THE BIONOMICS 0F PLATYNOTA IDAEUSALIS
(Lepidoptera: Tortricidae) ilN MICHIGAN

Thesis for the Degree of M. S.

MlCHlGAN STATE UNIVERSITY

HENRY WILUAM HOGMIRE, JR.
1976

---—........'-—1=.

ABSTRACT

The tufted apple bud moth, Platynota idaeusalis (Walker)

 

(Lepidoptera: Tbrtricidae), has 2 generations per year in
southwestern Michigan apple orchards. Most abundant in Berrien
Co., populations rapidly diminish as one proceeds northward.
The appearance of percentages of the adult male population is
predicted based on day-degree accumulations. Variation between
orchard locations occurs, with more day-degrees being accumu-
lated at corresponding population percentages as one moves
inland (east) from Lake Michigan. The adult male is active
throughout the night with peak flight occurring between 12 p.m.-
4 a.m. An insignificant number of larvae are parasitized by

the braconid parasitoid, Microgaster pantographae Muesebeck.

 

'Windsor' and 'Schmidt' sweet cherry varieties serve as

additional hosts.

THE BIONOMICS OF PLATYNOTA IDAEUSALIS

 

(Lepidoptera: Tortricidae) IN MICHIGAN

BY

Henry William Hogmire, Jr.

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Entomology

1976

ACKNOWLEDGEMENTS

The author wishes to express sincere appreciation to
Dr. Angus J. Howitt for his guidance and support, and for
providing the rewarding opportunity to work at the Trevor
Nichols Farm. The author thanks the Department of Entomology
for providing financial assistance during the course of this
study, and to Drs. Frederick W. Stehr, Robert F. Ruppel and
James E. Moulton for their services on the guidance committee.

The author is grateful to Dr. J. F. Gates Clarke and
Mr. Peter Martinat for their identification of collected
material; Mr. Larry Olsen and his field scouts for their aid
with the distribution study; Mr. Sam Jennings for his help
with the linear regression analysis; Mr. Vic Friday, Mr.
George Shane, and Mr. John Page for the use of their orchards
during the course of this study; and to Dr. Ray Kriner,
Extension Entomologist at Rutgers University, for the use of
figures 33 and 36.

A very special thanks is extended to Mr. Alfred Pshea
for his assistance in familiarizing the author with fruit

pests and orchard practices.

ii

TABLE OF CONTENTS

LIST OF TABLES
LIST OF FIGURES
INTRODUCTION

DESCRIPTION OF STAGES

E99
Larva

Pupa
Adult
LIFE HISTORY
PHEROMONE
CONTROL
EXPERIMENTAL METHODS AND MATERIALS
RESULTS AND DISCUSSION
A. Pheromone Monitoring
B. Seasonal Appearance Based on Day-Degrees
C. Seasonal Development
D. Alternate Hosts
E. Adult Male Flight Activity
F. Natural Enemies
G. Larval Key

CONCLUSIONS AND RECOMMENDATIONS

LITERATURE CITED

iii

Page

iv

0‘

\TQO‘O‘

10

16

16

16

38

4O

41

41

44

46

50

LIST OF TABLES

Page
Table l. - Pheromone monitoring sites. 10
Table 2. - Total adult male pherocatch/3 Sectar
tent traps. 25
Table 3. - Estimated percentages of the total adult
male population at accumulated day-degrees (Base 48°F). 37
Table 4. - Hourly timing trap pherocatch,
temperature, and relative humidity. 42

iv

LI ST OF P IGURES

Figure l. - Collecting sites of Platynota idaeusalis
in Michigan, 1974-1975.

 

Figures 2 through 15. - Pheromone monitoring of
adult male population at 8 southwestern
Michigan orchard locations, 1974-1975.

Figures 16 through 25. - Seasonal appearance of
percentages of the adult male population on day-degrees

at 5 southwestern Michigan orchard locations, 1974-1975.

Figure 26. - Seasonal development of E; idaeusalis,
Coloma, Mich., 1974.

 

Figure 27. - Adult male hourly flight activity.

Figures 28 through 33. - The developmental
stages of g; idaeusalis.

 

Figures 34 through 36. - Foliage and
fruit injury.

Figures 37 and 38. - Pheromone trapping devices.

Figure 39. - Braconid parasitoid.

