERA) TO HOST PLANT
HABITATS IN A DIVERSE APPLE AGROECOSYSTEM
By

Melanie Joy Kaeb

A THESIS
Submitted to
Michigan State University
in partial fulﬁllment of the requirements
for the degree of
MASTER OF SCIENCE
Department of Entomology

1998

ABSTRACT
MOVEMENT AND RESPONSE OF POTATO LEAFHOPPER (EMPOASCA
FABAE HARRIS) (CICADELLIDAE: HOMOPTERA) TO HOST PLANT
HABITATS IN A DIVERSE APPLE AGROECOSYSTEM
By

Melanie Joy Kaeb

The movement of the highly mobile potato leafhopper (Empoasca fabae Harris)
was studied in Michigan apple orchards and the surrounding agroecosystem. Potato
leafhopper trap catch was linked to the habitat structure and seasonal potato leafhopper
population fluctuations in and adjacent to the orchards. An extensive trapping network of
geographically stable yellow sticky boards was used to monitor potato leafhopper. Potato
leafhopper was seasonally present in Michigan orchards and was found in high numbers
in the orchards compared to non-host habitats. The alfalfa, apple, soybean and other
deciduous fruit habitats had the highest potato leafhopper trap catch means. The spatial
distribution of potato leafhopper trap catch closely followed the spatial distribution of

host habitat in the agroecosystem over two years.

ACKNOWLEDGEMENTS

The completion of this work was possible only with the help, support and
guidance of many people. I would first like to thank Dr. Mark Whalon, my major
professor, for his support over the past two years. Thank you for providing me with your
guidance, prayers, technology, ﬁnancial support and an uplifting, Godly work
environment in which to complete this Master’s project.

I would like to thank the Whalon lab for the time and patience that you have spent
helping me with this project. Thank you to Dr. Utami DiCosty and Dr. Michael Bush for
providing valuable on the spot scientific advice and encouragement and to Pat Bills for
the statistical help and ideas. Thank you Andrea Coombs, David Mom-Sanchez and to all
of the undergraduate students who have helped me.

I sincerely appreciate the suggestions, ideas and comments from the members of
my guidance committee, Dr. Doug Landis and Dr. Stuart Gage. I also appreciate the time
and patience that Dr. Manual Colunga-Garcia of the Computational Ecology and
Bioinformatics Laboratory spent helping me with my spatial statistics and mapping.

Thank you to my immediate family and to my extended family for the prayers,
love, support, encouragement and insect collecting over the past 24 years that have made
it possible for me to follow my dreams. I would like to extend a special thank you to my
mother, Luanne Kaeb, for her hard work in reading and editing this thesis multiple times.

This work was carried out and completed by the mercy and grace of God. I
would like to thank God for His mercy and grace and for sending his son to die on the

cross that all might be saved.

iii

TABLE OF CONTENTS

List of Tables ...................................................................................................................... vi
List of Figures ................................................................................................................... vii
CHAPTER 1

Introduction: Literature Review .......................................................................................... l
Empoasca fabae .................................................................................................................. 1
Migration ............................................................................................................................. 2
Damage ................................................................................................................................ 3
Orchards .............................................................................................................................. 4
Potato leafhopper + Apples ................................................................................................. 5
FQPA ................................................................................................................................... 5
Agroecosystem .................................................................................................................... 6
Trapping system .................................................................................................................. 8
Technology .......................................................................................................................... 9
Summary and Conclusions ................................................................................................ 10
References ......................................................................................................................... 1 1
CHAPTER 2

Potato leafhopper (Empoasca fabae Harris) (Cicadellidae: Homoptera) movement in the a
diverse deciduous fruit agroecosystem

Abstract ............................................................................................................................. 17
Introduction ....................................................................................................................... 1 8
Materials and Methods ...................................................................................................... 21
Agroecosystem .................................................................................................................. 21
Traps .................................................................................................................................. 22
Sampling ............................................................................................................................ 22
Analysis ............................................................................................................................. 23
Results and Discussion ...................................................................................................... 23
Data Transformation ......................................................................................................... 23
Within Habitat ................................................................................................................... 24
Between Habitat ................................................................................................................ 24
Conclusions ....................................................................................................................... 26
References ......................................................................................................................... 34
CHAPTER 3

Impact of two alternative management systems on potato leafhopper (Empoasca fabae
Harris) (Cicadellidae: Homoptera) in Michigan Apple Orchards

Abstract ............................................................................................................................. 37
Introduction ....................................................................................................................... 38
Materials and Methods ...................................................................................................... 40
Plots ................................................................................................................................... 40

iv

Treatments ......................................................................................................................... 40

Traps .................................................................................................................................. 41
Sampling ............................................................................................................................ 41
Analysis ............................................................................................................................. 45
Results and Discussion ...................................................................................................... 45
Barrier Treatments ............................................................................................................. 45
Spray Treatments ............................................................................................................... 46
Variety Differences ........................................................................................................... 47
Habitat Differences ........................................................................................................... 48
Conclusions ....................................................................................................................... 54
References ......................................................................................................................... 56
CHAPTER 4

Mapping potato leafhopper (Empoasca fabae Harris) (Cicadellidae: Homoptera)
movement in the a diverse deciduous fruit agroecosystem using GIS

Abstract ............................................................................................................................. 58
Introduction ....................................................................................................................... 59
Materials and Methods ...................................................................................................... 62
Agroecosystem .................................................................................................................. 62
Traps .................................................................................................................................. 62
Sampling ............................................................................................................................ 63
Analysis ............................................................................................................................. 63
Spatial Analysis ................................................................................................................. 64
Results and Discussion ...................................................................................................... 67
Spatial Distribution ........................................................................................................... 67
Habitats .............................................................................................................................. 68
Population Movement ....................................................................................................... 74
Conclusions ....................................................................................................................... 77
References ......................................................................................................................... 79
APPENDIX A ................................................................................................................... 82
APPENDD( B ................................................................................................................... 84
APPENDD( C ................................................................................................................... 87

LIST OF TABLES

Table 2.2. Potato leaﬂiopper trap catch mean :1: SEM for all sample dates and selected
habitats, 1996. ....................................................................................................... 31

Table 2.3. Potato leafhopper trap catch mean :1: SEM for all sample dates and selected
habitats, 1997. ....................................................................................................... 32

Table 3.1. Potato Leaﬂiopper (PLH), Empoasca fabae (Harris), trap count means
in a replicated IPM apple orchard system related to surrounding habitat, 1996. .. 52

Table 3.2. Potato Leafhopper (PLH), Empoasca fabae (Harris), trap count means
in a replicated IPM apple orchard system related to surrounding habitat, 1997... 53

Table 2.1. Potato leafhopper trap catch means 1: SEM and F-test p-values for all habitats
in 1996 and 1997. .................................................................................................. 86

Table C. 1. Total potato leaﬂiopper (Empoasca fabae (Harris)) trap catch for each sample
period measured by degree day (base 50F) heat accumulation at the end of the
sample period in the diverse agroecosystem at the Clarksville Horticultural
Experiment Station, 1996. ..................................................................................... 87

Table C.2. Total potato leafhopper (Empoasca fabae (Harris)) trap catch for each sample
period measured by degree day (base 50F) heat accumulation at the end of the
sample period in the diverse agroecosystem at the Clarksville Horticultural
Experiment Station, 1997. ..................................................................................... 91

Table C.3. Total potato leafhopper (Empoasca fabae (Harris)) trap catch for each sample
period measured by degree day (base 50F) heat accumulation at the end of the
sample period in the eight "Alternative Pest Management Systems in Apple"
plots, 1996. ............................................................................................................ 95

Table C.4. Total potato leafhopper (Empoasca fabae (Harris)) trap catch for each sample
period measured by degree day (base 50F) heat accumulation at the end of the
sample period in the eight "Altemative Pest Management Systems in Apple"
plots, 1997. .......................................................................................................... 100

vi

LIST OF FIGURES

Figure 2.3. Taylor’s Power Law regression lines (A) non-transformed means and
variances showing that the data is not normally distributed (B) normally
distributed log (x+1) transformed means and variances. ...................................... 28

Figure 2.4. Mean potato leafhopper trap catches in habitat categories by degree day (base
50F) sample periods in 1996 and 1997, (A) alfalfa, (B) corn, (C) grass ............... 29

Figure 2.4. Continued. Mean potato leafhopper trap catches in habitat categories by
degree day (base 50F) sample periods in 1996 and 1997 (D) orchard, (E)
soybeans, (F) woods. ............................................................................................. 30

Figure 2.5. Means :1: SEM for all habitats, 1996. First year alfalfa (alfalfal) is
signiﬁcantly different (p<0.05; Tukey’s test) from all other habitats. .................. 33

Figure 2.6. Means :1: SEM for all habitats, 1997. Soybeans, alfalfa and apple are
signiﬁcantly different (p<0.05; Tukey’s test) from all other habitats. .................. 33

Figure 3.1. (A) Diagram of an IPM (no barrier) plot, showing the randomly assigned
treatments and variety layouts used in the project. (B) Diagram of a low input
(barrier) plot. ......................................................................................................... 42

Figure 3.2. Placement of the barrier trees surrounding the apple trees in a low input plot.43

Figure 3.3. Layout diagram of the yellow sticky trap stations surrounding the
“Alternative Pest Management Systems in Apple” plots (not to scale). ............... 44

Figure 3.4. Effect of the barrier on the potato leafhopper mean 1 SEM trap catch over
time in 1996 and 1997. (A) There were signiﬁcantly more captured in the barrier
than the no barrier plots in 1996 (P<0.000l ). (B) There were fewer potato
leafhopper captured in the barrier than the no barrier plots in 1997 (P<0.0569). 49

Figure 3.5. Effect of treatment on mean potato leafhopper trap catch over time in 1997.
The mean potato leafhopper trap catch in the check was signiﬁcantly different
(P<0.001) than any of the treatments in the (A) barrier and the (B) no barrier
plots. ..................................................................................................................... 50

Figure 3.6. Effect of variety on the mean potato leafhopper trap catch over time in (A)
1996 and (B) 1997. Overall, there were no signiﬁcant differences between the
different varieties (P<0.05). Liberty showed higher numbers at one sample date
in 1996, but showed lower numbers at the same degree day (base 50F) in 1997. 51

Figure 4.1. Map of yellow sticky trap locations on the Clarksville Horticulture
Experiment Station. Each large rectangle on the maps represents 10 acres. (A)

vii

Computer generated locations from GPS coordinates, (B) Hand drawn locations
from ﬁeld notes. .................................................................................................. 65

Figure 4.2. Potato leafhopper data management stream from the ﬁeld to the ﬁnal GIS
analysis (Gage et. al. 1990). .................................................................................. 66

Figure 4.3. Surface of two—year average trap catch intensity with (A) 1996 vegetation
overlay and (B) 1997 vegetation overlay. ............................................................. 69

Figure 4.4. Trap catch intensity surface maps of the Clarksville Horticultural Experiment
Station with vegetation overlays for (A) 1996 and (B) 1997. ............................. 70

Figure 4.5. Nearest neighbor surface maps of transformed potato leafhopper trap catches
on individual degree day (base 50F) sample dates in (A) 1996 and (B) 1997. ..... 71

Figure 4.6. Surface maps of high vs. low potato leafhopper trap catch surface for 7
selected sample periods in (A) 1996 and (B) 1997. ............................................. 75

Figure 4.7. Potato leafhopper high trap catch surface differences for 6 selected sample
periods in (A) 1996 and (B) 1997. ........................................................................ 76

Figure 2.1. The 1996 map of the Clarksville Horticultural Experiment Station vegetation,
showing the location and physical surroundings of the apple IPM plots. ............. 84

Figure 2.2. The 1997 map of the Clarksville Horticultural Experiment Station vegetation,
showing the location and physical surroundings of the apple IPM plots. ............. 85

viii

CHAPTER 1

Introduction: Literature Review

Empoasca fabae, the potato leaﬂiopper (PLH), is highly polyphagous. It feeds on
over 200 plant hosts (P005 and Wheeler 1943, Lamp et. al. 1994) and is a pest in many
Michigan cropping systems. Potato leafhopper has been documented to cause damage to
alfalfa (Cuperus et. al. 1983), potato (Caneolado and Radcliffe 1979), bean (Roltsch and
Gage 1990), soybean (Poston and Pedigo 1975), and deciduous fruit trees (Schoene
1932). It has also been documented in many non-crop habitats; including, forest, old
ﬁeld, and roadsides (Lamp et. al. 1989). The potato leafhopper can feed on hosts from
most of the major dicotyledonous taxa. It utilizes native and introduced dicot crops,
forages, weeds, shrubs and trees. Monocotyledonous plants, such as grasses and sedges,
are non—hosts. Adult potato leafhoppers are frequently collected on them, and will feed in
no choice tests, but females will not oviposit on non-host monocots (Lamp et. al. 1994).

The potato leafhopper is multivoltine, with three to ﬁve overlapping generations
each year. A female can live up to six months and produce eggs for much of her life span
(DeLong 1938). It is a mobile pest, exhibiting long and short range migration. The short
range, interhabitat migration is active migration that occurs between host plants during
the growing season (Medler 1957, Poston and Pedigo 1975, Lamp et. al. 1994). The long
range migration is an annual passive interstate migration from south to north (Carlson et
al. 1991).

Migration. The potato leafhopper is unable to survive the winter temperatures in

the Midwest (Decker and Maddox 1987) and it disappears each winter when temperatures

fall below survival thresholds. Decker and Cunningham (1968) report that potato
leafhopper overwinter and begin spring reproduction on weedy annual legumes in the
states near the Gulf of Mexico. Taylor and Shields (1995a,b) report the collection of
potato leafhopper in Arkansas and Tennessee in January, and the collection of potato
leafhopper from several Pinus spp. in the overwintering range. They found no evidence
of oviposition on pine, but suggested that pine species serve as transient hosts during the
winter (Taylor et. al. 1993). The number of potato leafhopper available for the northern
spring migration depends on the availability and quality of host plants and the occurrence
of lethal temperatures encountered at the overwintering sites (Berberet and Hutchison
1994).

Potato leafhoppers move north on early season air currents and arrive in Michigan
in mid-May to late June on spring weather systems. Potato leafhopper arrival dates and
corresponding weather patterns have been tracked in the midwestem and eastern states
since 1951 (Maredia et. al. 1998). The exact weather transport conditions needed for
potato leaﬂiopper migration to occur have been determined (Carlson et. al. 1991, 1992).
It is possible to predict potato leafhopper migration and arrival from weather patterns in
the early spring. From 1986 until 1998, the Pesticide Alternatives Lab has conducted a
spring migration detection trapping network. This extended and intense transect system
confirms the potato leafhopper arrival date each year. From this transect data, we
hypothesize that potato leafhoppers begin feeding and reproducing on deciduous trees.
They are the only plants providing enough vegetative growth to support a phloem feeder
when the potato leafhopper arrival occurs (DiCosty et. al. 1998, Kaeb and Whalon 1998).

The appearance of the first Michigan potato leafhopper generation depends on

spring transport events and degree day (base 50°F) heat accumulation following arrival.
The migratory generation is usually not large enough to cause economic damage to crops,
but potato leafhoppers are prolific and the population may quickly rise to damaging
levels if optimum conditions occur. Potato leafhopper development is based on ambient
temperature because the potato leafhopper is poikilothermic (Higley and Peterson 1994).
There are 5 temperature-based potato leafhopper development models found in the
literature (Koukolekas and Decker 1966, Simonet and Pienkowski 1980, Onstad et al.
1984; Hogg 1985, Sher and Shields 1993). There is no correlation between the arrival
date and the subsequent severity of potato leafhopper infestation (Maredia et. al. 1998)

Damage. Potato leafhoppers feed on the phloem tissue of host plants,
puncturing, tearing and distorting the cells in the vascular bundle as they use their
proboscis to empty the cell contents (Ecale and Backus 1995a). As the potato leafhopper
probes into the plant tissue, it secretes a salivary ﬂuid, which hardens into a sheath. This
sheath remains in the plant for a long period of time (Ecale and Backus 1995b). Potato
leafhopper feeding behavior and the resulting residue cause a V-shaped chlorotic area
called ‘hopper burn.’ Hopper burn reduces plant photosynthesis, stunts plant growth and
reduces crop yields (DeLong 1971, Welker 1992).

High numbers of potato leafhopper cause direct economic damage to forage crops
such as alfalfa (Cuperus et. al. 1983). According to Berberet and Hutchison (1994),
potato leaﬂiopper populations as low as 0.3 to 2.0 potato leafhoppers per sweep in plants
<30 cm tall will cause stunting and reduced yields. If 5 to 6 potato leafhoppers per
sweep occur over an extended period (20- to 30—d), the crude protein content of the hay

will be reduced and delayed maturity can limit the number of cuttings in a season. High

numbers of potato leaﬂioppers cause indirect economic damage by foliar feeding to fruit
crops such as apples (Schoene 1932) by reducing photosynthesis in the leaves and
reducing fruit yield.

Orchards. Michigan orchards are very ecologically complex (Whalon and Croft
1985) due to the temporal and spatial architecture of the system. Upon reaching maturity,
fruit bearing deciduous trees produce a crop each year for many years. Trees are
expensive to establish and may take several years to reach fruit bearing age. They are
planted in rows with ground cover between the rows and under the trees. The physical
complexity and the diversity of vegetation found in orchard systems provide many
opportunities for insects and diseases to attack the crop and damage the trees. The impact
of the diverse insect pest complex found in Michigan orchards can be signiﬁcantly
inﬂuenced by disturbance (Wise 1990), nutrient flow (Strickler and Whalon 1985,
Strickler et. al. 1987), and ground cover (Larson and Whalon 1987). This makes orchard
pest management a difficult job. Producers manage tree health for short-term crop
production and long term stability using fertilizers, insecticides, fungicides and integrated
pest management techniques.

Many studies have been done on deciduous fruits and the damage caused by
individual components of the pest complex. None of the studies in the past 50 years
mention potato leafhopper as anything other than an occasional occupant of orchards.
The 1998 Michigan Fruit Spraying Calendar (Jones et. al. 1998) states, as a side note,
“most organophosphates (OPS) applied for other pests will control potato leafhoppers.”
The potato leafhopper has not been a pest in Michigan orchards since OPs came into

wide spread usage in the 19505. Prior to OPS, however, the potato leafhopper was a

serious orchard pest.

Potato leafhopper + Apples. There are many extension reports from the early
1900’s that describe the potato leafhopper as a pest in apple orchards (Garman 1908,
Washbum 1903, Schoene 1932, DeLong 1931). According to Schoene (1932), potato
leafhopper is a serious economic pest of young apple trees and cultivated orchards. Potato
leafhopper damage to apples includes brown leaf margins in moderate infestations,
stunting, reduced vigor, and delayed bearing or even tree death in medium and high
infestations. Schoene and Underhill (1937) published an exhaustive study on the
susceptibility of the (then) commonly grown apple varieties, classifying them as being
low, moderate or highly susceptible. Low susceptibility is correlated to the presence of
heavy pubescence on the apple leaves, similar to susceptibility results in glabrous vs.
pubescent soybeans (Johnson and Hollowell 1935) and glandular hair alfalfa (Sulc et. a1.
1997). There were no further studies of potato leafhopper damage in apples after OPs
came into common orchard use.