Page

18

27

39

43

48

49
49

49

INTRODUCTION

Platynota idaeusalis (Walker) was originally described
by Clemens (1860) as §;_sentana and was redescribed by Robinson

(1869) using the scientific name of TOrtrix sentana.

 

This tortricid has been labeled as a general feeder.

Fernald (1882) lists black haw (Viburnum prunifolium) and blood

 

root (Sanguinaria sp.) as food plants. Mr. August Busck (Frost,
1923), of the United States National Museum, has unpublished
records of larval feeding on blackberry (Rubus sp.), osage
orange (Maclura pomifer), golden rod (Solidago sp.) and aspen
(Populus sp.). Additional reported food plants include apple
(M312§>sp.) (Frost, 1923), Solanum and clover (Trifolium sp.)
(Forbes, 1923) and Vaccinium (MacKay, 1962). Bode (1975), by
examining plants underneath apple trees, discovered larvae

feeding on slender knotweed (Polygonum aviculare), dewberry

 

(Rubus villbsus), yellow toadflax (Linaria vulgaris), Pennsyl-

 

vania smartweed (Polygonum pennsylvanicum), common dandelion

(Thréxacum officinéle), horsenettle (Solanum carolinénse),

 

alfalfa (Medicago sativa), nimblewill (Muhlenbergia schreberi),

 

bindweed (Convolvulus sp.), smooth crabgrass (Digitaria

ischaemum), birdsfoot trefoil (Lotus corniculétus), white

 

clover (Trifolium répens), green foxtail (Setaria viridis),

 

wild strawberry (Fragaria virginiana) and Virginia creeper
(Psédera sp.).

§;_idaeusalis is found along the atlantic coast from

 

Nova Scotia to Florida, west to Manitoba and Texas, and in
Washington and British Columbia. Distribution probably occurs
throughout the northern United States and Canada (Fernald 1882,
U.S.D.A. 1959, MacKay 1962).

This insect was first reported as an economic problem
in Pennsylvania apple orchards by Frost (1921a, 1921b).

Larvae were reported feeding in orchards during late May and
early June, and again in the fall. Considerable injury was
reported from Erie, Blair and Adams counties, Pennsylvania
(Frost 1942, 1951).

The insect museum at Michigan State University has
specimens and Michigan records from the counties of Charlevoix,
Otsego, Montmorency, Oscoda, Midland, St. Clair, Oakland,
Livingston, Washtenaw, Wayne, and Berrien (starred counties
in Figure l). The presence of significant populations of
E; idaeusalis in Michigan apple orchards was first realized
in 1973 with the use of a pheromone (synthetic chemical
attractant) produced by the Zoecon Corporation. Field scouts
working for the Michigan Cooperative Pilot Apple Pest

Management Program found P;_idaeusalis present in 143 orchards

 

throughout the fruitbelt of Michigan from Berrien to Benzie
counties (Figure l). The species was identified by Dr. J. F.
Gates Clarke* from 30 adult male specimens obtained by

pheromone trapping.

 

*Dr. J. F. Gates Clarke is a Research Associate in Lepidoptera
at the Smithsonian Institution, Washington, D. C.

As a result of this insect's reported economic importance
in Pennsylvania, and its wide distribution throughout Michigan's
fruitbelt, a study was conducted to determine the biology and

pest status of P; idaeusalis in Michigan.

 

Figure l. - Collecting sites of Platynota idaeusalis

 

in Michigan, 1974-1975.

O==3 or more locations.
-= 1 location.

'*==insect museum records.

 

 

 

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Description of Stages

 

Egg

The eggs (Figure 28) are laid in patches of 100 or slightly
more overlapping eggs which are covered with a milky-white
translucent envelope. Initially apple green in color, these
masses change to a copper color, and finally to a black head
capsule stage prior to hatching (Frost, 1923). The incubation
period ranged from 10-14 days for both spring (June, July)

and summer (August, September) generations in 1974.