FQPA. Rising environmental awareness and new pesticide laws, including the
Food Quality Protection Act of 1996, are threatening Michigan fruit producers with the
loss of OP insecticides (Gray et. al. 1996, Peterson 1998). The intent of FQPA is to
provide a safe food supply, with special emphasis on pesticides in the diets of infants and
children and on the safety of estrogen mimics (Colbom et. al. 1996) in the food supply.
EPA is implementing FQPA by following a “worst-ﬁrst” strategy, reviewing the
registrations of the OPS, carbamates and B2 carcinogens in the ﬁrst three years of the ten
year implementation project. Loss of these pesticides because of reduced tolerances and

canceled registrations will force producers out of business if there are no alternatives in

place to control pest outbreaks.

The “soft,” more pest specific chemicals and tactics being developed to replace
the OPS for control of primary pests do not control secondary non-target pests. The loss
of broad spectrum chemical control exposes other weaknesses in the current orchard
production system. Commonly grown varieties of apple have little resistance to a phloem
damaging pest such as the potato leafhopper. The trees are also grown on dwarf
rootstocks, further lowering resistance. The stage is being set for the re-emergence of an
“old-fashioned” pest, the potato leafhopper.

We face a number of challenges as we transition the Michigan fruit production
system to softer, more environmentally friendly programs of pest control. Broad
spectrum pesticides allowed producers to virtually ignore the effects of surrounding
habitats on the pest complex within the orchard. With the loss of chemical control
options, the impact of the agroecosystem on potato leafhopper/crop interactions becomes
more important.

Agroecosystem. The agroecosystem is the physical landscape of the living and
non living material in an agricultural production area and the interactions between the
components of this landscape (Landis 1994). The size of an agroecosystem is plastic,
depending on the scale of the landscape element being studied. It can be deﬁned as a
field, a group of fields and surrounding habitats, a farm, a township, a county, a region, a
state, or a group of states. In this study, we deﬁne the agroecosystem as the crops, plants,
pests, natural enemies, and interactions on the 380 acres of the Clarksville Horticultural
Experiment Station and the target organism as the potato leafhopper.

Plants do not move once they begin growing, however, plants separated by large

distances can have significant effects on each other due to the mobility of insects and
diseases. Potato leafhopper populations can build up on one plant or group of plants,
when the conditions change, they move to other plants suitable to growth and
development and cause further damage. Host change may be due to long distance
migration (Taylor and Shields 1995), disturbance (Pienkowski and Medler 1962), loss of
nutrients in maturing or stressed hosts (Schoene 1932, Hoffman and Hogg 1992) or
reproduction needs. More plants are suitable for adult survival than for oviposition and
nymph survival due to morphological and chemical characteristics (Lamp et. al. 1984).

Aggregations of potato leafhopper populations occur for several reasons. Host
habitat or close proximity to a host habitat is an indicator of potential potato leafhopper
aggregations within an agroecosystem (Roltsch and Gage 1990,Wise 1990).
Microclimates within a host habitat, such as the topographically elevated portions of the
alfalfa ﬁeld studied by Kieckhefer and Medler (1966), are also potential aggregation
sites.

Plant repellency is another potential potato leafhopper-plant interaction in the
agroecosystem. Mixtures of host and non host plants can reduce the number of potato
leafhoppers feeding and reproducing on the host plant due to the repellent effect of the
non host plant. Roltsch and Gage (1990) demonstrate this reduction in potato leafhopper
numbers using tomato and bean intercropping. Roda et. al. (1997a,b) uses alfalfa —
forage grass mixtures and Lamp (1991) uses alfalfa-oat intercrop systems.

The high mobility, highly phytophagous nature of the potato leafhopper and its
ability to cause serious economic damage in many crops has caused it to be the subject of

many studies. Studies have focused on potato leafhopper interactions within crops (Flinn

et. al. 1986), between crops (Poston and Pedigo 1975), in habitats proximate to crops
(Wise 1990) and between host and non-host crops (Roltsch and Gage 1990). This study
attempts to link potato leaﬂiopper trap catch to interactions with the habitats in the
agroecosystem.

Trapping system. Sampling techniques, such as yellow sticky traps, provide a
relative estimate of the target organism population of the that is not directly related to
land surface area. The technique itself provides the reference for the estimates,
expressing counts as the number of target organisms per trap (Buntin 1994). In pest
management programs, relative trapping techniques provide a cost-efﬁcient technique of
arthropod monitoring. They give direct evidence of the presence and relative population
size of the target organism, are low cost and require minimal labor.

Yellow sticky traps attract and capture potato leafhoppers (Hi gley and Peterson
1994). The yellow color provides a visual stimulus, mimicking the pigments in nitrogen
rich foliage that are attractive to the potato leaﬂiopper. When a potato leafhopper comes
into contact with the board, the sticky substance retains it. Sampling is continuous and
information is gathered about the potato leafhopper population 24 hours a day. The
yellow sticky trap sampling method is dependent not only on the insect density, but on
several other variables. Color attraction, ﬂight behavior, wind speed, and temperature
can affect the number of potato leaﬂioppers collected in a given sample (Wise 1990).

We used an extensive trapping system, limiting the number of traps in each
habitat so many habitats can be sampled over a large geographic area (Buntin 1994). The
sampling objectives were to detect potato leafhopper in a given habitat and to provide

information on the status of potato leafhopper in the habitat.

Technology. The position of each trap was precisely recorded using a handheld
GPS unit. The Global Positioning System (GPS) was developed by the U. S. Department
of Defense to facilitate precise wartime troop movement over unknown terrain. This
defense technology lends itself nicely to use in precision agriculture and research
(Schueller and Stout 1995). The GPS system consists of 24 satellites orbiting the earth at
an altitude of 11,000 miles. The satellites are used as precise reference points by the
handheld GPS unit. From 3 reference points, GPS triangulates location and speed using
distance measurements. Signals from 4 satellites allow the GPS to calculate elevation of
the trap. There is an error factor induced by the Department of Defense into civilian GPS
units which makes GPS only accurate to within 100m. This inaccuracy can be corrected
by using a differential FM signal with the GPS unit to attain coordinates that have within
1 m accuracy (Trimble Navigation 1995).

The GPS data, potato leafhopper sample data and the vegetation data for each
sample date are entered into a relational database. A relational database allows the user
to manipulate large data sets without having to deal with the entire set all of the time.
Each type of data is stored in a separate table. Tables contain similar reference fields that
are used to join related data from separate tables. A query is used to join desired data
from separate tables into a common table, allowing for the efﬁcient manipulation of a
small part of a large data set. The data in these small, speciﬁc tables can be moved out of
the database program and used for statistical analyses, graphing or setting up other tables.

The ﬁnal step in the manipulation process of spatial data is to transfer the data
sets from the relational database into a Geographic Information System (GIS). GIS are

computer-based systems that facilitate the input storage, manipulation and output of geo-

referenced data, allowing users to relate disparate data on the basis of common
geographic location (Morris 1996). In precision agriculture, GIS and GPS are combined
for real-time data collection with accurate position information, and efﬁcient
manipulation and analysis of large amounts of spatial data. Applications of this data are
ﬁeld mapping, soil sampling, crop scouting, parallel swath guidance, variable rate
applications of fertilizer and pesticide, and yield mapping. GIS and GPS have also been
successfully used in entomological research. Michigan gypsy moth populations have
been monitored and mapped for more than 10 years using an extensive geo-referenced
pheromone trap system and GIS (Pijanowski and Gage 1996). Gage et. al. (1990) and
Gage and Pijanowski (1993) used these maps to predict regional gypsy moth trends and
to assess the ecological risk from the pest populations. The potato leafhopper data
gathered in this study is analyzed in a similar manner, in a smaller agroecosystem.
Summary and Conclusions. This potato leafhopper study attempts to link potato
leafhopper trap catch ‘population dynamics’ (Flinn et. al., 1986) during the growing
season to potato leafhopper seasonal population ﬂuctuations and habitat structure
(Pimentel 1961, Smith et. al. 1992) in and adjacent to the deciduous fruit orchards at the
Clarksville Horticultural Experiment Station. Our data is used to gain basic insight into
the short-range movement of potato leafhopper between orchards and the surrounding
habitats by conventional statistics and GIS mapping. The goal of the project was to
assess the difﬁculties associated with the control of a highly mobile pest that has the

potential to re-emerge as a serious pest in many crop systems.

10

References

Berberet R. C. and W. D. Hutchison. 1994. Sampling methods for insect management
in alfalfa, pp. 357-381. In L. P. Pedigo and G. D. Buntin [eds.]. Handbook of
sampling methods for arthropods in agriculture. CRC Press, Boca Raton, Florida.

Buntin, G. D. 1994. Developing a primary sampling program, pp. 99-115. In L. P.
Pedigo and G. D. Buntin [eds.]. Handbook of sampling methods for arthropods in
agriculture. CRC Press, Boca Raton, Florida.

Cancelado, R. E., & E. B. Radcliffe. 1979. Action thresholds for potato leaﬂiopper on
potatoes in Minnesota. J. Econ. Entomol. 72: 566-569.

Carlson, J. D., M. E. Whalon, D. A. Landis, & S. H. Gage. 1992. Springtime weather
patterns coincident with long distance migration of potato leafhopper into

Michigan. Agricultural and Forest Meteorology. Elsevier Science Publishers
B.V., Amsterdam. 59: 183-206.

Carlson, J. D., M. E. Whalon, D. A. Landis, & S. H. Gage. 1991. Evidence for long-
range transport of potato leaﬂiopper into Michigan. Reprinted from the Preprint
Volume of the Tenth Conference on Biometerology and Aerobiology and the
Special Session on Hydrometeorology. September 10-13, 1991. Salt Lake City,
Utah. Published by the American Meteorological Society.

Colburn, T., D. Dumanoski, and J. P. Myers 1996. Our Stolen Future: are we
threatening our fertility, intelligence, and survival?: a scientiﬁc detective story.
Penguin Books USA, Inc. New York. 315p.

Cuperus, G. W., E. B. Radcliffe, D. K. Barnes, & G. C. Marten. 1983. Economic
injury levels and economic thresholds for potato leaﬂiopper (Homoptera:
Cicadellidae) on alfalfa in Minnesota. J. Econ. Ent. 76(6): 1341-1349.

Decker, G. C. & H. B. Cunningham. 1968. Winter survival and overwintering area of
the potato leafhopper. J. Econ. Entomol. 61: 154-161.

Decker, George C. and J. V. Maddox. 1987. Cold-Hardiness of Empoasca fabae and
Some Related Species. J. Econ. Ent. 60: 1641-1645.

DeLong, D. M. 1931. The more important species of leafhoppers affecting the apple. J.
Econ. Ent. 24: 1214-1222.

DeLong, D. M. 1938. Biological studies of the leafhopper Empoascafabae as a bean
pest. USDA Technical Bulletin 618.

DeLong, D. M. 1971. The Bionomics of Leaf hoppers. Ann. Rev. Entomol. 16: 179-210.

11

DiCosty, U. R., M. J. Kaeb and M. E. Whalon. 1998. Characterize and quantify the
long range dispersal of potato leafhopper: Michigan. In Spatial dynamics of
leafhopper pests and their management on alfalfa. Reports prepared for the NC-
193 technical committee. Columbus, OH. March 4-5.

Ecale, C. L., and E. A. Backus. 1995a. Mechanical and salivary aspects of potato
leafhopper probing in alfalfa stems. Entomol. Exp. Appl. 77: 121-132.

Ecale, C. L., and E. A. Backus. 1995b. Time course of anatomical changes to stem
vascular tissues of alfalfa, Medicago sativa, from probing injury by the potato
leafhopper, Empoasca fabae. Can. J. Bot. 73: 288-298.

Flinn, P. W., R. A. J. Taylor, & A. A. Hower. 1986. Predictive model for the
population dynamics of potato leafhopper, Empoasca fabae (Homoptera:
Cicadellidae), on alfalfa. Environ. Entomol. 15: 898-904.

Gage, S. H., T. M. Wirth, and G. A. Simmons. 1990. Predicting regional gypsy moth
(Lymantriidae) population trends in an expanding population using pheromone
trap catch and spatial analysis. Environ. Entomol. 19: 371-377.

Gage, S. H. and B. Pijanowski. 1993. Application of remote sensing and analysis of
digital landscape maps to assess ecological risk from pest populations.
Proceedings, 25th International Symposium, Remote Sensing and Global
Environmental Change. pp. 390-402.

Garman, H. 1908. Apple orchard pests in Kentucky. Ky. Agr. Exp. Sta. Bul. 13321-71.
(page 57)

Gray, J. I., J. Flore, M. Hausbeck, L. Olsen, M. Whalon, C. Harris, J. Johnson, K.
Renner, P. Vergot, and P. Bills. 1996. The assessment of pesticides at risk in the
future of Michigan food and feed plant agriculture: A process. Michigan Agric.
Exp. Stn. Special Report 86. E. Lansing, MI. 15pp.

Higley L. G. and R. K. D. Peterson. 1994. Initiating sampling programs, pp. 119-136.
In L. P. Pedi go and G. D. Buntin [eds.]. Handbook of sampling methods for
arthropods in agriculture. CRC Press, Boca Raton, Florida.

Hoffman, George D. & Hogg, David. 1992. Effect of Alfalfa Water Stress on Potato
Leafhopper (Homoptera: Cicadellidae) Plant Preference and Oviposition Rate.
Ann. Entomol. Soc. Am. 85(4): 506-516

Hogg, D. B., 1985. Potato leafhopper (Homoptera: Cicadellidae) immature development,
life tables and populations dynamics under ﬂuctuation temperatures regimes.
Environ. Entomol. 14: 349-355.

Johnson, H. W. and E. A. Hollowell. 1935. Pubescent and glabrous characters of

soybeans as related to resistance to injury by the potato leaﬂiopper. J our. Agr.
Res. 51:371-381.

Jones, A. L., L. Gut, J. Wise and J. Hull. 1998. Fruit Spraying Calendar 1998: for
commercial fruit growers. Michigan State University. Ext. Bull. E-154.

Kaeb, M. J. and M. E. Whalon. 1998. Michigan: Potato leafhopper trap catch in a
diverse apple agroecosystem. In Spatial dynamics of leafhopper pests and their

management on alfalfa. Reports prepared for the NC-193 technical committee.
Columbus, OH. March 4-5.

Kieckhefer, R. W., and J. T. Medler. 1966. Aggregations of the Potato Leafhopper in
Alfalfa Fields in Wisconsin. Ann. Entomol. Soc. Amer. 59(1): 180-182.

Kouskolekas, C. A., & G. C. Decker. 1966. The effect of temperature on the rate of
development of the potato leafhopper, Empoascafabae (Homoptera: Cicadellidae).
Ann. Entomol. Soc. Am. 50: 294-298.

Lamp, W. 0., M. J. Morris, & Edward J. Armbrust. 1984. Suitability of common
weed species as host plants for the potato leafhopper, Empoascafabae. Entomol.
Exp. Appl. 36: 125-131.

Lamp, W. O., M. J. Morris, & E. J. Armbrust. 1989. Empoasca (Homoptera:
Cicadellidae) abundance and species composition in habitats proximate to alfalfa.
Environ. Entomol. 18: 423-428.

Lamp, W. O. 1991. Reduced Empoasca fabae (Homoptera: Cicadellidae) density in oat-
alfalfa intercrop systems. Environ. Entomol. 20: 118-126.

Lamp, W. 0., G. R. Nielsen, & S. D. Danielson. 1994. Patterns among host plants of

potato leafhopper, Empoascafabae (Homoptera: Cicadellidae). J. Kansas Ent.
Soc. 67(4): 354-368.

Landis, D. A. 1994. Arthropod sampling in agricultural landscapes, pp. 15-31. In L. P.
Pedigo and G. D. Buntin [eds.]. Handbook of sampling methods for arthropods in
agriculture. CRC Press, Boca Raton, Florida.

Larson K. J. and M. E. Whalon. 1987. Crepuscular movement of Paraphlepsius
irroratus (Say)(Homoptera: Cicadellidae) between the groundcover and cherry
trees. Environ. Entomol. 16(5):] 103-1106.

Maredia, K.M., M. E. Whalon, S. H. Gage and M. J. Kaeb. 1998. Observations of
First Occurrence and Severity of potato leafhopper, Empoasca fabae (Harris),

(Homoptera: Cicadellidae) in the North Central and Eastern United States. Great
Lakes Entomol. In Press, Vol. 31, Number 1.

13

Medler, J. T. 1957. Migration of the potato leafhopper - a report on a cooperative
study. J. Econ. Entomol. 50: 495-497.

Morris, S. 1996. Geographic information systems. [Online] Available http://library.
berkeley.edu/UCBGIS/what_is_gis.html, September 22, 1997

Onstad, D. W., C. A. Shoemaker, & B. C. Hansen. 1984. Management of potato
leafhopper, Empoasca fabae (Homoptera: Cicadellidae), on alfalfa with the aid of
systems analysis. Environ. Entomol. 13: 1046-1058.

Peterson, D. 1998. Will food quality protection act ﬁnish off fruit farmers: Half to 90%
of OP-insecticides may be lost by 1999. Michigan Farmer. 302(3): 18.

Pienkowski, R. L., & J. T. Medler. 1966. Potato leafhopper trapping studies to
determine local ﬂight activity. J. Econ. Ent. 59(4): 837-843.

Pienkowski, R. L., & J. T. Medler. 1964. Synoptic weather conditions associated with

long-range movement of the potato leafhopper, Empoasca fabae, into Wisconsin.
Ann. Entomol. Soc. Am., 57: 588-591.

Pienkowski, R. L. & J. T. Medler. 1962. Effects of alfalfa cuttings on the potato
leafhopper, Empoasca fabae. J. Econ. Ent. 55(6): 973-978.

Pijanowski, B. and S. H. Gage. 1996. Case Study 1: GIS Fights the gypsy moth. In
Getting to know geographic inforrnaion systems. Keith Clarke [ed].

Pimentel, D. 1961. The inﬂuence of plant spatial patterns on insect populations. Ann.
Entomol. Soc. Amer. 54:61-69.

Poos, F. W. and N. H. Wheeler. 1943. Studies on the host plants of the leafhoppers of
the genus Empoasca. USDA Tech. Bull. No. 850:1-51.

Poston, F. L., & L. P. Pedigo. 1975. Migration of plant bugs and the potato leafhopper
in a soybean-alfalfa complex. Environ. Entomol. 4: 8-10.

Roda, A. L., D. A. Landis, and J. R. Miller. 1997. Contact-induced emigration of
potato leaﬂ10pper(Homoptera: Cicadellidae) from alfalfa-forage grass mixtures.
Environ. Entomol. 26(4):754-762.

Roda, A. L., D. A. Landis, and M. L. Coggins. 1997. Forage grasses elicit emigration
of adult potato leaﬂiopper (Homoptera: Cicadellidae) from alfalfa-grass mixtures.
Environ. Entomol. 26(4): 745-753.

Roltsch, W. J. & S. H. Gage. 1990. Inﬂuence of bean-tomato intercropping on
population dynamics of the potato leafhopper (Homoptera: Cicadellidae). Environ.

l4

Entomol. 19(3): 534-543.

Roltsch, W. J. & S. H. Gage. 1990. Potato leafhopper (Homoptera: Cicadellidae)
movement, ovipositon, and feeding response patterns in relation to host and
nonhost vegetation. Environ. Entomol. 19(3): 524-533.

Schueller, J. K.; Stout, B. A. 1995. Keynote report: Agricultural trends and their
effects on technological needs for farm equipment in the let century. Club of
Bologna, Proceedings of the 6th Meeting of the Full Members, Bologna, Italy.
November 6-8, pp65-78.
http://www.age.uiuc.edu/classes/age221/precag/jsnews.html

Schoene, W. J. 1932. Leaﬂioppers injurious to apple trees. Va. Agr. Exp. Sta. Bul.
283: 1-34.