Larva

First instar larvae are 1.5-2.0 mm long, have a head
capsule width of .20 mm, and are yellowish in color with a
dark brown to black head and prothoracic shield. Larvae
mature through 5 instars, with the last instar having a
length of 13*18 mm and an average head capsule width of
1.21 mm. Mature larvae (Figure 29) are brown, rarely olive,
in color with a chestnut brown head and prothoracic shield.
The prothoracic shield is lighter colored anteriorly with
some darker brown overlay on the posterior margin. Each
body segment has 4 dorsal, silver-colored pinacula which are
raised, thus giving the body a warty appearance (Frost, 1923).
MacKay (1962) reports that the body may also bear vague,
pale, longitudinal stripes (Figure 30). The last segment
possesses a 6-9 pronged anal comb (Figure 31) which according
to Frost (1919) is used to propel frass pellets away from

the larva's body.

Pupa
The pupa (Figure 32) is reddish-brown, about 13-15 mm

long; the adult emerges in 9-11 days (Frost, 1923).

Adult

The adult (Figure 33) is small, usually less than 12 mm
in length, and is inconspicuously patterned with various
shades of gray and brown scales. Forbes (1923) describes
the adult as ash gray, irregularly shaded with blackish and
dull brown with raised black striae. The male tends to have
a pale outer wing margin with 2 or 3 fine striae. The female
has a pale basal half, slightly broader than the male's,
with an oblique black stria across the middle of the wing.
The hind wing in both sexes is grayish-brown. The tips of
the forewings are ribbed longitudinally and possess 2 or 3
groups of erected scales which give the insect its common

name; tufted apple bud moth.

Life History

 

The winter is passed as immature larvae webbed in dead
leaves of the previous season on the orchard floor (Frost,
1923). Early in the spring, about bud swell, these larvae
crawl up the trunk and seek out the opening buds of apple
where they feed on developing leaves, often burrowing in the
petioles or chewing the blossoms. Bode (1975) believes
that the overwintering larvae complete their development

on ground vegetation. The author's research revealed that

either situation may occur depending on the availability of
ground vegetation.

Frost (1923) found that 2 flights of adults occurred
under Pennsylvania conditions; the first in late May and
early June, and the second in August and September. Forbes
(1923) believes adults are on the wing from June to August.
Bode (1975), via pheromone trapping, found male moths from
overwintering larvae to be active from early May to mid-July,
with a second flight occurring from mid-July into October.
Prentice (1965) found adults to be active from late June to
mid-July in Canada. While Frost's and Bode's reports suggest

that P;_idaeusalis is bivoltine under Pennsylvania conditions,

 

Asquith (Chapman and Lienk, 1971) believes this species to
be univoltine in Pennsylvania. Life history studies in
Michigan support Frost's and Bode's findings.

Frost (1923) reports that g; idaeusalis is very similar

 

to the eye-spotted bud moth, Spilonota ocellana Denis and

 

Schiffermuller, in its habits and manner of feeding, and
that the injuries caused by these 2 species are indistinguish-

able. Forbes (1923) reports that the larvae of P;_idaeusalis

 

are frequently found webbed within a folded leaf or between
2 leaves. The larvae chew part way through the petiole of
a leaf and then feed on this hanging leaf webbed within a
lengthwise fold (Figure 34). Feeding continues even though
the leaf becomes dried and withered from the petiole damage.

Asquith (Chapman and Lienk, 1971) reports that the most

typical feeding site occurs where a larva has cut a leaf and
fastened it with webbing to the side of an apple (Figure 35),
thus allowing the larva to feed on both in relative seclusion.
Damage to the fruit is characterized as shallow, irregular,

surface excavations (Figure 36).

Pheromone
Roelofs and Comeau (1971) found trans-ll-tetradecenyl
alcohol to be an attractant for the male tufted apple bud moth.
A pheromone consisting of this compound plus a synergist,
trans-ll-tetradecenyl acetate, was produced by the Zoecon
Corporation in 1973, thus providing a monitoring tool for

the adult male population.

Control
Bode (1975) advocates control through the use of properly
timed sprays at intervals of 7-9 days during the 2 critical
periods of oviposition and egg hatch. He also suggests that
a delayed-dormant spray of oil plus insecticide be directed
onto the ground beneath the trees in an effort to reduce over-

wintering larval populations in orchards where g; idaeusalis

 

is a problem.

10

EXPERIMENTAL METHODS AND MATERIALS

Pheromone Monitoring.

The adult male population was monitored with the use

Figures 2-15) during 1974-1975.

Table l. - Pheromone monitoring sites.

of a pheromone (synthetic chemical attractant) at 8

southwestern Michigan apple orchard locations (Table 1,

 

Orchard Location

Orchard Status

Apple Varieties

 

Berrien Co.

Coloma, Mich.
Watervliet, Mich.

Van Buren Co.

Bangor, Mich.

Kalamazoo Co.

Kalamazoo, Mich.

Richland, Mich.

Allegan Co.

Fennville, Mich.

Douglas, Mich.

Barry Co.

Hickory Corners, Mich.

*Sprayed
Sprayed

Unsprayed

Unsprayed

Unsprayed

Unsprayed

Unsprayed

Unsprayed

Chenango, Jonathan
Jonathan, McIntosh

Jonathan, Red Delicious

Jonathan, Northern Spy,
Rhode Island Greening,
Red Delicious

McIntosh, Northern Spy,
Jonathan, Snow, Wealthy

McIntosh,
Jonathan

Northern Spy,

Jonathan, Red Delicious

Winesap

Jonathan, Red Delicious

 

*
Insecticide Application.

11

Rubber septums containing the pheromone (trans-ll-tetra-
decenyl alcohol plus trans—ll-tetradecenyl acetate) were
purchased from the Zoecon Corporation. A single septum was
placed in a Sectar(:)commercia1 tent trap from 3M (Figure 37)
which had been purchased pre-coated with a sticky substance.

As a result, male moths which were attracted to the pheromone
and which entered the trap, were caught. Three traps (l trap/
tree) were hung about 5-6 feet high in each of the orchard
locations. Each trap was separated by a minimum of 2 tree
spaces. Traps were placed in the orchards during the first
week of May and removed during the latter part of October after
the moth catch had reached and remained at zero for 2 weeks.
Each trap was checked once a week on the same day, with the
moths being removed and counted. When high moth catches were
obtained, the trap was removed and replaced with a new trap.
The rubber septums, which last 6-8 weeks, were replaced every

5 weeks to ensure adequate pheromone concentration and trapping

efficiency.

B. Seasonal Appearance Based on Day-Degrees.

Day-degrees were accumulated (equations for calculations
provided by Ruppel, 1974) from January 1 until the end of
emergence so that the seasonal appearance of percentages of
the adult male population could be predicted. Samples were
collected by pheromone trapping utilizing the data obtained

from the 3 traps described above. Data were obtained from

12

4 orchard sites in 1974, and the same 4 plus 1 additional
site in 1975. Maximum and minimum daily temperatures were

collected for both years from the nearest recording weather

 

 

station.
Orchard Site Weather Station
Coloma, Mich. Watervliet, Mich.
Watervliet, Mich. " "
Bangor, Mich. Bloomingdale, Mich.
Kalamazoo, Mich. Kalamazoo State Hospital
Richland, Mich. Gull Lake Biological Station

A base developmental temperature of 48°F (9°C) and an
upper threshold limit of 86°F (30°C) were used. Fahrenheit
temperatures were utilized in calculations since weather
stations record daily maximum and minimum temperatures in
these units. Day-degrees were computed and accumulated
daily by using the equation:

_ max. temp. + min. temp. _
DD48 - 2 48.

 

Sine-wave correction tables (Gage and Haynes, 1974) were used
to calculate the day-degrees when the minimum temperature
fell below the base temperature. The area under the curve
represented by each sample was computed with the equation:

A = am + N_l)

 

2
where d is the difference in accumulated day-degrees between
the date sampled and the previous date sampled; N is the sample

size and N-1 is the previous sample size. The sample areas

13

were summed (SA) and the percent of the total area represented
by the area for each sample was calculated by the equation:

A
% = lOOzag)

The percentages were accumulated for each location for each
year, and then transformed (tables used) to logistic units
for linear regression analysis. The data for all locations
and for both years were pooled for the final regression
analysis. The computed sigmoid curves for both spring and
summer generations were graphed (Figures 16-25) and the

observed data were added as points on the graph.

C. Seasonal Development.

The seasonal development of both generations of P; idaeusalis

 

was monitored in a 15 acre mixed block of Chenango and Jonathan

apple varieties near Coloma, Mich. in 1974. The adult male

population was monitored by pheromone trapping (See Section

A above), with data on other life stages obtained by making

field observations and through rearing under orchard conditions.
Adult moths were captured on the trunks of apple trees,

and both sexes were released into a 3x3x3 wooden and wire

screened cage containing apple seedlings. The life history

of the progeny from these adults was then studied. Some of

the larvae obtained from the orchard were also placed on

seedlings so development and feeding behavior could be observed.