Schoene, W. J. and G. W. Underhill. 1937. Resistance of certain varieties of apple

trees to injury by the leafhopper (Empoasca fabae). Va. Agr. Exp. Sta. Tech. Bul.
5921-16.

Sher, R. B. & E. J. Shields. 1991. Potato leaﬂiopper (Homoptera: Cicadellidae)
oviposition and development under cool ﬂuctuating temperatures. Environ.
Entomol. 20(4): 1 1 13-1 120.

Simonet, D. E. & R. L. Pienkowski. 1980. Temperature effect on development and
morphometrics of the potato leafhopper. Environ. Entomol. 9: 798-800.

Smith II, L. M., W. O. Lamp, & E. J. Armbrust. 1992. Potato leafhopper
(Homoptera: Cicadellidae) utilization of alfalfa as a host: the role of non-host
stimuli. J. Entomol. Sci. 27(1): 56-64.

Strickler, K and M. E. Whalon. 1985. Microlepidoptera species composition in
Michigan apple orchards. Environ. Entomol. 14:486-495.

Strickler, K., N. Cushing, M. E. Whalon and B. A. Croft. 1987. Mite (Acari) species
composition in Michigan apple orchards. Environ. Entomol. 16:30-36.

Sulc, R. M., J. S. McCormick, L. H. Rhodes, C. Penrose, and E. Volbom. 1997.
Ohio forage performance trials 1997. Ohio State University Extension, OARDC.
Series 195. December 1997.

Taylor, P. S. & E. J. Shields. 1995. Phenology of Empoascafabae (Harris)
(Homoptera: Cicadellidae) in its overwintering area and proposed seasonal

phenology. Environ. Entomol. 24: 1096-1108.

Taylor, P. S. & E. J. Shields. 1995. Development of migrant source populations of the
potato leafhopper (Homoptera: Cicadellidae). Environ. Entomol. 24: 1115-1121.

15

Taylor, P. S., J. L. Hayes, & E. J. Shields. 1993. Demonstration of pine feeding by
Empoasca fabae (Harris) (Homoptera: Cicadellidae) using an elemental marker. J.
Kansas Entomol. Soc. 66(2): 250-252.

Trimble Navigation, Ltd. 1995. Scout GPS and scoutmaster GPS user manual. Mobile
Computing Products, Sunnyvale, CA.

Washburn, F. L. 1903. Injurious insects of 1903. Minn. Agr. Exp. Sta. Bul. 84:1-178.
(page 148)

Welker, R. M. 1992. White apple leafhopper affects apple fruit quality and leaf gas

exchange. MS. Thesis. Virginia Polytechnic Institute and State University.
Blacksburg. 94p.

Whalon, M. E. and B. A. Croft. 1985. Dispersal of apple pests and natural enemies in
Michigan. Research Report. Michigan State University Agricultural Experiment
Station. p24.

Wise, J. C. 1990. Local dispersal of the potato leafhopper (Homoptera: Cicadellidae) in
response to alfalfa cuttings. MS. Thesis. Michigan State University. East
Lansing, Michigan.

CHAPTER 2

Potato leafhopper (Empoasca fabae Harris) (Cicadellidae: Homoptera) movement in
a diverse deciduous fruit agroecosystem

Abstract

The movement of the highly mobile potato leaﬂiopper (Empoasca fabae Harris)
was studied in Michigan orchard systems and the surrounding agroecosystem. We linked
potato leafhopper trap catch to potato leafhopper seasonal population ﬂuctuations and the
habitat structure in and adjacent to deciduous fruit orchards. We used an extensive
trapping network of geographically stable yellow sticky boards to monitor the potato
leafhopper in and around the habitats. The trap catch means followed a low — high — low
pattern as the season progressed. Signiﬁcant differences (p<0.05) were detected between
habitats in the mid-season sample dates. Spring seeded alfalfa was the habitat with the
largest means and greatest difference in 1996 (p<0.05). Alfalfa, soybeans, and apple
were the habitats with the highest trap catch means in 1997. Alfalfa, apple, cherry, and
soybeans had high populations of potato leaﬂiopper when temperatures and conditions
were favorable in the agroecosystem. Further research needs to be done to determine the
effects of managed habitat manipulation on potato leafhopper damage in sensitive

deciduous fruit crops.

17

Introduction

Empoasca fabae, the potato leafhopper, is highly polyphagous, feeding on over
200 plant hosts (Poos and Wheeler 1943, Lamp et. al., 1994). It is a pest in many
Michigan cropping systems, including alfalfa, potatoes, beans, and deciduous fruit trees.
It is also found in many non-crop habitats, including forest, old ﬁeld, and roadsides
(Lamp et. al. 1989). The potato leafhopper is very mobile, frequently migrating between
hosts within an agroecosystem and as a long-range migrant between southern
overwintering sites and northern summer habitat.

The potato leafhopper is unable to survive winter conditions in the Midwest
(Decker and Maddox 1987) and it disappears when temperatures fall below survival
thresholds. Decker and Cunningham (1968) report that potato leafhopper overwinter and
begin spring reproduction on weedy annual legumes in the states on the Gulf of Mexico.
Taylor and Shields (1995a,b) report the collection of potato leafhopper in Arkansas and
Tennessee in January, and the collection of potato leaﬂiopper from several Pinus spp. in
the overwintering range. The number of potato leafhopper available for migration north
in the spring depends on the availability and quality of host plants and the occurrence of
lethal temperatures encountered at the overwintering sites (Berberet and Hutchison
1994).

Potato leaﬂioppers move north on early-season air currents and arrive in Michigan
in mid-May to late June on spring weather systems. Potato leaﬂiopper arrival dates and
corresponding weather patterns have been tracked in the midwestem and eastern states

since 1951 (Maredia et. al. 1998). The exact weather transport conditions needed for

18

potato leafhopper migration to occur have been determined (Carlson et. al. 1991 , 1992).
It is possible to predict potato leafhopper migration and arrival from weather patterns in
the early spring. From 1986 until 1998, our lab has conducted a spring migration
detection trapping network. This extended and intense transect system conﬁrms the
potato leafhopper arrival date each year. From this transect data, we hypothesize that
potato leafhoppers begin feeding and reproducing on deciduous trees. They are the only
plants providing enough vegetative growth to support a phloem feeder when the potato
leaﬂiopper arrival occurs (DiCosty et. al. 1998, Kaeb and Whalon 1998).

The appearance of the first Michigan potato leafhopper generation depends on
spring transport events and degree day (base 50°F) heat accumulation following arrival.
The migratory generation is usually not large enough to cause economic damage to crops,
but potato leafhopper are prolific and the population may quickly rise to damaging levels
if optimum conditions occur. The potato leafhopper is multivoltine, with three to ﬁve
overlapping generations each year. A female can live up to six months and produce eggs
for much of her life span (DeLong 1938). There is no correlation between the arrival date
and the subsequent severity of potato leafhopper infestation (Maredia et. al. 1998).

Potato leafhoppers feed on the phloem tissue of host plants, puncturing, tearing
and distorting the cells in the vascular bundle as they use their proboscis to empty the cell
contents (Ecale and Backus 1995a). As the potato leafhopper probes into the plant tissue,
it secretes a salivary ﬂuid, which hardens into a sheath. This sheath remains in the plant
for a long period of time (Ecale and Backus 1995b). Potato leafhopper feeding behavior

and the resulting residue cause a V-shaped chlorotic area called ‘hopper burn.’ Hopper

burn reduces plant photosynthesis, stunts plant growth and reduces crop yields (DeLong
1971, Schoene 1932).

Michigan orchards are very ecologically complex (Whalon and Croft 1985). The
insect pest complex found in Michigan orchards can be signiﬁcantly inﬂuenced by
disturbance (Wise 1990), nutrient ﬂow (Stickler and Whalon 1985), ground cover
(Larson and Whalon 1987) and the surrounding habitats. Many studies have been done on
deciduous fruits and the damage caused by individual components of the pest complex.
None of the studies in the past 50 years mention potato leaﬂiopper as anything other than
an occasional occupant of orchards. The 1998 Michigan Fruit Spraying Calendar (Jones
et. al. 1998) states, as a side note, “most organophosphates (OPS) applied for other pests
will control potato leafhoppers.” The potato leafhopper has not been a pest in Michigan
orchards since OPs came into wide spread usage in the 19505. Prior to OPs, however, the
potato leafhopper was a serious orchard pest.

Rising environmental awareness and new pesticide laws, including the Food
Quality Protection Act of 1996, are threatening Michigan producers with the loss of OP
insecticides (Gray et. al. 1996, Peterson 1998). The “soft,” pest specific chemicals and
tactics being developed to replace the CPS for control of primary pests do not control
secondary non-target pests, especially one as mobile and polyphagous as the potato
leafhopper. The loss of chemical control exposes other weaknesses in the current
agricultural production systems. Commonly grown varieties of apple have little
resistance to a phloem damaging pest such as the potato leafhopper. The trees are also
grown on dwarf rootstocks, further lowering resistance. The stage is being set for the re-

emergence of an “old-fashioned” pest, the potato leafhopper.

20

 

We face a number of challenges as we transition the Michigan fruit production
system to softer, more environmentally friendly programs of pest control. Broad
spectrum pesticides allowed producers to virtually ignore the effects of surrounding
habitats on the pest complex within the orchard. With the loss of chemical control
options, the impact of the agroecosystem on potato leaﬂiopper/crop interactions becomes
more important.

We studied the movement of the highly mobile potato leaﬂiopper in Michigan
orchard systems and the surrounding agricultural landscapes to give us an idea of the
challenges that we will face as we begin the transition of Michigan fruit production
systems to a softer, more environmentally friendly program. This study attempts to link
potato leafhopper trap catch ‘population dynamics’ (Flinn et. al., 1986) during the
growing season to potato leaﬂiopper seasonal population ﬂuctuations and the habitat
structure in and adjacent to the deciduous orchards at Clarksville Horticultural
Experiment Station. The collected data was used to gain basic insight into the short-
range movement of potato leafhopper in the agroecosystem in the orchards and the

surrounding habitats.

Materials and Methods

Agroecosystem. We monitored the movement of potato leaﬂiopper in the diverse
agroecosystem at the Clarksville Horticultural Experiment Station during the 1996 and
1997 growing seasons. The station is managed for fruit crop research and ﬁeld crop

variety and spray trials. The composition of the crops in the agroecosystem changed with

21

normal agronomic crop rotations between the years. Vegetative maps of the station show
the habitats present during the respective years (Figures 2.1 and 2.2). In 1996, spring
planted alfalfa (alfalfal) was present. Soybeans, wheat, and several new apple plots were
added and several alfalfa ﬁelds were taken out in 1997.

Traps. Ninety-ﬁve geographically stable sticky board stations were used to
monitor the potato leafhopper in and around the habitats. The trap stations were
freestanding and consisted of a yellow sticky board hung from a movable crosspiece set
0.95m above the ground on a step-in electric fence post. The sticky boards were 6”x 8”
pieces of Ms” plywood painted safety yellow (Rust Stop, Ace Hardware Corp.) and
encased in one quart ziplock bags coated with Tanglefoot (Tangletrap, Grand Rapids,
MI).

Yellow sticky traps attract and capture potato leafhoppers. The yellow color
provides a visual stimulus, and when a potato leafhopper comes into contact with the
board, the sticky substance retains it. Sampling is continuous and information is
accumulated about the potato leafhopper population 24 hours a day across the period
between trap visits. The yellow sticky trap sampling method is dependent not only on the
insect density, but also on several other variables. Color attraction, light quantity/quality,
ﬂight behavior, wind speed, and temperature also affect the number of potato leafhopper
collected in a given sample (Wise 1990).

Sampling. We used an extensive trapping system, limiting the number of traps in
each habitat so many habitats could be sampled over a large geographic area. The station
was divided up into 19 - 20 acre blocks, and ﬁve trap stations were placed in each block.

Traps were placed in locations based on several operational considerations, including;

22

roads, insecticide treated plots, surface water, slope and aspect. Latitude and longitude
coordinates for each trap were recorded using a handheld Scoutmaster GPS unit (Trimble
Navigation, Sunnyvale, CA) and location maps were generated using ArcView GIS
(Environmental Systems Research Institute, Redlands, CA).

The composition of the vegetation surrounding each trap was recorded at the
beginning of each year and when changes were made. Potato leafhopper sampling events
were triggered by selected degree day (base 50°F) accumulation intervals during the
growing season (7 samples in 1996 and 21 samples in 1997). Potato leaﬂiopper
specimens on the trap at the time of sampling were recorded and removed using a metal
spatula on the sampling dates between sticky bag changes. The sampling objectives were
to detect potato leafhopper in a given habitat and to provide information on the status of
potato leafhopper in the habitat.

Analysis. Data was submitted to standard ANOVA, regression, mean separation,
and analysis of deviate tests. Statistical tests were preformed using Minitab (Minitab,
Inc., State College, PA). Log (x+1) transformed values were used in all statistical tests.
Tukey’s test, with the family error rate set at 0.05, was used for the ANOVA

comparisons. Non-transforrned values were presented in all ﬁgures and tables.

Results and Discussion

Data Transformation. Variances exceeded the means of the potato leaﬂiopper

trap catch numbers. From calculations based on Taylor’s power law (Southwood 1978,

Steel and Torrie 1980), the log (x+1) transformation, where x = potato leafhopper trap

23

catch, was utilized to stabilize variances. The regression lines generated by the
transformed (R2=0.9125) and non-transformed (R2=0.6691) means and variances are
shown in Figure 2.3.

Within Habitat. Most habitats show trap catch differences (p<0.05) over time.
The means :1: SEM, F-tests and p-values of the habitats for each sample date in 1996 and
1997 were reported in Table 2.1. In the habitats with trap catch differences, the means
followed a low — high — low pattern as the season progressed during each year. Alfalfa,
alfalfal, apple, cherry, grass, soybeans, and wheat followed the expected trends (Hogg
1985).

Trap catch in the corn was high early in the season, fell off abruptly at midseason
and remained low. In oak and woods habitat, potato leafhopper trap catch remained low
for most of the season. The trap catch means in six habitats were graphed at each sample
date during the two years (Figure 2.4). The scale of the y-axis in several of the graphs
varies, displaying the differentiation between years.

The trap efﬁciencies, in the habitats in which the potato leafhopper trap catches
differed from the expected mean trends, were likely effected by factors other than the
potato leafhopper densities. The traps placed in the corn measured the potato leafhopper
numbers early in the season. When the height of the corn exceeded the height of the traps
(1 m), the traps were obscured and few potato leafhoppers were collected on them. The
sticky traps were placed below the tree canopy in the mature wood and oak stands, and
did not measure potato leafhopper present in the tree canopy. We used the within habitat

analyses to determine the effectiveness of the traps in each habitat. The traps were

24

ineffective in woods, oak and corn after trap height was exceeded and the trap catch
numbers were dropped from further analysis.

Between Habitat. The potato leafhopper trap catch was low at the beginning and
ends of the growing seasons. No differences were detected between habitats in the early
and late sample dates in either year. The habitat mean :1: SEM, differences between the
habitats, F-test, p-value, and sum of trap catch for each sample date is reported for 1996
(Table 2.2) and 1997 (Table 2.3). Signiﬁcant differences (p<0.05) were detected between
habitats in the mid-season sample dates.

Spring seeded alfalfa (alfalfal) proved to be the habitat with the largest means
and greatest difference throughout the sample dates in 1996 (p<0.05). This alfalfa was
harvested late (after 1577 degree day [base 50° F]), and potato leafhopper populations
were allowed to grow for most of the season. The trend continued after the alfalfa was
cut, but the differences and means were less (p>0.05).

The high, early season trap catches in corn in 1997 may be explained by potato
leathpper early season emigration behavior. The low numbers collected from corn after
the height obscured the traps were dropped from the analysis in both years (Table 2.2 and
2.3) as discussed above.

The soybean habitat consisted of five soybean varieties from four different
companies (Asgrow, AG2701; Novartis [Northrup King], F20-B9; Pioneer, 9254 and
9294; Michigan Certiﬁed Seed, Conrad-94), and these varieties were used in herbicide
trials. Large patches of ragweed, lamb’s quarter and burdock were found near some of

the traps during part of the season. The high and ﬂuctuating potato leafhopper trap catch

25

in the soybean habitat (Figure 2.4b) may have been due to the combination of multiple
variety, weed presence, and herbicide spray schedule of this habitat.

Yearly habitat means :1: SEM were displayed for 1996 (Figure 2.5) and 1997
(Figure 2.6). These ﬁgures included data from several habitats with only one trap where
single sample period means could not be calculated. There were differences across the
habitats in 1996 (F=l7.52, p<0.0001) and 1997 (F=10.47, p<0.0001). Alfalfa] (1996)
and alfalfa, soybeans, and apple (1997) were the habitats with the highest trap catch

means, as predicted by the within year analyses.

Conclusions

More potato leaﬂioppers are caught in host habitats than in non-host habitats.
Alfalfa, apple, cherry, other deciduous fruit and soybean habitats have high populations
of potato leafhopper during the season when temperatures and conditions are favorable in
the agroecosystem. The trap efﬁciency impacts the number of potato leafhoppers caught
in some habitats, and trap efficiency can change during the season. Habitat management,
such as spraying or harvesting, can also impact the potato leaﬂiopper trap catch in the
broader agroecosytem.

Further research is necessary as we begin the transition of the Michigan fruit
production system to softer, more environmentally friendly programs of pest control.
Broader agroecosystem information about highly mobile, potentially destructive non-
target pests, such as potato leafhopper will become invaluable as the broad spectrum pest

control methods are lost. Future studies on potato leafhopper in the diverse fruit

26

agroecosystem should include more intensive studies of the habitat and between habitat
effects on crop damage. Further research is needed to determine the effects of managed
habitat manipulation on potato leafhopper damage to sensitive deciduous fruit crops
during the growing season and between seasons. Thresholds for economic damage in
fruit crops based on potato leafhopper populations in neighboring habitats should also be
determined.

Broad spectrum insecticides allowed fruit producers to virtually ignore the effects
of surrounding habitats on mobile, polyphagous pests within the orchard. Habitat studies
like this one and future ones are increasingly important, because producers will no longer

be able to depend on them to control non-target pest, such as potato leaﬂiopper.

27

 

A .

6000 ~
E
84000 y=158.3x-411.04
g R2 = 0.6691
g

 

 

 

 

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.- B ,
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u
2 25
1
0 r 1

 

 

0 0.5 1 1.5
log (mean + 1)

Figure 2.3. Taylor’s Power Law regression lines (A) non-transformed means
and variances showing that the data is not normally distributed (B) normally
distributed log (x+1) transformed means and variances.

28

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

g 60
3.601 A +1996
|_ 41—1997
40
2
g 20
I 04-1 .
0 1000 2000 3000
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3 20
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3 +1997
l" 10~
9 5-
S 04": , ,
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DengaHBmSOF)
g 20
a 15 C +1996
5 +1997
§ 10-
5° W
3 O—_I.—- , 1
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Dongay(Base50F)

Figure 2.4. Mean potato leafhopper trap catches in habitat categories by
degree day (base 50F) sample periods in 1996 and 1997, (A) alfalfa, (B) com,

(C) grass.

29

 

8

 

+19%

 

 

U

+1997

 

0|
J

Mean PLH Trap Catch
8

 

 

 

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': +1997
E 20- “W
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+1997

 

 

 

01

 

 

Mom PLH Trap Count
8

 

Figure 2.4 continued. Mean potato leafhopper trap catches in habitat
categories by degree day (base 50F) sample periods in 1996 and 1997 (D)
orchard, (E) soybeans, (F) woods.