Apple seedlings were watered every 2 days and replaced as

needed. Egg masses and pupae were marked in the orchard with

14

red ribbon so hatch and emergence could be monitored.

D. Alternate Hosts.
A variety of both tree and small fruits were investigated

for the presence of P;_idaeusalis life stages. The presence

 

of the adult male was investigated by pheromone trapping in

a 4 acre block of Montmorency tart cherries near New Era,
Mich., 10 acres of Windsor and Schmidt sweet cherry varieties
near Coloma, Mich., and a 1.5 acre patch of Jersey blueberries
near Grand Junction, Mich. These same locations plus a 3

acre block of Redhaven peaches and a 5 acre field of Midway
strawberries near Coloma, Mich. were investigated for the

presence of other life stages.

E. Adult MaleFlight Activity.

The flight activity of the adult male was monitored
using an hourly timing trap (Figure 38). This trap was placed
in a 10 acre mixed block of Windsor and Schmidt sweet cherry
varieties near Coloma, Mich. where larval feeding had been
observed in the spring of 1975. This trap provided a 12-
hour sampling period, with each hourly sample being caught
in a separate compartment on a revolving cylinder which was
coated with Stickem Special(:). Moths were attracted to the
timing trap by the use of a pheromone capsule suspended above
the revolving cylinder. Samples were taken for a 12 day
period (August 18-29) from 7 p.m. - 7 a.m., E.D.T. Captured

moths were counted and removed every morning with additional

15

Stickem Special®being added as needed. The hourly temper-
ature and relative humidity were recorded using a hygrother-

mograph.

F. Natural Enemies.

Folded apple leaves containing parasitoid pupae were
placed in 4" diameter petri dishes along with some moistened
cotton to prevent desiccation. These petri dishes were placed
in an environmental chamber which was maintained at a temper-
ature of 75°F and 80-90% relative humidity. Adult specimens

were delivered to Mr. Peter Martinat* for identification.

G. Larval Key.
A last instar larval key was developed to distinguish

living specimens of §;_idaeusalis from 7 other tortricids

 

commonly found in Michigan apple orchards. Morphological
observations were made on specimens obtained from the field
as well as those reared on apple seedlings under controlled
laboratory conditions (temperature 75°F, 80-90% relative

humidity).

* Mr. Peter Martinat is a graduate student in taxonomy at
Michigan State University.

16

RESULTS AND DI SCUS S ION

A. Pheromone Monitoring.

Figures 2-15 show the results of the pheromone monitoring
at 8 orchard sites during 1974-1975. Two generations were
found to occur in all locations except Douglas, Mich. where
only a single generation was discovered. This may be due
to the proximity of Lake Michigan (1.5 mi.) to the Douglas
orchard which delays seasonal development. However, at the
Fennville orchard site which is only 3.5 miles from Lake
Michigan, a second generation was found to occur but even
here the number of moths caught was quite minimal. .3;

idaeusalis was found to be most abundant in Berrien Co. A

 

significant reduction in numbers of moths caught is observed

as one proceeds in a northern and eastern direction from

the southwestern corner of the state. At the 6 orchard sites
where trapping was conducted both years, the number of adult
males caught in 1975 was considerably less than that obtained
in 1974 (Table 2). No explanation for the trap catch reduction

in 1975 can be given.

B. Seasonal Appearance Based on Day-Degrees.

A good correlation (Figures 16-25) was found to exist
between the seasonal appearance of percentages of the adult
male population and accumulated day-degrees. The coefficient
of correlation ranged from .960-.999 for both spring and

summer generations. Table 3 reveals that the appearance

17

Figures 2-15. - Pheromone monitoring of adult male population
at 8 southwestern Michigan orchard
locations, 1974-1975.

18

200 '

IOO'

@ Coloma, Mlch. l974
"/f

100- y

l40 "

U

I20

IOO

 

 

 

 

.L

l42l28 4 II l825 2 9 l62330 6 {32027 3 IO|724 I 8 l5

Total phorocatch I 3 Sector tam traps

 

May June July Aug. Sept. Oct .
I00 P Q) I Coloma, Mich. IS":
80 b
60 "
4o -
20 1- \‘“'\

 

 

 

O
6 l32027 3 IO l724 I 8 l52229 6 l2|926 2 9 ”2330
May June July Aug. Sept.