30

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32

Mean PLH Trap Catches

 

20 — if

  

.5
O
l

  

 

 

   

o _ ,j . ~ ‘ :7 ' 7:. ‘ 1g
'\

,9 a" a” 9“ «9°96: 1991969990“ .6:
Figure 2.5. Means i SEM for all habitats, 1996. First year alfalfa

(alfalfal) is signiﬁcantly different (p<0.05; Tukey’s test) from all other
habitats.

 

15: 1997

Mean PLH Trap Catches
3

 

 

689 §§° $20 $60 (96‘ Qoé 4{”9ng $656 099 9°“ 0”} 059

Figure 2.6. Means d: SEM for all habitats, 1997. Soybeans, alfalfa and
apple are signiﬁcantly different (p<0.05; Tukey’s test) from all other
habitats.

33

References

Berberet R. C. and W. D. Hutchison. 1994. Sampling methods for insect management
in alfalfa, pp. 357-381. In L. P. Pedigo and G. D. Buntin [eds.]. Handbook of
sampling methods for arthropods in agriculture. CRC Press, Boca Raton, Florida.

Carlson, J. D., M. E. Whalon, D. A. Landis, & S. H. Gage. 1992. Springtime weather
patterns coincident with long distance migration of potato leafhopper into
Michigan. Agricultural and Forest Meteorology. Elsevier Science Publishers
B.V., Amsterdam. 59: 183-206.

Carlson, J. D., M. E. Whalon, D. A. Landis, & S. H. Gage. 1991. Evidence for long-
range transport of potato leafhopper into Michigan. Reprinted from the Preprint
Volume of the Tenth Conference on Biometerology and Aerobiology and the
Special Session on Hydrometeorology. September 10-13, 1991. Salt Lake City,
Utah. Published by the American Meteorological Society.

Decker, G. C. & H. B. Cunningham. 1968. Winter survival and overwintering area of
the potato leafhopper. J. Econ. Entomol. 61: 154-161.

Decker, George C. and J. V. Maddox. 1987. Cold-Hardiness of Empoasca fabae and
Some Related Species. J. Econ. But. 60: 1641-1645.

DeLong, D. M. 1938. Biological studies of the leafhopper Empoasca fabae as a bean
pest. USDA Technical Bulletin 618.

DeLong, D. M. 1971. The Bionomics of Leaf hoppers. Ann. Rev. Entomol. 16:179-210.

DiCosty, U. R., M. J. Kaeb and M. E. Whalon. 1998. Characterize and quantify the
long range dispersal of potato leafhopper: Michigan. In Spatial dynamics of
leafhopper pests and their management on alfalfa. Reports prepared for the NC-
193 technical committee. Columbus, OH. March 4-5.

Ecale, C. L., and E. A. Backus. 1995a. Mechanical and salivary aspects of potato
leafhopper probing in alfalfa stems. Entomol. Exp. Appl. 77: 121-132.

Ecale, C. L., and E. A. Backus. 1995b. Time course of anatomical changes to stem
vascular tissues of alfalfa, Medicago sativa, from probing injury by the potato
leafhopper, Empoascafabae. Can. J. Bot. 73: 288-298.

Flinn, P. W., R. A. J. Taylor, & A. A. Hower. 1986. Predictive model for the

population dynamics of potato leafhopper, Empoascafabae (Homoptera:
Cicadellidae), on alfalfa. Environ. Entomol. 15: 898-904.

34

Gray, J. I., J. Flore, M. Hausbeck, L. Olsen, M. Whalon, C. Harris, J. Johnson, K.
Renner, P. Vergot, and P. Bills. 1996. The assessment of pesticides at risk in the
future of Michigan food and feed plant agriculture: A process. Michigan Agric.
Exp. Stn. Special Report 86. E. Lansing, MI. 15pp.

Hogg, D. B., 1985. Potato leafhopper (Homoptera: Cicadellidae) immature
development, life tables and populations dynamics under ﬂuctuation temperatures
regimes. Environ. Entomol. 14: 349-355.

Jones, A. L., L. Gut, J. Wise and J. Hull. 1998. Fruit Spraying Calendar 1998: for
commercial fruit growers. Michigan State University. Ext. Bull. E-154.

Kaeb, M. J. and M. E. Whalon. 1998. Michigan: Potato leafhopper trap catch in a
diverse apple agroecosystem. In Spatial dynamics of leafhopper pests and their

management on alfalfa. Reports prepared for the NC-193 technical committee.
Columbus, OH. March 4-5.

Lamp, W. 0., M. J. Morris, & E. J. Armbrust. 1989. Empoasca (Homoptera:
Cicadellidae) abundance and species composition in habitats proximate to alfalfa.
Environ. Entomol. 18: 423-428.

Lamp, W. 0., G. R. Nielsen, & S. D. Danielson. 1994. Patterns among host plants of
potato leafhopper, Empoasca fabae (Homoptera: Cicadellidae). J. Kansas Ent.
Soc. 67(4): 354-368.

Larson K. J. and M. E. Whalon. 1987. Crepuscular movement of Paraphlepsius
irroratus (Say)(Homoptera: Cicadellidae) between the groundcover and cherry
trees. Environ. Entomol. l6(5):1103-1106.

Maredia, K.M., M. E. Whalon , S. H. Gage and M. J. Kaeb. 1998. Observations of
First Occurrence and Severity of potato leafhopper, Empoasca fabae (Harris),
(Homoptera: Cicadellidae) in the North Central and Eastern United States. Great
Lakes Entomol. In Press, Vol. 31, Number 1.

Peterson, D. 1998. Will food quality protection act ﬁnish off fruit farmers: Half to 90%
of OP-insecticides may be lost by 1999. Michigan Farmer. 302(3): 18.

Poos, F. W. and N. H. Wheeler. 1943. Studies on the host plants of the leafhoppers of
the genus Empoasca. USDA Tech. Bull. No. 850:1-51.

Schoene, W. J. 1932. Leafhoppers injurious to apple trees. Va. Agr. Exp. Sta. Bul.
28321-34.

Southwood, T. R. E. 1978. Ecological methods: with particular reference to the study
of insect populations. Halsted, New York.

35

Steele, R. G. and J. H. Torrie. 1980. Principles and procedures of statistics: a
biometrical approach. Second edition. McGraw-Hill, New York.

Strickler, K and M. E. Whalon. 1985. Microlepidoptera species composition in
Michigan apple orchards. Environ. Entomol. 14:486-495.

Taylor, P. S. & E. J. Shields. 1995. Phenology of Empoasca fabae (Harris)
(Homoptera: Cicadellidae) in its overwintering area and proposed seasonal
phenology. Environ. Entomol. 24: 1096-1108.

Taylor, P. S. & E. J. Shields. 1995. Development of migrant source populations of the
potato leafhopper (Homoptera: Cicadellidae). Environ. Entomol. 24: 1115-1121.

Whalon, M. E. and B. A. Croft. 1985. Dispersal of apple pests and natural enemies in
Michigan. Research Report. Michigan State University Agricultural Experiment
Station. p24.

Wise, J. C. 1990. Local dispersal of the potato leafhopper (Homoptera: Cicadellidae) in
response to alfalfa cuttings. MS. Thesis. Michigan State University. East
Lansing, Michigan.

36

CHAPTER 3
Impact of two alternative management systems on potato leafhopper

(Empoasca fabae Harris) (Cicadellidae: Homoptera) in Michigan Apple Orchards

Abstract

The effect of two alternative orchard treatment systems on the numbers of potato
leafhopper (Empoasca fabae Harris) present in Michigan apple orchards was studied.
Yellow sticky traps were used to monitor the movement of potato leafhopper in and
around the apple plots and treatments. There were signiﬁcantly higher trap counts in the
unsprayed checks than in any of the spray treatments (P<0.003). There were no
signiﬁcant trap catch differences between three apple varieties in either year. The alfalfa,
apple and orchard habitats had trap catch means higher than other habitats over both
years. High trap catches were recorded in surrounding habitats in the sample period
following alfalfa cutting. Potato leafhopper is seasonally present in Michigan orchards
and is found in high numbers compared to non-host habitats. More work is needed to
determine the actual effects of treatment, variety, and surrounding habitat on the

economic impact of potato leafhopper in Michigan orchards.

37

Introduction

Empoasca fabae, the potato leafhopper (potato leafhopper), is highly
polyphagous. It feeds on over 200 plant hosts (Poos and Wheeler 1943, Lamp et. al.,
1994) and is a pest in many Michigan cropping systems, including alfalfa, potatoes,
beans, and deciduous fruit trees. The potato leafhopper is mobile as an interhabitat
migrant between hosts in an agroecosystem and as a long-range migrant between
southern overwintering sites and northern summer habitats.

Potato leafhoppers feed on the phloem tissue of host plants, puncturing, tearing
and distorting the cells in the vascular bundle as they use their proboscis to empty the cell
contents (Ecale and Backus 1995a). As the potato leaﬂiopper probes into the plant tissue,
it secretes a salivary ﬂuid that hardens into a sheath. This sheath remains in the plant for
a long period of time (Ecale and Backus 1995b). Potato leafhopper feeding behavior and
the resulting residue causes a V-shaped chlorotic area called ‘hopper burn.’ Hopper burn
reduces plant photosynthesis, stunts plant growth and reduces crop yields (DeLong
1971). High numbers of potato leafhopper cause direct economic damage to forage crops
and indirect damage to deciduous crops such as apples.

Many studies have been done on the damage caused by individual components of
the pest complex in deciduous fruits. None of the studies in the past 50 years mention
potato leafhopper as anything other than an occasional occupant of orchards. The 1998
Michigan Fruit Spraying Calendar (Jones et. al. 1998) states, as a side note, “most
organophosphates (OPs) applied for other pests will control potato leafhoppers.” The

potato leathpper has not been a pest in Michigan orchards since OPs came into

38

widespread usage in the 1950’s. Prior to CPS, however, the potato leafhopper was a
serious orchard pest.

There are many cooperative extension reports from the early 1900’s that describe
the potato leafhopper as a pest in apple orchards (Garman 1908, Washbum 1903,
Schoene 1932). According to Schoene (1932), potato leafhopper is a serious economic
pest of young apple trees and cultivated orchards. Potato leafhopper damage to apples
includes brown leaf margins in moderate infestations, and stunting, reduced vigor,
delayed bearing or even tree death in high infestations. Schoene and Underhill (1937)
published an exhaustive study on the susceptibility of the (then) commonly grown apple
varieties, classifying them as being low, moderate or highly susceptible to potato
leafhopper. There were no further studies of potato leafhopper damage after OPs came
into common orchard use.

Rising environmental awareness and new pesticide laws, including the Food
Quality Protection Act of 1996, are threatening Michigan fruit producers with the loss of
OP insecticides (Gray et. al. 1996, Peterson 1998). The “soft,” pest speciﬁc chemicals
being developed to replace the OPs do not control secondary non-target pests. The loss
of broad spectrum chemical control exposes other weaknesses in the current production
system. Commonly grown varieties of apple have little resistance to a phloem damaging
pest such as the potato leafhopper. The trees are also grown on dwarf rootstocks, further
lowering resistance. The stage is being set for the re-emergence of “old-fashioned” pests
such as potato leafhopper.

This study seeks to determine the effect of several alternative orchard treatment

systems on the numbers of potato leafhopper present in the orchards. The treatment

39

systems we studied included multiple pest control strategies; a hedgerow barrier,
environmentally friendly chemicals with novel modes of action, pheromone disruption
for control of lepidoptera pests, “bait and kill” techniques, and conventional OP
treatments. The objectives of the study were to 1) determine if any control of potato
leafhopper occurred in our varied treatment regimes, 2) if there were any differences
between potato leafhopper incidence in 3 apple varieties, and 3) the effects of the

vegetation surrounding our test plots on potato leafhopper trap catches.

Materials and Methods

Plots. We studied the movement of potato leafhopper in and around eight - 1/2
acre dwarf apple plots at the Clarksville Horticultural Experiment Station during the 1996
and 1997 growing seasons. The physical design and layout of the plots was developed
for a multidisciplinary project entitled “Alternative Pest Management Systems in Apple”
by a multidisciplinary committee. This committee included entomologists, plant
pathologists, horticulturists and agricultural economists. There were four replicates of
the IPM (no-barrier) plots and four replicates of the low input (barrier) plots. Each plot
was separated from the others by at least 150 m. Four rows of three apple varieties,
‘Empire,’ ‘Ida Red,’ and ‘Liberty,’ on Mark V dwarf rootstocks were randomly placed
within the plots (Figure 3.1). Barrier plots were surrounded by a 7 m high hedgerow
barrier of hybrid poplar, gray alder, and white pine trees (Figure 3.2).

Treatments. Each plot was divided up into three treatment subplots. The no-

barrier plots included a negative control, a “soft” treatment (imidacloprid, tebufenozide)

4o

and a positive control using conventional OP and carbamate treatments (methomyl,
guthion) (Figure 3. 1 A). The treatments within the barrier plots included a pheromone
disruption treatment, a non-OP soft treatment to control lepidopterous pests (spinosad,
imidacloprid, tebufenozide) and a negative control (Figure 3.1B). In 1996, we sprayed
the barriers themselves with garlic formulation as to make them repellant-protectant. In
1997, the barriers were sprayed with esfenvalerate to make them toxic to insect pests.

Traps. Two separate sets of yellow sticky traps were used to monitor the
movement of potato leafhopper in and around the plots and treatments. These traps were
used in separate analyses and were not compared. The “interior traps” were Pherocon
AM (Trece Inc, Sandoz Ltd) yellow panels. These traps were placed in the tree 1.5 m
above the ground. We placed one trap in each treatment of each variety for a total of 48
traps in the plots and 6 check traps in unsprayed orchards at other sites on the station.

The second set of traps, the “exterior traps,” measured the movement of potato
leafhopper around the edges of the plots. The traps were constructed of 1A” plywood
painted safety yellow (Rust Stop, Ace Hardware Corp.) and encased in one quart ziplock
bags coated with Tanglefoot (TangleTrap Corp, Grand Rapids, MI). The trap stations
were freestanding and consisted of a yellow sticky board hung from a movable crosspiece
set 0.95 m above the ground on a step-in electric fence post. Four traps were placed at
-X, X, X2, and X3 intervals (X=1.27m) on 4 sides of the V2 acre apple plots (Fig. 3.3). We
monitored 16 exterior traps per plot, for a total of 128 traps.

Sampling. Sampling events were triggered by selected degree day (base 50°F)
intervals during the growing seasons. Traps were checked on 13 sample dates during

1996 and 21 sample dates during 1997. Traps were changed once per month, and insects

41

 

Ida Red Empire Liberty

 

 

 

 

 

 

 

 

 

A

O.)

S

O ......................

E

8

a...

d:

o

.54

8 / / / / I / // / //// //
II III II I
II III II I
a! 55' :5 -
Empire Ida Red Liberty

 

 

 

B

Figure 3. l. (A) Diagram of an IPM (no barrier) plot, showing the randomly
assigned treatments and variety layouts used in the project. (B) Diagram of a
low input (barrier) plot.

42

O . . adm—
_Q gap: 30— a 5 much 2&3 05 wSU—H—Ogm mmg BEND 05 MO “GOES—aw N m 1m
.w . . .

. . m n n .. m
w * . . .

 

43

‘ “.1 r

..'

 

 

 

 

 

\l
A

X - Trap Location

El ' Barrier

Figure 3.3. Layout diagram of the yellow sticky trap stations
surrounding the “Alternative Pest Management Systems in Apple” plots
(not to scale).

were scraped off using a metal spatula on the sample dates between trap changes. The
composition of the vegetation surrounding the apple plots was surveyed and was used in
analyzing the potato leaﬂiopper trap count data. The latitude/longitude location of each
trap was also recorded using a Global Positioning System (GPS) (Scoutmaster, Trimble
Navigation, Ltd., Sunnyvale, CA).

Analysis. Data was submitted to standard ANOVA, regression, mean separation,
and analysis of deviate tests. Statistical tests were preformed using the IMP (SAS
Institute 1995) statistical package. The student’s t test (Steel and Torrie 1980) with error
rate set at 0.05 was used for analysis of variance (ANOVA) (SAS Institute 1995) test on
the effects of the barrier, habitat, variety and treatment on potato leafhopper trap catch.

The trap catch mean t SEM was presented in the tables and figures.

Results and Discussion

Barrier Treatments. There were significantly higher potato leafhopper trap
count means in and around the barrier plots than in the no barrier plots (P<0.0001) in
1996. There were more potato leafhopper captured on the exterior traps physically in the
barrier than on traps outside the barrier. In 1997, the barrier plots had trap count means
lower than the no barrier plots over the entire season (P<0.0569). The trends in mean
trap catch at ﬁrst arrival, ﬁrst generation, season population peak and season end were
shown (Figure 3.4). Differences were seen at the season peak sample date (~1300 degree
day [base 50°F]) when the population was the highest. There was little change in the no

barrier mean trap catch in the two years, even though the overall number of potato

45

leafhopper captured in 1997 was half the number captured in 1996. The difference
between the two years occurred in the barrier plots. Adults and nymphs were collected in
net sweep samples of the barrier in both years.

Hybrid popular (Populus sp.) is a deciduous tree that can serve as a host for the
potato leafhopper (Lamp et. al. 1994). The gray alder (Alnus incana) and white pine
(Pinus strobus) trees in the barrier, potential feeding sites, did not have as much of an
effect as the poplar on potato leafhopper in the barrier plots. These trees did not grow
well and remained short in comparison to the poplar trees (poplar = 7 m, gray alder and
white pine < 1 m).

In 1996, we treated the barrier with garlic to make it repellant to potato
leafhopper. This was not effective for potato leafhopper control in the barrier plots. In
1997, the barriers were treated with esfenvalerate to make them toxic. The barrier
treatment difference was reﬂected by the potato leafhopper trap catch and may account
for the mean trap catch differences between the two seasons in the barrier plots, when the
no barrier mean trap catches remained the same.

Spray Treatments. There were significantly higher mean interior trap counts on
the unsprayed checks than on any of the spray treatments (P<0.003) within the plots in
1997. We showed this by graphing the mean interior trap counts for treatments in the
banier and no barrier plots on seven sample dates in 1997 (Figure 3.5). Check trap
catches mirrored the trap catches in the no barrier treatments for most of the season. The
barrier traps had lower catches than the checks until after 1500 degree day (base 50F)
heat units. There were no treatment differences (p<0.05) observed on the exterior traps in

either year.

46

We expected to see a trap catch difference only in the OP treatments, as there was
no anticipated potato leaﬂiopper control in any of the other treatments. Esfenvalerate and
imidacloprid show activity against potato leafhopper in high doses, but the application
rate and the timing of the sprays was not conducive to potato leaﬂiopper control in the
treatments. Irnidacloprid, a nicotine analog, also had activity against potato leafhopper
natural enemies. The small size of the treatment areas, immigrations from outside
habitats, and the visual attractiveness of the yellow traps may have masked any treatment
effects.

Variety Differences. There were no signiﬁcant overall differences between the
three apple varieties in either year, however, differences were shown on individual
sample dates. Mean :1: SEM interior trap catches from the ﬁrst arrival, ﬁrst generation,
peak activity, population crash and season end sample dates were used to illustrate this
(Figure 3.6). At peak potato leafhopper activity in 1996, ‘Liberty’ showed higher potato
leafhopper counts than ‘Ida Red’ and ‘Empire’ (P<0.0676). In 1997, ‘Liberty’ showed
slightly lower counts than the other two varieties in the same sample period (p<0.3204).

The small plot sizes and immigration from surrounding habitats may have masked
variety differences if they occurred in our plots. None of the varieties present in our plots
were discussed in “Resistance of certain varieties of apple trees to injury by the
leafhopper (Empoasca fabae)” (Schoene 1937). This study can be summarized by saying
potato leafhopper is not equally injurious to all varieties of apples, but the differences in
the degree of injury are less when potato leafhopper is very numerous. Susceptibility of
apple varieties to potato leafhopper varies inversely with foliage pubescence (Schoene

1937). Similar results have been found in soybeans (Johnson and Hollowell 1935) and

47

glandular hair alfalfa (Sulc et. al. 1997). The three varieties we studied had
approximately the same amount of leaf pubescence, which may also explain the lack of
differences between the varieties.

Habitat Diﬂ‘erences. The mean :1: SEM exterior trap catches for the potato
leafhopper ﬁrst arrival, first generation, population peak, season end and pooled data
from all sample dates was presented for 1996 (Table 3.1) and 1997 (Table 3.2). In 1996,
the overall potato leafhopper population was higher and the differences in habitats were
not as pronounced as in 1997. More differences were apparent in 1997, with the non-host
habitats and the plot barriers having signiﬁcantly lower trap catches on several sample
dates and in the pooled data.

First arrival potato leaﬂiopper detection occurred in the apple habitat in 1996. In
1997, the ﬁrst potato leafhopper catches occurred on barrier and corn traps. Alfalfa,
apple and orchard habitats usually had trap catch means higher than other habitats over
both years. High trap catches were recorded in the woods, grass and apple habitats
surrounding alfalfa in the sample period following alfalfa cutting.

The difference in the barrier trap catch means between 1996 and 1997 was due to
the repellent vs. toxic treatments of the barrier between the two years. The high numbers
in corn compared to the other habitats in ﬁrst generation 1997 may have been due to the
attractiveness and visibility of the yellow traps compared to the corn foliage. The lack of
suitable plants in other habitats at this time of year for the adults to feed on may have also
had an impact. Disturbance (alfalfa cutting) pushed adult potato leaﬂioppers from the

disturbed areas into surrounding habitats, boosting trap counts.

48

 

 

30 a
-—+——Barner96 A
25 ‘ ~~I~-NoBam‘er96

 

 

  

 

Mean PLH Trap Catch

 

 

 

0 500 1000 1500 2000 2500 3000
Degree Day (Base 60F)

 

 

-+— Senior 97

_- 4... No Banier97
20 d ,i\ B

 

 

Mean PLH Trap Catch

 

 

 

 

0 500 1000 1500 2000 2500 3000
Degree Day (Base 50F)

Figure 3.4. Effect of the barrier on the potato leafhopper mean a: SEM
trap catch over time in 1996 and 1997. (A) There were signiﬁcantly more
captured in the barrier than the no barrier plots in 1996 (P<0.0001). (B)
There were fewer potato leaﬂropper captured in the barrier than the no
barrier plots in 1997 (P<0.0569).

49

 

  
  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

g 4— Pheromone
‘2 60 ~ ——I—- Barnersoft A
a + control
B
I- _
z: 40
.1
n.
5
g 20 ~
0 " I T r I
0 500 1000 1500 2000 2500
Degree Day (Base 60F)
3.
a.
E
I'-
:c
.r
a.
c
I
i
0 r r r— r
O 500 1000 1500 2000 2500

Degree Day (Base 60F)

Figure 3.5. Effect of treatment on mean PLH trap catch over time in 1997.
The mean potato leafhopper trap catch in the check was signiﬁcantly different
(P<0.001) than any of the treatments in the (A) barrier and the (B) no barrier
plots.

50

 

  
   
 

 

men-Ida Red
\ _s_Empire
——A—- Liberty

 

 

 

Mean PLH Trap Catch
8

   

 

 

 

 

 

0 4 . v . .
0 500 1000 1500 2000 2500 3000
DegreeDay(Base 50F)
40
men-UaRed
3°“ B -1997 +EmP'm
—~a--Liberty

 

 

   

 

Mean PLH Trap Catch
N
O

 

 

 

0 500 1000 1500 2000 2500 3000
Degree Day (Base 50F)

Figure 3.6. Effect of variety on the mean PLH trap catch over time in (A)
1996 and (B) 1997. Overall, there were no signiﬁcant differences between
the different varieties (P<0.05). Liberty showed higher numbers at one
sample date in 1996, but showed lower numbers at the same degree day
(base 50F) in 1997.

51

Table 3.1. Potato Leafhopper (PLH), Empoasca fabae (Harris), trap count means
in a replicated IPM apple orchard system related to surrounding habitat, 1996.

 

 

 

Habitat] Arrival First Generation Alfalfa Cutting Season End All dates
DD..273 005.706 005.1333 005.2529 combined
x:sr32 x:sra2 x:SE2 x:sr=.2 x:sra2

Apple 0.05:0.3 “ 1.8:02 " 28.9:42 " 2.7:03 ' 9.8:06"

Alfalfa 00:00: 1.8:08 ' 17.8:4.8 ‘ 3.4:05 ‘ 8.7:20'

In Barrier 00:00“ 05:03 b 201:8.2“ 2.1:07 ‘ 7.3:1.6a

Woods 0.0:00a 00:0.0 “ 28.0:140a 1.5:05 “ 08:27 '

Orchard 00:0.0a 1.4:09a 23.3:12.1 ‘ 26:10" 6.2:] .3 ‘

Out Barrier 00:0.0 “ 07:04 ' 195:7.7 ‘ 07:04 “ 54:09 h

Grass 00:00 “ 05:0.2 " 17.6:42 ' 2.0:04 " 4.6:05 b

Corn 00:0.0a 12:05“ 40:06' 06:06‘ 15:02"

 

lOrchard habitat includes peach, pear, apple, and cherry.
2Means followed by the same letter are not different at the P<0.05 level using Student’s t
(SAS Institute, 1996).

52

Table 3.2. Potato Leafhopper (PLH), Empoasca fabae (Harris), trap count means
in a replicated IPM apple orchard system related to surrounding habitat, 1997.

 

 

 

Habitat' Arrival First Generation Alfalfa Cutting Season End All dates
DD50261 DD50767 1305,1293 005.2451 combined
x:SE2 x:sr~:2 x:sr~:2 x:sr=.2 x:sr=.2

Apple 00:00 ': 58:07 ‘* 19.4:30a 0.1:004a 4.9:03a

Alfalfa 00:00" 52:21“ 26.4: 17.3 “ 00:003 6.1 :1 .8 “

In Barrier 03:03 " 12:06h 20:09h 00:00" 1.1 :02 "

Woods 00:0.0 “ 20:10 “" 14.0:3.0a 0.0:00 “ 3.3: 1 .1 "

Orchard 00:00 a 77:49 “ 25.7: 1 1.4 " 00:0.0 " 00:13 "

Out Barrier 01:01 " 2.0:12h 3.4:08 " 0.1:01 “ 14:02"

Grass 00:0.0 “ 2.0:03 " 9.2: 1 .3 “ 01:0.07 " 49:02 "

Corn 02:02 " 14.2:2.1 ° 5.2: 1 .5 b 04:04 a 33:07 "

 

lOrchard habitat includes peach, pear, apple, and cherry.
2Means followed by the same letter are not different at the P<0.05 level using Student’s 1

(SAS Institute, 1996).

53

Conclusions

Potato leafhopper is seasonally present in Michigan orchards and is found there in
reasonably high numbers when compared to non—host habitats. More studies need to be
undertaken to determine the actual effects of spray treatment, variety, and surrounding
habitat on the economic impact of potato leaﬂiopper in Michigan orchards. We have
barely scratched the surface and were unable to find other research in the past 50 years
that combined both potato leaﬂlopper and apple.

This study has revealed several interesting questions regarding the use of a
hedgerow barrier strategy for management of potato leaﬂlopper in orchards. The poplar
trees were shorter in the ﬁrst season, and the gray alder and white pine remained small
for the entire project. This study ended up testing a poplar barrier, not the mix, for pest
control. Poplar is a deciduous tree, and is a potential potato leafhopper host. In the first
year, we found that the barrier was attractive to potato leafhopper. In the second year, we
exploited this by making the barrier toxic. Did the poplar trees attract potato leafhopper
more strongly than the apple trees? Were the potato leafhopper drawn from the apple by
the poplar and killed, or were they simply unable to reach the apple because of the poison
barrier blocking them? Further work needs to be done to determine whether this was an
“attract and kill” strategy or a poison barrier strategy.

Future studies are needed to determine the impact of secondary, non-target pests,
including the potato leafhopper and other mobile pests, on Michigan apple and deciduous
fruit orchards as we begin the transition of the Michigan fruit production system to softer,
more environmentally friendly programs of pest control. Larger plots, additional modern

varieties of apple, and more absolute sample methods should be included in future

54

studies. However, in an experiment of the suggested scale, the experimental design
constraints of time, money, equipment and amount of information gained must be
carefully balanced. The effect of managing the habitat surrounding orchards for potato
leafhopper control on economic damage to the crop needs to be studied, and thresholds
for economic damage in apple, based on potato leafhopper populations in neighboring
habitats should be determined.

Broad spectrum insecticides have ceased to be the answer to controlling
secondary pests because of FQPA, rising environmental awareness, and insect resistance.
Alternative pest control strategies, such as growing apple varieties resistant to potato
leafhopper damage (Schoene 1937) and using ground cover mixes of plants undesirable
to potato leaﬂropper (Larson and Whalon 1987, Roda et. al. 1997), must be developed to
ﬁll the pest control vacuum. Perhaps broad scale (i. e. barriers and trap crops) and within
orchard habitat manipulation can answer some of the perplexing pest control challenges

we face in this changing production system.

55

References

DeLong, D. M. 1971. The Bionomics of Leaf hoppers. Ann. Rev. Entomol. 16:179-210.

Ecale, C. L., and E. A. Backus. 1995a. Mechanical and salivary aspects of potato
leaﬂiopper probing in alfalfa stems. Entomol. Exp. Appl. 77: 121-132.

Ecale, C. L., and E. A. Backus. 1995b. Time course of anatomical changes to stem
vascular tissues of alfalfa, Medicago sativa, from probing injury by the potato
leafhopper, Empoasca fabae. Can. J. Bot. 73: 288-298.

Garman, H. 1908. Apple orchard pests in Kentucky. Ky. Agr. Exp. Sta. Bul. 133:1-71.
(page 57)

Gray, J. 1., J. Flore, M. Hausbeck, L. Olsen, M. Whalon, C. Harris, J. Johnson, K.
Renner, P. Vergot, and P. Bills. 1996. The assessment of pesticides at risk in the
future of Michigan food and feed plant agriculture: A process. Michigan Agric.
Exp. Stn. Special Report 86. E. Lansing, MI. 15pp.

Johnson, H. W. and E. A. Hollowell. 1935. Pubescent and glabrous characters of
soybeans as related to resistance to injury by the potato leafhopper. J our. Agr.
Res. 51:371-381.
Jones, A. L., L. Gut, J. Wise and J. Hull. 1998. Fruit Spraying Calendar 1998: for
commercial fruit growers. Michigan State University. Ext. Bull. E-154.

Lamp, W. O., G. R. Nielsen, & S. D. Danielson. 1994. Patterns among host plants of
potato leaﬂiopper, Empoasca fabae (Homoptera: Cicadellidae). J. Kansas Ent.
Soc. 67(4): 354-368.

Larson K. J. and M. E. Whalon. 1987. Crepuscular movement of Paraphlepsius
irroratus (Say)(Homoptera: Cicadellidae) between the groundcover and cherry
trees. Environ. Entomol. 16(5): 1 103-1 106.

Peterson, D. 1998. Will food quality protection act ﬁnish off fruit farmers: Half to 90%
of OP-insecticides may be lost by 1999. Michigan Farmer. 302(3): 18.

Poos, F. W. and N. H. Wheeler. 1943. Studies on the host plants of the leafhoppers of
the genus Empoasca. USDA Tech. Bull. No. 850: 1-51.

Roda, A. L., D. A. Landis, and M. L. Coggins. 1997. Forage grasses elicit emigration
of adult potato leaﬂiopper (Homoptera: Cicadellidae) from alfalfa-grass mixtures.

Environ. Entomol. 26(4):745-753.

SAS Institute, 1995. JMP user’s guide: statistics, version 3.1 ed. SAS Institute, Cary,
NC.

56

Schoene, W. J. 1932. Leafhoppers injurious to apple trees. Va. Agr. Exp. Sta. Bul.
283:1-34.

Schoene, W. J. and G. W. Underhill. 1937. Resistance of certain varieties of apple
trees to injury by the leaﬂlopper (Empoasca fabae). Va. Agr. Exp. Sta. Tech. Bul.
59:1-16.

Steele, R. G. and J. H. Torrie. 1980. Principles and procedures of statistics: a
biometrical approach. Second edition. McGraw-Hill, New York.

Sulc, R. M., J. S. McCormick, L. H. Rhodes, C. Penrose, and E. Volbom. 1997.
Ohio forage performance trials 1997. Ohio State University Extension, OARDC.
Series 195. December 1997.

Washbum, F. L. 1903. Injurious insects of 1903. Minn. Agr. Exp. Sta. Bul. 84:1-178.
(page 148)

57

CHAPTER 4

Mapping potato leaﬂiopper (Empoasca fabae Harris) (Cicidellidae: Homoptera)
movement in a diverse deciduous fruit agroecosystem using GIS

Abstract

The spatial distribution of potato leaﬂropper populations in the habitats of a
diverse deciduous fruit agroecosystem was characterized using Global Information
Systems (GIS). An extensive trapping system of geographically stable yellow sticky
boards was used to monitor the potato leaﬂlopper movement in and around the habitats.
The spatial distribution of the trap catch was computed and mapped using ArcView GIS
(Environmental Systems Research Institute, Redlands, CA). The highest average trap
catch intensities in the two years were found in habitats comprised of ﬁrst year alfalfa
followed by alfalfa and alfalfa followed by soybeans. Alfalfa had the strongest map
surface intensities overall, indicating that it had the highest potato leafhopper trap catch.
The orchard habitats had potato leafhopper populations visible on all map surfaces when
potato leaﬂiopper was present in the agroecosystem. Potato leafhopper population
intensities did appear to move over time based on the trap catch surface maps. The
spatial distribution of the potato leafhopper closely followed the spatial distribution of
host habitat. The high trap catch map surface area expanded and contracted in host

habitats as the potato leafhopper populations followed seasonal cycles.

58

Introduction

Geographic Information Systems (GIS) are powerful tools for mapping insect
populations over a geographic area (Gage et. al. 1990). The use of GIS to link data sets
related only by a geographic location makes it possible to map the spatial dynamics of a
pest population in a diverse agroecosystem. GIS map layers allow the effects of other
landscape elements, including temperature, vegetation, slope, and time, to be included in
pest population spatial models. State-wide gypsy moth studies have been conducted in
Michigan over the past ten years using GIS (Gage and Pijanowski 1993, Pijanowski and
Gage 1996).

Empoasca fabae, the potato leafhopper, is highly polyphagous. It feeds on over
200 plant hosts (Poos and Wheeler 1943, Lamp et. al., 1994) and is a pest in many
Michigan cropping systems, including alfalfa, potatoes, soybeans, and deciduous fruit
trees. It is also found in many non-crop habitats, including forest, old field, and roadsides
(Lamp et. al. 1989). The potato leafhopper is mobile as an interhabitat migrant between
hosts in an agroecosystem and as a long-range migrant between southern overwintering
sites and northern summer habitat.

The potato leafhopper is unable to survive the winter temperatures in the Midwest
(Decker and Maddox 1987) and it disappears each winter when the temperatures fall
below survival thresholds. Each spring, potato leafhoppers move north on early season
air currents and arrive in Michigan in mid-May to late June on spring weather systems.
Potato leaﬂlopper arrival dates and corresponding weather patterns have been tracked in

the midwestem and eastern states since 1951 (Maredia et. al. 1998). The exact weather

59

transport conditions needed for potato leafhopper migration to occur have been
determined (Carlson et. al. 1991, 1992). It is possible to predict potato leaﬂiopper
migration and arrival from weather patterns in the early spring.

From 1986 until 1998, our lab has conducted a potato leafhopper spring migration
detection trapping network. This extended, intense, GIS linked transect system conﬁrms
the potato leafhopper arrival date each year. From this transect data, we hypothesize that
potato leaﬂiopper begins feeding and reproducing on deciduous trees because these are
the only plants with sufﬁcient vegetative growth to support a phloem feeder at the time of
potato leaﬂlopper arrival (DiCosty et. al. 1998, Kaeb and Whalon 1998).

The migratory generation is usually not large enough to cause economic damage
to crops. However, under optimum conditions, potato leafhopper are proliﬁc and the
population may rapidly rise to damaging levels. The potato leafhopper is multivoltine,
with three to ﬁve overlapping generations each year. A female can live up to six months
and produce eggs for much of her life span (DeLong 1938). There is no correlation
between the arrival date of the migratory generation and the subsequent severity of potato
leaﬂlopper infestation (Maredia et. al. 1998).

Michigan orchard agroecosystems are very ecologically complex (Whalon and
Croft 1985). Disturbance (Wise 1990), nutrient ﬂow (Stickler and Whalon 1985), ground
cover (Larson and Whalon 1987) and the surrounding habitats can signiﬁcantly inﬂuence
the insect pest complex. Many studies have been done on deciduous fruit and the damage
caused by individual components of the pest complex. In the past 50 years, none of the
studies mention potato leaﬂiopper as anything other than an occasional occupant of

orchards. The 1998 Michigan Fruit Spraying Calendar (Jones et. al. 1998) states, as a

60

side note, “most organophosphates (OPs) applied for other pests will control potato
leafhoppers.” The potato leafhopper has not been a pest in Michigan orchards since OPs
came into wide spread usage in the 1950’s. Prior to GPS, however, the potato leafhopper
was a serious orchard pest.

Rising environmental awareness and new pesticide laws, including the Food
Quality Protection Act of 1996, are threatening Michigan producers with the loss of OP
insecticides (Gray et. al. 1996). The “soft,” pest speciﬁc chemicals and tactics being
developed to replace the CPS for control of primary pests do not control secondary non-
target pests, especially one as mobile and polyphagous as the potato leafhopper. The
stage is being set for the re-emergence of an “old-fashioned” pest (Schoene 1932), the
potato leafhopper.

We face a number of challenges as we transition the Michigan fruit production
system to softer, more environmentally friendly programs of pest control. Broad
spectrum pesticides allowed producers to virtually ignore the effects of the surrounding
habitats on the pest complex within the orchard. With the loss of chemical control
options, the impact of the agroecosystem on potato leafhopper/crop interactions becomes
vitally important.

The objectives of this study were to use GIS: to 1) characterize the spatial
distribution of potato leafhopper populations in a diverse agroecosystem. 2) Determine
which habitats had the highest potato leafhopper trap catch over time, 3) discover if the
population high density regions were moving over time, and 4) to find out which habitat

or portions of habitats were driving the population changes over time.

61

Materials and Methods

Agroecosystem. We monitored the movement of potato leaﬂiopper in the diverse
agroecosystem at the Clarksville Horticultural Experiment Station during the 1996 and
1997 growing seasons. The station is managed for fruit crop research and ﬁeld crop
variety and spray trials. The composition of the crops in the agroecosystem changed with
normal agronomic crop rotations between the years. Vegetative maps of the station show
the habitats present during the respective years (Figures 2.1 and 2.2). In 1996, spring
planted alfalfa (alfalfal) was present. Soybeans, wheat, and new apple plots were added
and several alfalfa ﬁelds were plowed under in 1997.