Total phorocatch / 3 Scctat tcnt trap:

19

I20 6) Watervliet, Mich. I974

60 ‘
cor

2:»   s L

I I 4 II l826 2 9 l62330 6 I62027 3 l0 l724l 8 I6
May June July - Aug. Sept. Oct.

 

 

 

WatervIIct, MlclI. I976

     

11am L11L1L\.’

6 I6 2027 3 I0 I? 24 I 0 I6 2229 6 I2 I926 2 9 I62330
May June July Aug. Sept.

Total p‘horocatch/ 3 Sector tent traps

60'

60"

40"

N
O
I

3
I

 

20

Richlond .Mich. I974 H

 

 

 

K

I l I l 1 1 l 1 j l

01 1:51—4—0
I42I 28 4 II I825 2 9I6233O 6 I32027 3 IO I7 24 I 8 I5

May June July Au g. Sept. Oct.

0
O

.5
0

(II

N
O

 

03

Richland, Mich. I975

®

. -. . z I2|9262 9|623O
May Juno July Aug. Sept.

21

Kalamazoo, Mich. I974

to
‘3
O

 

 

 

 

 

I6
IO
2 a
E
.. O . . .
5 I42l 264 II I626 2 9 I6233O 6 I32027 3 IO I724 I 6 I6
‘3' May June July Aug. Sept. Oct.
8
a:
no
\
B
2
O
0
O
h
0
'5. 20- .
'3 A Kalamazoo, Much. I976
.2 I6 r
w-
a . LA My
0 l ‘ 1 1 1 1 l 1 Ad- l

 

 

6 I32027 3 IO I724 I 6 I62229 6 I2 I926 2 9 I6233O
May June July Aug. Sept.

Total phorocotchl 3 Soctar toot trap:

20

IO

22

Fannyillo, Mich. I974

 

 

O
I42I 26 4 II I626 2 9 I62330 6 I32027 3 IO I724 I 6 I6

May June July Aug. Sept. Oct.

Fonnvillo, Mich. |976

 

I6r
®
I0-
6"
011: 11111\"11an

 

6 I32027 3 IO I724 I 6 I62229 6 I2 I926 2 9 I6233O
May June July Aug. Sept.

Total phorocotch I 3 Sector tent traps

(I
O

N
O

3

20

IO

9
®

23

Douglas, Mich. I974

  

 

L1

0 a a L a l a a 14
I42I26 4 II I626 2 9 I6236O 6 I32027 3 IO I724 I 6 I6

 

 

May June July Aug. Sept. Oct.
' ® Douglas,Mich. I976
- " z .2229 5 I2 I926 2 9 I6233O

May June July Aug . Scpt .

Total phorocatch I 3 Scott! tent trap:

24

Hickory Cornorc, Mich. I974

a

N
O
I

 

/\l

0-.

5
6

 

 

o t
I 2| 284 II I826 2 9 I623306 I32027 3 I0 I724 I 8 I3
May Juno July Aug. Sept. Oct.

 

 

 

70

® Bangor, Mich. I976
60
60
4o
30
20
| A

At- A
6 l62027 6 IOI724 I 6I62229 6 I2 I926 2 9 I62330

May Juno July Aug. Sept.

25

Table 2. - Total adult male pherocatch/3 Sectar tent traps.

 

 

 

Location 1974 1975 % Reduction in 1975
Coloma, Mich. 918 410 55.3
watervliet, Mich. 471 294 37.6
Richland, Mich. 205 159 22.4
Kalamazoo, Mich. 122 65 46.7
Fennville, Mich. 68 42 38.2

Douglas, Mich. 95 64 32.6

 

26

Figures 16-25. - Seasonal appearance of percentages of the
adult male population on day-degrees at 5

southwestern Michigan orchard locations,
1974-1975.

- Coloma, Mich. -| 974

27

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Table 3. - Estimated percentages of the total adult male
population at accumulated day-degrees (Base 48°F).