Traps. Ninety-five gee-static sticky board stations were used to monitor the
potato leafhopper in and around the habitats. The trap stations were freestanding and
consisted of a yellow sticky board hung from a movable crosspiece set 0.95 m above the
ground on a step-in electric fence post. The sticky boards were 6”x 8” pieces of Mr”
plywood painted safety yellow (Rust Stop, Ace Hardware Corp.) and encased in one
quart ziplock bags coated with Tanglefoot (Tangletrap, Grand Rapids, MI).

Yellow sticky traps attract and capture potato leafhoppers. The yellow color
provides a visual stimulus, and when a potato leafhopper comes into contact with the
board, the sticky substance retains it. Sampling is continuous and information is
accumulated about the potato leaﬂiopper population 24 hours a day across the period
between trap visits. The yellow sticky trap sampling method is dependent not only on the

insect density, but also on several other variables. Color attraction, light quantity/quality,

62

ﬂight behavior, wind speed, and temperature also affect the number of potato leafhopper
collected in a given sample (Wise 1990, Buntin 1994).

Sampling. We used an extensive trapping system, limiting the number of traps in
each habitat so many habitats could be sampled over a large geographic area. The station
was divided up into 19 - 20 acre blocks, and ﬁve trap stations were placed in each block.
Traps were placed in locations based on several operational considerations, including;
roads, insecticide treated plots, surface water, slope and aspect. Latitude and longitude
coordinates for each trap were recorded using a handheld Scoutmaster GPS unit (Trimble
Navigation, Sunnyvale, CA) and location maps were generated using ArcView GIS
(Environmental Systems Research Institute, Redlands, CA). The 100 m error in the GPS
unit induced by the U. S. Department of Defense greatly affected the map location of the
trap stations. The actual, physical positions of the traps varied considerably from the
computer generated locations (Figure 4.1).

The composition of the vegetation surrounding each trap was recorded at the
beginning of each year and during the seasons when changes were made. Potato
leafhopper sampling events were triggered by selected degree day (base 50°F)
accumulation intervals during the growing season (7 samples in 1996 and 21 samples in
1997). Potato leafhopper specimens on the trap at the time of sampling were recorded
and removed using a metal spatula on the sampling dates between sticky bag changes.
The sampling objectives were to detect potato leafhopper in a given habitat and to
provide information on the status of potato leafhopper in the habitat.

Analysis. All data was submitted to standard AN OVA, regression, mean

separation, and analysis of deviates tests. Statistical tests were preformed using Minitab

63

(Minitab, Inc., State College, PA). Log (x+1) transformed values were used in all
statistical tests. Tukey’s test, with the family error rate set at 0.05, was used for the
ANOVA comparisons.

Spatial analysis. The spatial distribution of the potato leaﬂiopper trap catch was
computed using ArcView and ArcView Spatial Analyst. Data from the ﬁeld was stored
and manipulated in the Microsoft Access (Microsoft Corp., Redmond, WA) environment.
For clarity, the data management stream is diagramed in Figure 4.2. Latitude and
longitude coordinates from the GPS were uploaded into Access and linked to the potato
leaﬂiopper trap catch, surrounding vegetation and habitat data. After the data was
formatted in Access, it was linked into ArcView tables.

Point maps of the X, Y coordinates and related data ﬁelds were mapped for each
sample date. From these points, the data was transferred into raster format. Surfaces of
the log (x+1), where x = trap catch, were calculated for each point map using the nearest
neighbor Inverse Distance Weighting Format (IDW) (ESRI 1996) to produce the raster
image.

Boolean maps of the high trap catch areas were generated for each degree day
(base 50F) sample surface. We considered low trap catch surface areas to have values
less <5.3 (<0.8 log(x+l) transformed) and high trap catch areas to have values >5.3,
based on the habitat means of alfalfa and apple in 1996 and 1997 and soybeans in 1997.
These habitats were signiﬁcantly different from all other habitats in 1997 (P<0.05).
Difference maps and intensity maps were generated from the boolean maps using the
map calculator. The difference maps were generated by subtracting the boolean surfaces.

The intensity maps were generated by adding the boolean images together, and the

 

Figure 4.1. Map of yellow sticky trap locations on the Clarksville
Horticulture Experiment Station. Each large rectangle on the maps
represents 10 acres. (A) Computer generated locations from GPS
coordinates, (B) Hand drawn locations from ﬁeld notes.

65

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66

 

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average intensity map was generated by adding the maps together and dividing by the
number of maps.

The resolution of the maps generated in ArcView was good, but due to the GPS
error, the precision of them was not. To compensate for this variance, a point vegetation
map for each year was generated. This vegetation map was overlaid on all surface maps
to be sure the habitat linked inferences were the result of potato leaﬂiopper trap catch in a

particular habitat, not due to the GPS variance.

Results and Discussion

Spatial Distribution. The highest trap catch intensities were visible on the east
side of the northwest quadrant and in the southeast extension of the station (Figure 4.3).
The eastern side of the station had very little trap catch activity. In 1996 (Figure 4.4A),
the highest intensities were found in the ﬁrst year alfalfa (alfalfal) on the right sides of
the northwest and southwest quadrants with a gradient between them. The northwest and
northeast comers of the station had little potato leafhopper activity. In 1997, the hot
spots were in the southeast extension and in the southwest corner of the station (Figure
4.4B), with several other spots in the middle of the station. The entire west side of the
station and the northeast quadrant had potato leafhopper activity of varying intensities.

The highest intensities on the two year average map were found in habitats
comprised of alfalfa] followed by alfalfa and alfalfa followed by soybeans. The habitat
on the eastern side of the station was comprised of corn, woods and grass during both

years. The maps showed very little activity, because corn and grass are not potato

67

leaﬂlopper hosts (Lamp et. al. 1994). Although the woods may have served as a host, the
traps were placed below the canopy of the mature trees (Table 2.1) and therefore, could
not measure the presence and intensity of potato leafhopper accurately.

The gradient that connected the alfalfal hot spots in 1996 contained several apple
orchards, and the other spots of medium intensity were in apple and cherry orchards. In
1997, many of the apple habitats showed high intensity. The activity in the northeastern
quadrant was driven by a trap that was in a weedy erosion strip in the corn, The high
intensity spot in the middle of the station was in weedy habitat, and the soybean habitat in
the southeastern extension also contained weeds.

Habitats. In 1996, potato leaﬂiopper was first detected in the apple habitat and
was mapped in the apple and cherry habitats early in the season (Figure 4.5A). These
habitats remained visible in most of the surfaces throughout 1996. Potato leafhopper
populations were mapped next in alfalfa and alfalfal habitats. These habitats had the
highest trap catch map surfaces for the entire season until the population dropped off at
the season end.

In 1997, potato leaﬂiopper was detected first in corn. Trap catch map surface
activity in the corn habitat remained higher than the expected level until the 1009 degree
day (base 50F) sample date (Figure 45B). No trap catch activity was mapped in corn
later in the season. Activity was mapped in the apple, cherry and other fruit habitats as
long as potato leaﬂiopper was present in the agroecosystem. Alfalfa showed high trap
catch activity on the degree day 1147, 1295 and 1435 maps. Some activity was mapped
in alfalfa earlier, but it was not as strong as in 1996. Soybeans had high activity mapped

at many sample dates throughout the season.

68

 

Trap catch
intensity

 

 

 

 

 

 

 

Veg96

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cheny
corn
grass
oak
peach
pear
weeds
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. -,Y¢g97

aKaHa
appb
cheny
corn
grapes
gmss
oak
peach
pear
soybeans
'weeds
“meat
woods

Figure 4.3. Surface of two year average trap catch intensity with (A) 1996
vegetation overlay and (B) 1997 vegetation overlay.

69

 

Trap catch
intensity

Ed?

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(DUI-#0010

 

 

 

 

 

 

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Veg97

aﬂaﬂa
apple
cherry
corn
grapes
grass
oak
peach
pear
soybeans
weeds
wheat
woods

Figure 4.4. Trap catch intensity surface maps of the Clarksville Horticultural
Experiment Station with vegetation overlays for (A) 1996 and (B) 1997.

70

 

 

583

 

 

706

 

Potato leafhopper trap catch surfaces

 

Log (x +1) Back
transformed transformed
0- 1.0
1.0-2.8
2.8-6.5

6.5- 14.7
14.7-28.8
28.8-55.3
55.3-1 10.2
1 10.2-215.7
215.7-422.7

 

 

 

Figure 4.5. (A) Nearest neighbor surface maps of transformed potato

leafhopper trap catches on individual degree day (base 50F) sample dates in
1996.

71

 

 

Figure 4.5. (cont’d). (B) 1997

72

Apple, cherry, peach, pear and alfalfa all serve as hosts for the potato leaﬂiopper
(Lamp et. al. 1994). Alfalfa had the strongest surface intensities overall, but at least some
of the fruit habitats were visible on all maps where potato leafhopper occurred. The
orchard habitat surfaces were visible from the background earlier and later in the seasons
than other habitats. This data supports our hypothesis that potato leaﬂropper begins
feeding and reproducing on deciduous trees because they are the only plants with enough
growth capable of supporting a phloem feeder at the time of potato leaﬂiopper arrival.
The late season potato leafhopper activity in deciduous fruit trees may be due to the
senescence and harvest of other hosts, while the trees still have leaves capable of
supporting potato leafhopper feeding.

The early season corn trap catch surfaces in 1997 may have been driven by potato
leafhopper early season emigration behavior and the attractiveness and visibility of the
yellow traps compared to the corn foliage. The lack of suitable plants in other habitats at
this time of year for the adults to feed on may have also had an impact. The traps became
ineffective after the corn height reached 1 m and obscured the traps (Table 2.1). If potato
leaﬂioppers remained in the corn habitat, the trap catches did not reﬂect it.

The soybean habitat consisted of ﬁve soybean varieties from four different
companies (Asgrow, AG2701; Novartis [Northrup King], F20-B9; Pioneer, 9254 and
9294; Michigan Certiﬁed Seed, Conrad-94), and these varieties were used in herbicide
trials. Patches of ragweed, lamb’s quarter and burdock were found near some of the traps
during part of the season. The dark surface area of the soybeans in many of the sample
date maps may have been due to the combination of multiple soybean variety and weed

presence in this habitat.

73

Population Movement. Potato leafhopper populations did appear to migrate
over time, based on the surface maps of trap catch. The areas of high trap catch surface
were isolated from seven matched degree day (base 50F) sample periods in 1996 and
1997 (Figure 4.6). Six difference maps (Figure 4.7) were generated from these maps to
illustrate the trap catch change between consecutive sample periods.

In early 1996, only small pockets of high potato leafhopper trap catch surface
were found. The first high population surfaces were found in the alfalfa habitats. In
midseason, some of the apple and cherry traps were showing high potato leafhopper
surface. High potato leafhopper surface area remained in alfalfa until the season end
sample. In 1997, the season was colder and the date was more advanced than the
equivalent degree day in 1996. The ﬁrst two maps showed potato leaﬂiopper high trap
catch surface in the corn, soybeans, alfalfa and some apple and cherry habitats. The traps
in the weeds (see above) were visible as high areas in ﬁve of the maps. In the low potato
leaﬂlopper population at the end of the season, the only habitats which still had small
pockets of high trap catch surface were apple and soybeans. The ﬁnal 1997 map showed
only apple.

The difference maps showed how the population changed over time. In the early
season sample periods, most of the changes were increases. The exception to this was the
corn in the northwestern corner of the station in 1997. At the end of the season, the
changes were decreases in most habitats as the populations fell. The difference maps
were difﬁcult to decipher, as there were residuals of the interpolation variances visible on
the maps. There were thin shells of “difference” which may not have been actual

differences visible on some maps.

74

1: Low trap catch area
High trap catch area

 

 

1632
2138 1961
2451
2529
B
A

Figure 4.6. Surface maps of high vs. low potato leaﬂiopper trap catch surface
for 7 selected sample periods in (A) 1996 and (B) 1997.

75

 

 

  

583-706

706-89 1

 

 

 

 

 

Trap catch change
ﬂ increase
:] no change
{3 decrease

 

 

 

 

 

 

 

 

    

2138-2529

A

Figure 4.7. Potato leafhopper high trap catch surface differences for 6 selected

sample periods in (A) 1996 and (B) 1997.

76

    

61 1-767

 
  

       
   
   

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210%" '3 .‘ 5.
767-1009

 

 

 

 
   

 

1632-1961

 

1961-2451 L——|

 

 

B

Conclusions

The spatial distribution of the potato leafhopper closely followed the habitat
vegetation present in the agroecosystem. When there were potato leafhopper present in
the agroecosystem, presence of host plants = presence of potato leafhopper. Potato
leaﬂiopper appeared in some non-host habitats during the study, but other factors,
including the presence of host plants and emigration behavior may have had an impact on
these populations. The alfalfa habitat had the highest populations over the two years.
Alfalfa and the deciduous fruit orchards had the most consistent populations, and the
soybean and weed habitats had high population intensities in 1997. Potato leafhopper
population hot spots moved over time as the populations followed their seasonal cycles.
The populations peaked in some habitats but remained steady in fruit.

There were some weaknesses in this study that need to be corrected in future
studies. The lack of accuracy in habitat intensity analysis due to the error in the GPS unit
can be corrected by using differential GPS (DGPS) technology. The relative yellow trap
sampling technique needs to be augmented with other, more absolute sampling
techniques. However, in an experiment of the suggested scale, the experimental design
constraints of time, money, equipment and amount of information gained must be
carefully balanced.

This project barely scratched the surface of GIS capabilities in agroecosystem and
pest studies. There are many other GIS tools that can be incorporated into future studies.
Overlay maps of vegetation, greening index and productivity can be produced by screen

digitization of time sequence satellite images. Soil maps, topographic maps and land use

77

maps can also be obtained or digitized for the study area. These overlays, combined with
powerful spatial statistics, can add new dimensions to the pest model. Predictions based
on the spatially improved agroecosystem/pest model can be tested in the ﬁeld using
DGPS linked GIS. When the model is deemed accurate in small trials, pest thresholds in
adjacent habitats can be determined and the model scaled up to commercial
agroecosystem size for use in conjunction with precision agriculture and integrated pest

management.

78

References

Buntin, G. D. 1994. Developing a primary sampling program, pp. 99-115. In L. P.
Pedigo and G. D. Buntin [eds.]. Handbook of sampling methods for arthropods in
agriculture. CRC Press, Boca Raton, Florida.

Carlson, J. D., M. E. Whalon, D. A. Landis, & S. H. Gage. 1992. Springtime
weather patterns coincident with long distance migration of potato leaﬂiopper into
Michigan. Agricultural and Forest Meteorology. Elsevier Science Publishers
B.V., Amsterdam. 59: 183-206.

Carlson, J. D., M. E. Whalon, D. A. Landis, & S. H. Gage. 1991. Evidence for long-
range transport of potato leaﬂiopper into Michigan. Reprinted from the Preprint
Volume of the Tenth Conference on Biometerology and Aerobiology and the
Special Session on Hydrometeorology. September 10-13, 1991. Salt Lake City,
Utah. Published by the American Meteorological Society.

Decker, George C. and J. V. Maddox. 1987. Cold-Hardiness of Empoasca fabae and
Some Related Species. J. Econ. Ent. 60: 1641-1645.

DeLong, D. M. 1938. Biological studies of the leafhopper Empoasca fabae as a bean
pest. USDA Technical Bulletin 618.

DiCosty, U. R., M. J. Kaeb and M. E. Whalon. 1998. Characterize and quantify the
long range dispersal of potato leafhopper: Michigan. In Spatial dynamics of
leaﬂlopper pests and their management on alfalfa. Reports prepared for the NC-
193 technical committee. Columbus, OH. March 4-5.

ESRI. 1996. GIS by ESRI: Using the ArcView spatial analyst. Redlands, CA. p147.

Gage, S. H., T. M. Wirth, and G. A. Simmons. 1990. Predicting regional gypsy moth
(Lymantriidae) population trends in an expanding population using pheromone
trap catch and spatial analysis. Environ. Entomol. 19: 371-377.

Gage, S. H. and B. Pijanowski. 1993. Application of remote sensing and analysis of
digital landscape maps to assess ecological risk from pest populations.
Proceedings, 25‘h International Symposium, Remote Sensing and Global
Environmental Change. pp. 390—402.

Gray, J. 1., J. Flore, M. Hausbeck, L. Olsen, M. Whalon, C. Harris, J. Johnson, K.
Renner, P. Vergot, and P. Bills. 1996. The assessment of pesticides at risk in the
future of Michigan food and feed plant agriculture: A process. Michigan Agric.
Exp. Stn. Special Report 86. E. Lansing, MI. 15pp.

79

Jones, A. L., L. Gut, J. Wise and J. Hull. 1998. Fruit Spraying Calendar 1998: for
commercial fruit growers. Michigan State University. Ext. Bull. E-154.

Kaeb, M. J. and M. E. Whalon. 1998. Michigan: Potato leafhopper trap catch in a
diverse apple agroecosystem. In Spatial dynamics of leafhopper pests and their

management on alfalfa. Reports prepared for the NC-193 technical committee.
Columbus, OH. March 4-5.

Lamp, W. O., G. R. Nielsen, & S. D. Danielson. 1994. Patterns among host plants of

potato leafhopper, Empoasca fabae (Homoptera: Cicadellidae). J. Kansas Ent.
Soc. 67(4): 354-368.

Lamp, W. O., M. J. Morris, & E. J. Armbrust. 1989. Empoasca (Homoptera:
Cicadellidae) abundance and species composition in habitats proximate to alfalfa.
Environ. Entomol. 18: 423-428.

Larson K. J. and M. E. Whalon. 1987. Crepuscular movement of Paraphlepsius
irroratus (Say)(Homoptera: Cicadellidae) between the groundcover and cherry
trees. Environ. Entomol. 16(5):] 103-1 106.

Maredia, K.M., M. E. Whalon , S. H. Gage and M. J. Kaeb. 1998. Observations of

First Occurrence and Severity of potato leaﬂlopper, Empoasca fabae (Harris),
(Homoptera: Cicadellidae) in the North Central and Eastern United States. Great
Lakes Entomol. In Press, Vol. 31, Number 1.

Pijanowski, B. and S. H. Gage. 1996. Case Study 1: GIS Fights the gypsy moth. In
Getting to know geographic information systems. Keith Clarke [ed].

Poos, F. W. and N. H. Wheeler. 1943. Studies on the host plants of the leafhoppers of
the genus Empoasca. USDA Tech. Bull. No. 850: 1-51.

Schoene, W. J. 1932. Leafhoppers injurious to apple trees. Va. Agr. Exp. Sta. Bul.
283:1-34.

Steele, R. G. and J. H. Torrie. 1980. Principles and procedures of statistics: a
biometrical approach. Second edition. McGraw-Hill, New York.

Strickler, K and M. E. Whalon. 1985. Microlepidoptera species composition in
Michigan apple orchards. Environ. Entomol. 14:486-495.

Whalon, M. E. and B. A. Croft. 1985. Dispersal of apple pests and natural enemies in

Michigan. Research Report. Michigan State University Agricultural Experiment
Station. p24.

80

Wise, J. C. 1990. Local dispersal of the potato leafhopper (Homoptera: Cicadellidae) in
response to alfalfa cuttings. MS. Thesis. Michigan State University. East
Lansing,.

81

APPENDIX A

APPENDIX 1

Record of Deposition of Voucher Specimens*

The specimens listed on the following sheet(s) have been deposited in
the named museum(s) as samples of those species or other taxa which were
used in this research. Voucher recognition labels bearing the Voucher
No. have been attached or included in fluid-preserved specimens.

Voucher No.: 1998‘1

Title of thesis or dissertation (or other research projects):

MOVEMENT AND RESPONSE OF POTATO LEAFHOPPER (EMPOASCA
FABAE HARRIS) (CICADELLIDAE: HOMOPTERA)TO HOST
PLANT HABITATS IN A DIVERSE APPLE AGROECOSYSTEM

Museum(s) where deposited and abbreviations for table on following sheets:
Entomology Museum, Michigan State University (MSU)

Other Museums:

Investigator's Name (8) (typed)
Melanie Joy Kaeb

 

 

 

Date 20 April 1998

*Reference: Yoshimoto, C. M. 1978. Voucher Specimens for Entomology in
Nerth America. Bull. Entomol. Soc. Amer. 24:141-42.

Deposit as follows:

Original: Include as Appendix 1 in ribbon copy of thesis or
dissertation.

Copies: Included as Appendix 1 in copies of thesis or dissertation.
Museum(s) files.
Research project files.

This form is available from and the Voucher No. is assigned by the Curator,
Michigan State University Entomology Museum.

82

APPENDIX 1.1
voucher Specimen Data

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No 2. 22 N2. N 2 22 22 222.222“ 2222222.? 222222.2- NN
N2 22 22 2.2 N N 2 22 2.32 NN2.NN.? $22.2- NN
NN N N 2 N 22 N N 25229 2.2.2.? 2.2.2. NN
N2. N N2 N N N N 2 2222o NN2.NN.? 252.2- NN
2.N N N N 22 N N 2 2222222 2222.22? $22.2- NN
222. N 2 2N 2 2 N N 2.2.-.22o NN2.NN.? 2222.2- 2.N
NN N: N 2.2 N N 22 22 2:220 22.22.? 22.N2.2- NN
2 2. N 22 N 2 N N 2:8 NNNNN? NN2.2- NN
22 N 2. 2 22 22 22 N .25220 NNNNN? $22.2- 2N
2222222 25.; NNNN NN2N NNN2 2222 2N2 2: am 252222222 02.2.2223 Neamaﬁ 22 22.2.2.

 

62:52:20 4.0 035,—.

88

APPENDIX C

 

N: N 22 22 2 2 N N E8 2222.? 22.2. 22222
N 22 22 22 2 v 2 22 88 N82? 22.2.2- 2:
N2 N N 22 2 2 N N E8 N22? NNNN2.2- 82
222 2. NN N2 22 N N N 222222222. 2232.? 2222.22- N222
NN N N 222 N N2 N 22 E8 NNN2.? 222.2- 2.222
222 N2 NN 2 N N 222 2 N222.222. NNN2.? N2.2.2- N222
N2 N2 22. NN 22 N 22 N 2222222222 N22? 22.2.2- N222
2N N 222 2.2 N 2 N 2 2.222.222. 22.? 9.2.2. 2222
N N 22 N 2 22 22 22 3.2222 22.2.? 222.2- 22222
N2 2 22 N 2. 2 22 22 .28 22.? 222.2- NN
NN N 22 22 2.N 22 22 22 228 N22? 2222. 2N
222. N 22 N2 2N N 2. 2 N222-22.. NNNNN? N2222- NN
22 22 N N 2. 22 22 22 22222.. NNNN? 222.2- 2N
NN 2. N 22 N2 2 2. N 883 282.? 222.2- NN
222 2. N NN N2 2 2 2 $222 NNNNN? 22.2- 2.N
NN N N 22 N 2 22 2 22222222.. NNNNN? N222- NN
NN N 2. 2.2 8 22 22 22 =8 222222.? 22.2- NN
2 22 N N 2 22 22 22 $822 2.2.? 222.2- 2N
N2 22 2. N N N 2 2 E8 NNNNN? 522.2. 8
N2. 2 22 2.2 NN N 2 N 22.83 NNNNN? 2222. N2
NN 2. N N 222 22 2 22 883 NNNNN? 2222.2- 2
N2 N 222 2. NN 2. N N 2.222222 22.2.? 222.2. 2
NN N2 NN ON 22 N 22 2 2222222 NN2.NN.N2. N222- 22
NN 2.N 2. 22 22 22 22 22 22222222222 222.? NNNNNNNN- 2
NN2 N 22 2 222.2 22 22 2 2222222222. 2222.? N22222- 2.N
2.N2 22 N2 NN 2.N 2. 22 22 22222222222 NNNNN? NN2.2- 2
N 22 N 22 22 22 22 22 V28 2.2.? 22222.2- N2
2 N 22 N 22 22 2 22 883 NNNNN? 282.2. 222
N 22 N N 22 22 22 22 2.22 NNN? 2222.2- 2222
NNN2 2228.2. NNNN NN2N NN2 2222 2N2 8N NNN 252222222 222.2.2223 N22322:: 22 22.2;

 

60:25:00 4.0 03.28

89

APPENDIX C

 

2.2 m o o o o o o N803 wngNe mmN~ mwa- 2 2
Nm 2: 2 a o 2 m o Noon? mmethe 393.3- m:
C m 2 o o 2 e N £2003 mmane $2 mN.nw- :—
m 2 m 2 o c o o xwo moZ-wNe mmE mN.mw- o:
Om On Q o o c o o mood? mNNN-wNe CNoeNﬁw- m:
N N o o o o o o 2283 m2 the mmweN.mm- e:
Nem @— mm M: ecN a 2 2 2822222222 Nwthe C ech.mw- m:
we o _N N 0 m2 : o 222-=33 Swane 233.3- N_ 2
No C 2 a 2m _N m N 22222—22222 SEQNe C wch.mw- : 2
ONe ON cm 02 New N— o o 22:22:22 wNwN-wNe 38.3. C:
Now 2 2 _N Ome : I c 22:22:22 wmwSNe 5008.3- 82
baa 322,—. aNmN ”2N hhmm owNm an 2:. mam 2533* 325325 o.o—Emu: % nah.

 

62:52:20 4.0 «Emu.

90

APPENDIX C

 

91

NN N N N N N N N V N2 2 V N V N N N 2.20 NNNNNV NNNNN.NN- NN
NN N N 2 N N 2 N N2 2 N 2 N N N 2 N NNNNN NVNNNNV 2NNN.NN. NV
VN N N N N N N N N N2 N N 2 2 N N N 2.20 NNNNNNV N2NNNN.N@ NV
N N N N N N N N N N N N N N 2 N N 88; NNNNNNV NNNNNNNN- NV
NN N N N N N N 2 2 N 2 2 N N N N N 88; NNNNNNV NNNNNNNQ NV
NV N N N 2 N N N 2 2 N N N N N2 N2 N 58 VNNNNV NVNNNNN. NV
VV N N N N N 2 N N N N 2 N N 2.2 N2 N 2:8 NNNNNNV NNVNNN.$ VV
NN N N 2 N N N 2 N N N N N V V N N 8% NNNNNNV NNNNNN.NN- NV
NV N N N N N N N N N N 2 N N2 N N2 2 58 NNNNNNV NNN2NN.NN- NV
VN 2 N N N N N N N N N N N N N N2 2 2:8 NVNNNNV N2NNNN.NN- 2V
NNN N N N 2 N N V NV NN2 NN NV NV N N N N NNNNN NVNNNNV NNNNNN.NN- NN
NN N N N N 2 N N N V2 N N N N 22 N N 293 NVVNNNV NNVNNNNN- NN
NN N 2 N 2 N N2 N N N2 22 N N N2 N2 N N 223 NNVNNNV NNNNNN. NN
NN N N N N N N N N N N N VN N2 N 2 2 58 NNNNNNV NNNNNNNN. NN
VN N N N N N N N 2 V2 N N NN N2 N N N 2:8 VNNNNV NNNNNN- VN
NNN N N 2 N2 N N 22 N2 NN NV NN N N2 N2 N N 2% NNVNNNV NNNNNNNN. NN
NN 2 N N 2 N N 2 N N2 V N N V N N N 22: NNNNNV N2NNNN.N¢ NN
NN N 2 N N N 2 N N N N N N V N N 2 N33 NNNNNV N2NNNN.NN- 2N
NN N N N N N 2 N N N N N N N N2 V N Na 2NNN.NV NNNNNN- NN
NN N N N N 2 V V N N N2 N N 2 N N N 295 NNNNNNV NNNNNNNN- NN
N: N N N 2 N N2 N N2 NN N2 N N N2 N2 N N 29: NNNNNNV NNNNNNNN- NN
N: N 2 N N N N N N NN N 22 N N NN 2 N 29: NN2NN.NV NNNN.NN- NN
NN N N N 2 N N N N N N N N N N 2 N 8% NN2NN.NV N2NNNN.NN- NN
3N9 2NVN NNNN NNNN NNNN 2N: NNN2 2.N: N82 NNV2 .NNN2 NV: 83 NNN 28 VNV NNN 25%: 02.32:: 2.33:3 N 9:9

 

 

252.3.— oEEaN mac «chug—N :28 you 2.2—5&3 5232582 3822 .2: nun—:52 5532.23.53 ugh.

 

.582 .5235 2082.6me 2382282253 0:39.56 222 3 5393809? 8332. 05 222 25qu 02953 22. .20 2x20 05 3 22022222838 23..—
EOm 0.88 NS ooEou .3 25532: 2528a 29:3 some N8 :88 9E 22$:va muauxuogomﬁmv 53022.23— o§om 280.2. .N.U 02.232.

APPENDIX C

 

NV N N N 2 N N N N N 2 V N N N N 2:8 NNNNNNV NNNNNN.NN.
VN N N N N N N N N N N N 2 N N2 2 2:8 NNNNNV NN2NN.NN.
NV N N N N N N 2 V N N N 22 N N N 2:8 NNNNNNV N2NN.NN.
NN N N N N 2 V N 2 N V N N N N N 8% NNNNNNV N2N2NN.NN.
NN N N N N N N N N 2 N N N N V 2 885 NNNNNV NNN2NNN¢
VN N N N N 2 N N N N 2 N N N N 2 3% NNNNN.NV N2NN.NN-
V2 N N N N N N N N N V N NV N VN N 2:8 NNNNNNV NNNNNNNN.
NN N N N N N 2 N N N N N 2 N N N N 2:8 NNNNNNV NVNVN.NN-
NN N N N N 2 N N N 2 N N N V V N N 2:8 NNNNNNV NVNVNNN.
N2 2 2 N N N N N N NN N N N2 22 N N V 88; NNNNNNV NVNNN.Nv
NN N N 2 N N N N N N N NN N V V V N 2N3 NNNNNNV NNNNNNNQ
N_ N N N N 2 N 2 N N N N N N N N N 38: NNNNNNV NNNN.NN.
V_ N N N N 2 N N N 2 N N N 2 2 V N 88,2 NNNNN.NV NNNNNQ
NV N N 2 N N V N N N 2 2 N N N2 N N 58 NNNNNV N2NNNN.NN.
NN N N 2 N N N N N N 2 N V N N N N :2... N2NNN.NV N2NNNN.NN.
NN N N N N N N N N V V N N N N N N 2% NNNNN.NV NNNNNNNN-
NN N N N 2 2 N N N N2 N 2 2 N N 2 N :20 NNNNNV N2NNNN.NN.
22 2 N N 2 N N 2 N N N N N N N N N NEN NNNNNNV NNNNNNNQ
N_ N N N 2 N N 2 N N N V N N N 2 2 :83 NNNNNNV NNVNN.NN.
NN N N N N 2 N N N 2 N N N N N N N 2:8 NNNNNNV NNNNNNN-
NN N N N N N 2 N N 22 N N2 N N N N N NNNN; NNNNNNV NNNNNN.NN.
NN N N N N 2 V N N N N N 2 N 2 2 N 8% NNVNN.NV NNNNNNNN.
N N N N N N N N N N N N N N N N N N255 NVVNNNV NVNNN.NN.
NV N N N N N N N N N N N N N N N 2 ENE NNVNN.NV NNNNNN.NN-
G N N 2 N 2 2 N N N N V N N 22 N 2 ENE NNVNN.NV NNNNNN.N@
NN N N N N N N N 2 N N N N 2 N N N :20 NNVNN.NV NNVNNN.N@
NV N N N 2 V N N N N V N V N N 2 N :56 N2VNN.NV N2VNNN.NN-
2N N N N N N 2 N 22 N N N V N N N N 2:8 NNNNNNV NNNNNN-
NN N N N N N N N N2 2 V N N N N N 2 N256 NNNNNNV NNNNNNNQ
25.; 2NVN NNNN NNNN NNNN 2X2 NNN2 NN: N82 NNV2 NNN2 NV: NN2: NNN 26 VNV NNN .523. 92.32:: 92.3% :3 N NE.

mm
an
R
on
mu
i
an
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K
on

mo
8
no
8
mm
3
no
No

2m
8
mm
mm
mm
mm
mm
3
mm
Nm
5

 

62.5230 NO 0359

92

APPENDIX C

 

E N N N N N N2 N N2 N2 N NN V2 N 22 N 2 8888 NN2NN.NV NNNNNN- NN2
NN2 N N N N N N2 N NN N2 N NN NN N2 N2 N2 N 58 NNNNNNV NVNN.N5 NN2
NNN N N N N N N N NV N NN N2 22 NN NN N2 N 88528 NNNNNNV NNNNNNNN- NN2
N: N N 2 2 2 V N N N V2 22 N2 NN 22 V2 N 8% NVNNN.NV NNNVNNNN. NN2
NN N N 2 N N N N N 2 N N N NN N2 N N 58 NNNNNNV N2NNNN.NNr VN2
N: N N N N N V N N 22 N N N NN NV N N 58 NNNNNNV NVNN.NN] NN2
VNN N N N N N N N NN NN NN 2N 2N NN N2 N2 N 88528 NNNNNNV 2VNN.NN. NN2
NN2 N N N N N N N V2 N V NN N N N 2 N 285, NNNNNV NVNN.NN- 2N2
VN N N 2 N N N 2 2 N N N N N N N N NNSN NNVNN.NV NNNNNNNN- NN2
NV N N N N N N 2 N N2 22 N N 2 N N N 88; NNNNNV NNNNNNNN- NN
NN N N N N N N N N NN N2 N2 N N N N N 88; NNNNN.NV N2N2NN.NN- NN
NV N N N N N N N N N N 2 V N NN N N 58 NNNNNNV N22NN.NN. NN
NN N N N N N N 2 N N N N N N N N N 8% NNNNNV NN2NN.NN. NN
NN N N N N N 2 N N N N N N V VN N N 88; NNNNNNV NN2NN.N9 NN
N2 N N N N N N N 2 2 N N N N 2 N 2 NNSN NNNNNNV NNNNNN. VN
8 N N N N N N N N N N N N N2 N2 N N 58 NNNNNNV NNNNN.NN- NN
NN N N N N N N N V N2 N N N N 2 N N 58 NNNNNNV NNNN.NN. NN
NN N N N N N N 2 N2 N V N N N 2 N N 8% NVNN.NV NNNNNNNNr 2N
NN N N N N 2 N N N N N N2 22 N2 N2 2 N 58 NNNNNNV NNNNNN.N@ NN
NN N N 2 N N V N N 2 N 2 NN N N N N 88; NNNNNNV NNNNNNNNN NN
2 N N N N N N N N N N N N 2 N N 2 88; NNNNNNV NN2NNN.NN- NN
NN 2 N N 2 2 N N N N2 N N2 N V N 2 2 82% NNVNN.NV NNNNNNN. NN
N2N 2 N N N N 2N NN VV NN N N2 N N2 N N2 N N_NNN NNVNN.NV NVNN.NN- NN
8. N N 2 2 2 N N N NN NV N N N V N N N85,, NVNNN.NV NNNNNNNN- NN
NN N N N 2 2 2 N N N2 2 N N N N N N 282.; NN2NN.NV NNNNNNNN- VN
_N N N N 2 2 N N N 2N N N V 2 N N N 2852, NNNNNNV NNNNNN- NN
N2 N N N N N N N N N N N 2 N 2 N N v.8 NVNN.NV NNNNNN- NN
V2 N N N N N N N N 2 N N N 2 N N2 N 88; NNNNNNV N2NNNN.NN- 2N
N N N N N N N N N N2 N N N N 2 2 N NNNNN NNNNV N2NNNN.Nw NN
25:5 2NVN NNNN NNNN NNNN 8N2 NNN2 NN: N82 NNV2 NNN2 NV: 82 NNN 23 VNV NNN 252.5 852.3 Noemi: N .229

 

62:52:20 .N.U m.32;

93

APPENDIX C

 

2 o o o o o o o o o o o o o o 2 o N228; mNmeNv NNNENdm- N22
Nw o o o o N o m ON N2 N2 22 o w m o o N228; 3:.va mmomﬂmm. N22
N o o o o o m o o o N o N m N N 2 3322 NVNNN.NN. 8023.8. 522
22 o N o o o 2 o o o o o 2 2 o 2 2 xmo NN2NN.NV 833.3- @22
n o o o o o o o m o 2 o o o o o o mace; mNNENv N2vaN.mm- m 22
E o o o o o o o 2 o o o m o m N o 833 323.3. mmmvam. v22
wnN o 2 o o 2 2. v o NN. mm mm o w o v N SE23 NwaNv DvmoNdw- N22
5N2 o o o N m N 2 2. N2. 02 22V o m m m o «233 nomanv ammooNdm- N22
VN2 o o o o o o o o NN N N m m m2 N 0 SEE noRva CmmmNdm. 222
N2 0 o o o o v N n mm m 2 20 m o 3 2V o 33% mNmBNv 58.3. 2222
22 o o o m o o c m m 2 8 25 m N N N o N253 wmmnva 5238.8. 82
256.2. 33 man cNNN emaN 2:2 emw2 emﬁ N82 mm: was 5.22 252 SN. 22w vmv 5mm .5332 0225234 92.3%0‘2 2222.2.

 

82.2.2250 .8 82.35

94

APPENDIX C

 

95

 

 

NN N V 2 N NN 22 V2 N 2 N N N N 228 _ m N
NV 2 N N N V N2 N N N N N N N 85.2.. Nx z N
NN 2 N N N N N N N N N N N N 858 5 Nx z N
NN V N 2 N N2 N2 N N 2 2 N N N 2&8 x z N
NN 2 N N2 N N2 N 2 N2 N 2 V N N 285 _ z N
NN N N N N N V 2 V 2 N N N N NNEN Nx m N
NN N N N N 2 N N2 N N N 2 N N 358 so Nx m N
NN N N2 N2 N N 2 N N 2 V N N N 298 x m N
E N N 2 N N2 N2 N 22 2 N V V N 298 _ m N
NN 2 N2 NN N N N N N N 2 N N N 288 Nx >22 2
V2 N N N N N N 2 N 2 N 2 2 N NNEN Nx 22 2
NN N V 2 N2 2 N 2 N 2 2 22 N N 298 x22 2
NN 2 N N N2 22 N2 N N N 2 N N N 222% . 22 2
NN N V N2 N N N 2 N N N N N N «.35 Nx m 2
NN N N N V N V N 2 2 N N N N NNSN Nx m 2
NN 2 2 N N N N N 2 2 N N 2 N 2.3 x m 2
NN N N N N N N2 V N N N V 2 N 2N3 _ w 2
N2 V N N N V 2 V N 2 N N N N 88. Nx z 2
NN N N V N V V N N N N N 2 N NNEN Nx z 2
N2 2 N N N V V N N N N o N N 288 x z 2
8 N N VN V N N V N N N N N N 225 _ z 2
NV V N N N NN N 2 N N N N N N .83 Nx m 2
N2 N N 2 N N N V N N N N 2 N 82% Nx m 2
NN N N N N N N N N 2 N N N N 2&8 x m 2
NV 2 N V2 N 22 N N N V N N N N 288 _ m 2
.592 NNNN NN2N NN: NNN2 NNN2 NNN2 NN: N282 2NN NNN NNN NNN NNN 282.222: .285 82.2
232.22— 0292.3 .32. 3.292. 2.08 .28 23.2393 guano—2.232 35cm 2: 3.29:. Z 2322322225222 222.2.