 

 

 

Location Year Generation 10% 50% 90%
Berrien Co.
Coloma, Mich. 1974 Spring 568 818 1068
Summer 2056 2300 2544
1975 Spring 441 685 928
Summer 2009 2280 2551
watervliet, Mich. 1974 Spring 505 731 957
Summer 2061 2311 2561
1975 Spring 437 687 937
Summer 2076 2332 2589
Van Buren Co.
Bangor, Mich. 1975 Spring 598 819 1040
Summer 2206 2346 2485
Kalamazoo Co.
Kalamazoo, Mich. 1974 Spring 761 1100 1439
Summer 2322 2578 2835
1975 Spring 691 988 1284
Summer 2303 2567 2831
Richland, Mich. 1974 Spring 676 926 1176
Summer 2332 2485 2639
1975 Spring 634 906 1177
Summer 2323 2521 2719
Southwestern, Mich. 1974-1975 Spring 574 853 1132
(All locations pooled) Summer 2093 2421 2748

 

38

of corresponding percentages of the adult male population
occurred earliest in Berrien Co., with more day-degrees being
accumulated as one proceeds farther inland (Van Buren and
Kalamazoo Cos.) from the lakeshore. A difference is also
noted between 1974 and 1975 with respect to the day-degrees
accumulated at respective population percentages. In almost
all instances, the appearance of 10, 50 and 90% of the
population occurred at earlier day-degree accumulations in
1975 than in 1974.

Differences encountered between orchard locations and
years with respect to day-degrees accumulated at given
population percentages cannot be fully explained. Only 1
environmental parameter, air temperature, is utilized as a
predictive tool. Other parameters such as soil temperature
and rainfall can be very influential factors as regulators
of insect development. For example, Miller*, working with
Diaparsis sp., has found that the appearance of given
population percentages occurs at greater day-degree accumula-
tions when rainfall increases. This ichneumonid parasitoid
overwinters in the soil as a prepupa within the cereal leaf

beetle cocoon.
C. Seasonal Development.

Figure 26 shows the seasonal development of the life

* Mr. Dave Miller is a graduate student in the Department
of Entomology, Michigan State University.

39

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40

stages of §:_idaeusalis at Coloma, Mich. during 1974. The
monthly (upper horizontal axis) occurrence of life stages
is plotted, with the corresponding monthly day-degree
accumulations appearing on the lower horizontal axis.

Egg masses were found to be deposited on the upper
surface of leaves on scaffold limbs near the trunk of the
tree. Overwintering larvae were found maturing on ground
apple sucker growth early in the spring. Newly hatched
larvae disperse and web themselves in with an abundance of
silken threads on the undersurface of the leaf. This silken
chamber is usually situated along the midrib or other large
vein. Larvae were also found webbed between 2 leaves. Later
instar larvae were found webbed within a lengthwise fold of
a hanging leaf which had been clipped at the petiole. Fruit
feeding was quite minimal and consisted of shallow, surface
feeding beneath a leaf which had been webbed to the side of
the apple. Adults of both sexes were observed during the

day resting on the tree trunks near the ground.

D. Alternate Hosts.

Pheromone trapping revealed the presence of the adult
male in all areas sampled. However, this does not imply
that the particular fruit investigated is utilized as a host
but merely that the insect is present in the vicinity or
possibly on ground vegetation within the crop investigated.

Eggs were found deposited on the upper leaf surface, trunk,

41

and scaffold limbs of the sweet cherry varieties studied near
Coloma, Mich. Larval feeding was observed on the foliage

of sweet cherry in the tree, as well as on dead and withered
leaves on the ground beneath the trees. However, no feeding
was observed on tart cherry or on blueberry. A closely

related insect, the variegated leafroller, Platynota flavedana

 

Clemens, was discovered feeding on the foliage of Midway
strawberries, and on both the foliage and fruit of Redhaven

peaches near Coloma, Mich.

E. Adult Male Flight Activity.

Table 4 shows the hourly moth catch along with the hourly
temperature and relative humidity. The temperature was not
recorded on August 25-26 due to a malfunctioning of the
temperature recording needle on the hygrothermograph. Male
moths were found to be active throughout the night from
9 p.m. - 7 a.m., E.D.T. the next morning. The peak flight
activity occurred between 12 p.m. - 4 a.m. (Figure 27) with
63.5% of the total catch occurring during this time interval.
Relatively little activity was observed during the early
morning hours of August 19 and 27. In both cases the temper-
ature ranged from 60-62°F. It appears that 62°F may be an
activity threshold for the male moth as no other climatic

conditions which might explain this inactivity could be found.