 

.032 .8222 ..o2N2m< 222 85.95 NSEowNENE 28.2 03322822.. Ems 2: 222 2528902983, 2: .20 22220 05 8 252222588 2822
ﬂow 035 .322 32mg 3 2882232: totem 2958 some 202 2.288 nab 282.85 muaax auNacNNEmv 892202282 3322 230.2. .MU 935.2.

Table (3.3. Continued.

 

Total

2529

1036 1176 1280 1333 1577 1722 2138

273 390 583 706 891

Habitat

Plot Trap

 

32
42

0

apple
in barrier

SX

SX2
SX3
2 WI
2 WX
2 WX2
2 WX3

2
2

74
98
80
36
28
37
27

18
25

17 12
21

13

O
0
0

apple
apple
apple

out barrier

10

18

14
14

13
12

21

grass

11

apple
apple

El

3

O

EX
EX2
EX3
NI

16
21

com

com
apple
apple
grass

corn

APPENDIX C

73
34
43
1 3

14

12

O
0

11

NX

NX2
NX3
SI

3
3

96

74

22

0

apple
apple
grass

FNNOv-r-l’xlx
IDCDNIOCDVQCD

F
OCMFOOOO

13
18
8
12
6
9
13
7

mFFCONFCDlN
Fv-v- PLO
v-wv-ocnmv-co

0
O
O
0
O
O
O
0

apple
apple
apple
apple
apple
out barrier

apple

grass

SX2
SX3
3 WI
3 WX
3 WX2

3 WX3
El

4

SX

3
3
3

95
78
35

17
20

26
23

14

O

EX
EX2

EX3

10

4

grass

82
59
33

41

14
1O
3

O
O
0

apple
apple

in barrier

NI
NX
NX2
NX3

4
4
4

209

12

87

85

0

alfalfa1

4

APPENDIX C

 

NN N 2 N N N N N N N N N N N NNQN Nx z N
NV N N N V N2 N N N 2 N N 2 N 293 x z N
NN2 N N NN NN NN N N N 2 V N N N 2N8 _ z N
NN N N N2 22 2N N N N 2 N 2 N N £323 Nx N N
NN N N NN N N2 N 2 N N N 2 N N N233 Nx N N
NN V N 2N V2 NN N N 2 N 2 N N N can; x N N
VN 2 N2 N2 N N N 2 2 N N N 2 N 226 _ N N
NN V N N N NV N2 N N N 2 N N N N228; Nx 22 N
2N2 N N N2 N NN NN N N N N N N N .228 :5 Nx 22 N
2NV 2 V NV NN NN2 VNN V N N N N N N 20.8 x 3 N
NNV N N NN NN NN2 NN2 NN N N N N 2 N 22.8 _ 22 N
N22 2 N N2 N NV NN N N N 2 N N N N28; Nx N N
VNN N N N2 N2 NN NN2 N N N N N N N 552 2: Nx N N
NN2 2 N N2 N NN NV 22 N2 N V N N N Nana x N N
NNN N N 2N NV N2 2 NN 2 2 N2 V V 2 N N 22.8 _ N N
NN N N V2 N V2 N2 N N N N N N N N85 Nx z N
N22 N 2 N NN NN VV N2 N N N N N N 523 N_ Nx z N
NN N N V2 V NN 2N N V N N N N N 2.2% x z N
NNN N 2 V2 NN NN2 NV NN 22 N N 2 N N 22.8 _ z N
2N N V N N N N N N N 2 2 N N 58 Nx N N
NN N N N N V2 2N N V N N V N N 5E2 :5 Nx N N
NV2 N N NN N2 NN NN V2 N2 N N N 2 N 22.92. x N N
NNN V N NN N2 NN NN N2 2N N N V 2 N 2qu _ N N
N2 N N N N N N N N N N N N N 58 Nx 2, V
NV N N V N N2 N2 N N 2 N N N N 5:52. :5 Nx 22 V
NN2 N N N N2 N2 NN N2 NN N N N N N 2822 x 2, V
2 2N N 2 2 N NN NN 2N N2 NN V N V N N N392. _ 22 V
NN N 2N N N N2 N2 N N N N N N N 23.2. Nx N V
NN N N N N V2 2N N 2 N 2 N N N 52:2 2 Nx N V
NN N N N 22 N2 V2 N N N N N N N 9N8 x N V
VN N V N N V2 N2 V N N 2 N N 2 2N8 _ N V
.53 NNNN NN2N NN: NNN2 NNN2 NNN2 E: 82 5 NNN NNN NNN NNN 33.2: N39 3:

 

60:25:00 .00 03:.

97

 

APPENDIX C

 

NN2 N V N2 N2 NN N2 NN N 2 2 N N N 2N8 x z N
NNN V 22 N2 NN NN VN NV N N N N N N 225 _ z N
N22 N N NV N2 N2 2N 22 N N V 2 N N N2_N2_N Nx N N
NN2 N N2 N2 VN NN N N2 N N N N N N 558 :5 Nx N N
NN2 N N 2N 2N N2 V2 NN N2 N2 N 2 N N 22.92. x N N
2VN N 22 NN N2 NN NN NN N N N N N N 29: _ N N
NN 2 N N N V2 V V N 2 N N N N 2.8 Nx 22 N
VN N N N N N2 NN N N 2 N N N N NNeN Nx 3 N
NN2 N2 N2 N2 N2 N2 NN NN N N N V N N 2qu x 3 N
NN2 N 22 N2 VN 2N N2 NN N2 N V 2 2 N 2&5 _ 22 N
NN2 N V N NN NN NN N2 N V N 2 N N 985 Nx N N
NN N V N V2 NN V2 N2 N2 N N 2 N N NNSN Nx N N
NN2 N N2 N N2 VN 22 V2 N N N N N N 29% xN N
2N2 22 N N2 V N N2 N N 2 N N 2 N 2&3 _ N N
NN2 N N N N NN VN NN 22 N N N N N NNSN Nx z N
NN N N N2 N N2 N V2 V 2 N 2 2 N NNNNN Nx z N
NN2 V N N N NV N2 N2 N 2 N N N N 296 x z N
2NN 2 N NN NN NV N2 NN V2 V N N N N 2qu _ z N
NV2 V N N2 N NN N2 N 2 2 V N N N 88; Nx N N
VN N N N V2 VN V N2 N2 N N N N N N233 Nx N N
N2N 2 N NN NN 2N N VN N N N 2 2 N 2N8 x N N
NN2 N N NN VN NN N N2 N2 V 2 N N N 296 _ N N
N2 N N 2 N N 2 N V N N N N N 3% Nx 22 N
NN N N N2 N N2 N2 V 2 N 2 N N N NNSN Nx 3 N
NN 2 VN V N2 N N 2 N N N N N N NaNN x 22 N
NN2 N NN N2 NN NN N2 N2 NN V 2 N 2 N 2N8 _ 2, N
NN2 N V N V2 NN NN V N N N N N N 58 Nx N N
NN N N N N N N N N N N N N N 3% Nx N N
NN N N2 NN N N2 N2 N N N N N 2 N 2N8 x N N
NN2 N N2 NN NN NN N N N 2 N V 2 N 03% _ N N
NN2 V N V2 NN NV N2 22 V 2 2 2 N N 935 Nx z N
.802 NNNN N: N: NNN2 NNN2 NNN2 NN: NNN2 2NN NNN NNN NNN NNN 232%: may a:

 

60:55:90 .90 03.2.“.

98

APPENDIX C

 

 

NV2 N N 22 22 NV VN NN 2 N N N N N 2.8 Nx 22 N
NN N V N N 22 N N N 2 2 N N N 5E2 =5 Nx 2, N
N2N N N2 N2 N2 N2 NN N N N 2 N N N 29:. x 22 N
2NN N N2 N2 NN 2N NN NN N N N N V N Naam _ 3 N
NN N N N2 N V2 V V2 N N N N N N NNSN Nx N N
NN2 N N N NN N2 NN NN V N N N N N 5E8 5 Nx N N
NN2 N N NV N2 N2 NN VV V N N 2 N N 285 x N N
N2N N N NV VN NV NN NN N N2 N V N N 22.8 _ N N
NN N N N N N N N2 2 N 2 N N N NNSN Nx z N
N N N 2 N2 NN N2 22 N N N N N N 5:52. s Nx z N
.58. NNNN NN2N NN2 NNN2 NNN2 NNN2 NN: NNN2 2NN NNN NNN NNN NNN 32%: Nae 22.2

 

60:52.30 6.0 952$.

99

APPENDIX C

 

 

NN2 N N N N N N 2 N2 2N N2 N N2 N N2 N N N 2.23% _ N N
NN N N N V N 2 N V N V N N 2 N N N N 3% Nx z N
VN N N N N N N N N N N V N 2 N 2 N N 22:2 5 Nx z N
a N N N N N V N N2 N2 N N N N2 NN N N N 2.3% x z N
NN2 N N N V 2 N N V2 NN N N2 N2 N V N N N 222% _ z N
NN 2 N N 2 N N 2 N N2 V N N V N N N N 3% Nx N N
NN N N N N 2 N 2 N N N N 2 2 V N 2 N 22:8 28 Nx N N
N 2 N 2 N N 2 V N N N V N N N2 2 N N 29222 x N N
NN N N N N 2 2 N N N2 N V V N NN N N N 222% _ N N
N: N 2 N N N N N N NN NN 22 N N NN 2 N N 2&5 Nx 2s 2
NV N N N 2 N N N N N N2 V N N N N N N «:85 Nx 2s 2
NN2 N 2 N N 2 N N NN NN 2V NN N2 N NN N N N Nana x 22 2
NN2 2 N 2 N N N N NN NN N2 N N N N N N N 2822 _ 2s 2
E N 2 2 N 2 2 NN NN NN N2 N N V N N N N 3% Nx N 2
NN N N N N N N N NN N N N N2 N N N N N N85 Nx N 2
NN2 2 N N N N N N N N2 N2 N N2 N NN N N N 296 x N 2
NN2 N N 2 N N N N N2 NN N2 V2 NN NN NV NN N N Nana _ N 2
NN N N N N N 2 N N N N N N N N2 V N N 58. Nx z 2
NN N N N N N 2 N N2 NN N2 N N N N N N N NNNN Nx z 2
NN N N N N 2 N N V N2 V V N2 N2 N N N N 2822. x z 2
NN2 N N N 2 N N N2 NN 2N N2 N VN N 2N N N N 222% _ z 2
NN N N N 2 N N N N N N N N N N 2 N N «.85 Nx N 2
E N N N N 2 N N N N 22 N N V N N 2 N N85 Nx N 2
VN N N N N N N N V2 N2 N N N N N2 V 2 N 222% x N 2
NN N N N N N N N N2 N2 N2 N N N VN N N N 295 _ N 2
.5; 2NVN NNNN NNNN NNNN 22x22 NNN2 NNN2 NNN2 NNV2 NNN2 NV: NNN2 NNN 22N VNV NNN 2NN §z£ 95 5:
232.222 Nan—«N .322 Nahum—2 :23 .28 6252—3 22305.3. 352— .222 22.2.2222 25332522222 92,—.

 

.33 .803 .2222? :2 N253? ENEMwNSNE 2822 0322222282.. Em? 05 :2 2202.222 29228 05 No 2225 05 N 2223222822822 23:
Eon NNNDV >26 Eamon .3 2282298222 2202.222 295% some 28 :28 mm: 2222va 352% SNNQNNENV 225022.232 880m 30H 6.0 «322,—.

100

APPENDIX C

 

NNN N N N 2 N N V NV NN2 NN NV NV N N N N N 2N2_N2_N Nx 2 V
VV N N N 2 2 22 N N 22 V N N N 2 N N N 222.3 N_ Nx 2 V
NN N 2 N 2 N V N N N2 N V N N N V N N 222% x 2 V
NN2 N N N 2 N V N N NV V2 N N N V2 2 N N N38 .2 V
NN N N N N N N N N N 22 N N V N N N N 933 Nx N V
N N N N N N N N 2 N N N N 2 N 2 N N 858 so Nx N V
NN N N N N N N N V N N N N 2 N2 N N N 2qu x N V
VN N N N N 2 N N N N2 N2 N V N V N N N 2.2% _ N V
NNN N N 2 N2 N N 22 N2 NN NV NN N N2 N2 N N N 222% Nx 22 N
NN N N 2 N N N 2 V N N2 N N N N N N N N85 Nx 22 N
V2 N N N N 2 N N 2 N V N N N V N N N 286 x 22 N
NN N N N N N N N 2 V N N N N N2 N N N 0.22% :s N
NN N 2 N N 2 V N 2 N2 N 22 N N2 N N N N Nana. Nx N N
NN N N N N N N 2 N N2 N 2 N N N N N N «.35 Nx N N
NV N N 2 2 N N N N V V2 N N N N N 2 N 222% x N N
NN N N N N 2 N N N V2 N2 V V N2 N N N N 2.2% _ N N
VN N N N N N N N 2 V2 N N NN N2 N N N N E8 Nx z N
s N N N N 2 2 N N 2N N2 N N N N N 2 N 8% Nx z N
V N N N N N N N N N N N 2 N N2 N N N 222% x z N
NN2 N N N N N 2 N N N2 22 N N N2 VV N N N 293 .z N
NN N N N N N N N N N N N VN N2 N 2 2 N 58 Nx N N
NN N N N N N 2 N 2 N N N 22 N V2 2 2 N 58 Nx N N
VN N N N N N N N N N N N N V2 N2 2 N N 293 x N N
NN N N N N 2 2 N 22 N2 VN N N V N2 N N N 2N8 _ N N
NN 2 N N N 2 N N N N V N N N V N N N 3% Nx 22 N
NN N N N N 2 2 N N N N N 2 N2 N 2 N N .255 :5 Nx 22 N
NNN N N N 2 V N N NN NV 2N N2 NN N NN N N N 222% x 22 N
NNN N 2 N N N N2 N N NN N2 NN NN N2 2V V N N 222% :5 N
NN N 2 N N N 2 N N N N N N V N N 2 N 2228 Nx N N
VN N N N N N N 2 N N N N N N N N N N 5:22 N_ Nx N N
8 N N N N 2 N V N N2 N2 N 22 N NN N N N 222% x N N
.55 2NVN NNNN NNNN NNNN 2N2: NNN2 NN: NNN2 NNV2 NNN2 NV: 83 NNN 22N VNV NNN 2NN 52%: NE .NE

 

62:23.30 .10 93.28

101

Table C.4. Continued.

 

1435 1632 1756 1856 1961 2056 2220 2395 2451 Total

261 357 454 611 767 1009 1147 1293

Habitat

Plot Trap

 

17

11

0
0
0
0
0
0
0

1

apple
apple

in barrier

48X

77

13

13

16

17
67

SX2
4 SX3
4 WI
4 WX

4

1 4
24
35

11
14
10

apple
apple
apple

88
146

11

11

25

10 17

15

26
67

4 WX2 out barrier

4 WX3

34
13
19

11
11

13

com
apple

apple

96
86
22
56
68

10

19

027
626

0
0

0
0
0

El

EX

EX2 out barrier
EX3
5 NI

5
5

APPENDIX C

1 10 15 11 16
10

0

corn
apple

11 16

15

0

OVOONWO—‘O l‘
22NVVN2a222§§33338
OOOOOOOOOOOOOOOCOO

v-V'COv-OOv-COPOOCOOCDOQNO)
v-v- NN
VGVOMFQQVOOOIDOCCDIOM
'- VCO GOV-N
ONGFVVFQNONVNOPQQF
1-1- Nv- 1-
CONNODFl-DCIBNCDOONOJMMNVCD
Pv-OOOv-OLOVNOI-NEIOOOv-v—N
F
DOFPMNQCQCNNSMOMNCD
1- N!— v-(Ov-v- 1-
NOONNv—OOPOOFOPLDNVO
‘-
OOOOMOOO Ov- OPOv-OO
OPOOOOCOOFOOOOOCOO
91" 22“”22“m225522m
a-ggqn-ggaa-g'gaaﬁﬁaa”
ea~eeaaaeamee==ee9
no .0; .03 “I“ or
.E .E ‘5
O
NCO NC 010‘) gm N
XXX—XXX—XXX—X X—XX
IDIOMI-Ol-DIDIOIDUDIDIDCD CDCOCDCDCD

102

Table C.4. Continued.

 

1435 1632 1756 1856 1961 2056 2220 2395 2451 Total

1293

261 357 454 611 767 1009 1147

Habitat

Plot Trap

 

15
90
28

0
0
0
0

grass

6 NX3

31 12

16

apple
apple
grass

l
SX
SX2
SX3
6 WI
6 WX
6 WX2
6 WX3

35

6
6

58
130

19
35

com
apple
apple
grass

15

33
21

17
15

0
0
0
0
0
0

110

26

15

35

12

24
162

grass

40
25

61

11

22
6 34

apple
apple
aﬂaﬂa
weeds

E |

7

113

17

16

0

EX
EX2
EX3

N l

APPENDIX C

\OMVIOVIO

[\WWOOOM
F-I

DOV-COO

mommNtx
‘— Vv-N
NNCDCOINN
N 1.01-1-

14
24
18
18
4
1

0
0
0
0
0
0

apple
apple
grass
grass

NX
7 NX2
7 NX3

103

0 212

0

11

44
19

71

25
22

31

0
0
0
0
0
0
0

apple
apple
grass

SI

97

23

13

SX

26
35
260
204

SX2
SX3
7 WI
7 WX
7 WX2
7 WX3

14
57

grass

NNNN

8 10 22 100

41

apple
apple
grass

87

17
20

16

61

0

16
18
24
23
17

49

11

oak
apple
apple

92

18
10

23
10

0
0
0
0
0
0

El

8
8

89
45

10

EX

E X2 out barrier

45

27
10

aﬂaﬂa

EX3

8

89
55

15 37

12
14

apple
apple

NX

10

APPENDIX C

 

 

NN N N N N N N N N NN N2 N2 N N N N N N 2:8 Nx 3 N
NN N N N N N N N N NN N 2 N N N 2 N N 22.828 Nx 22 N
NN2 2 N N 2 N N V N NN N2 N 22 N V N 2 N 22.8 x; N
NV2 N N N N N V N 22 2N N2 N2 N2 N N2 N N N 22.8 :s N
NN N N N N N N 2 N N N N N N N N N N 3% Nx N N
_V N 2 N N N N N N VN 2 2 N N N N N N 222.2 N_ Nx N N
NN N N N 2 2 N N N NN N N2 N V N N N N 2qu x N N
N: N N N N N N 2 2 NN NN N N N N N N N 20.92. _N N
2 N N 2 N N 2 N 2 N N V 2 2 N N N N NNNNN Nx z N
N N N N 2 N N N N 2 2 2 N N N N N N 553 N_ Nx z N
25°F 2NVN NNNN NNNN NNNN 2NN2 NNN2 NN: NNN2 NNV2 NNN2 NV22 NNN2 NNN 22N VNV NNN 2NN 233...: NNN: 35

 

62:52:20 6.0 035,—.

104

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