F. Natural Enemies.

A total of only 4 parasitized larvae were discovered

Table 4. - Hourly timing trap pherocatch, temperature

and relative humidity.

Time (EDT)

 

 

P. a. m.
Date 7-8 8-9 9—10 10-11 11-12 12-1 1-2 2-3 3-4 4-5 5-6 6-7
August
1975
18-19 0a 0 11 23 3 4 o o 5 1 o 0
75b 71 68 66 63 61 61 60 60 61 61 62
67C 73 75 84 93 97 98 99 100 100 99 98
19—20 0 o 4 10 10 15 11 14 5 4 2 o
79 74 71 69 67 65 64 63 63 63 63 62
64 78 85 88 92 93 95 96 96 96 96 97
20-21 0 o 6 16 11 21 22 27 12 23 11 o
73 73 72 71 71 71 71 7o 71 71 72 73
95 94 95 96 96 95 93 92 94 97 98 98
21-22 0 o o 1 2 24 22 57 31 5 o 2
87 82 76 73 71 72 72 71 70 7o 71 71
69 85 95 93 92 97 97 97 98 99 99 100
22—23 0 o o 5 12 11 26 28 14 2 1 2
77 74 73 71 71 72 72 73 73 72 72 73
85 89 9o 93 96 97 97 98 96 96 97 98
23—24 0 o 4 6 16 24 46 45 25 9 11 4
85 83 82 81 80 80 79 79 78 77 77 76
7o 76 77 77 78 78 78 79 87 93 92 92
24—25 0 o 4 8 23 34 36 18 36 18 14 o
86 84 81 80 80 79 79 78 77 76 76 75
65 71 77 81 81 79 78 80 82 84 85 90
25-26 0 o 10 11 14 27 26 4o 24 22 14 1
NR NR NR NR NR NR NR NR NR NR NR NR
74 84 89 91 93 95 97 98 99 99 97 96
26-27 0 o 13 57 47 36 20 3 6 o o o
76 69 67 66 64 63 62 62 62 61 61 61
64 81 75 77 9o 89 91 96 97 97 98 98
27-28 0 o o o 9 11 3 7 20 9 3 o
78 74 7o 67 66 65 65 64 64 65 65 66
66 78 87 92 94 95 96 97 97 97 93 90
28-29 0 o 4 1 s 13 3 15 29 7 3 o
82 79 78 77 73 71 72 71 7o 70 71 71
72 79 80 82 93 97 99 100 100 100 100 100

 

a trap catch
b temperature (°F)

c % relative humidity
NR not recorded

43

300’ Figure 27. -- Adult Male Hourly Flight Activity

250

200

ISO

50

Total Timing Trap Pherocatch, August l8-29, l975

O

 

I 1

7-8 8-9 95:0105-11 llll2l2-LI I52 213 354 4-5 5-6 617

p.m. Time (E.D.T.) a.m.

44

during the course of this 2—year study. Two were found on
apple and the other 2 were discovered feeding on the foliage
of sweet cherry. The larval parasitoid was a braconid,
Microgaster pantographae Muesebeck (Figure 39). It pupated
as the larval host reached maturity. Both the braconid
cocoon and the remaining larval head capsule were discovered
in a folded leaf. It doesn't appear that the braconid

parasitoid exerts much of a regulatory effect on g;_idaeusalis

 

populations.

G. Larval Key.

The last larval stage of §;_idaeusalis is distinguished

 

from the other 7 Michigan apple feeding tortricids in the
key on page 45. This differentiation is based on the fact

that E; idaeusalis is an external fruit feeder and leaf-fruit

 

webber, brown bodied, and has a 6-9 pronged anal comb. Some
color variation may be encountered. For example, larvae
which are feeding on succulent green growth rather than

dried foliage may appear olive in color.

45

LAST INSTAR LARVAL KEY TO LIVING MICHIGAN APPLE-FEEDING TORTRICIDS

1. Body white to pink; internal fruit feeder ------- 2

la. Body not as above; external fruit feeder
or leaf-fruit webber ------------------ 3

2. Anal comb lacking -------------- Codling Moth
Laspeyresia pomonella

 

2a. Anal comb present ------------ Lesser Appleworm
Grapholitha prunivora

 

3. Body green to yellow ------------------ 4
3a. Body brown, rarely olive ---------------- 6
4. Head capsule green --------- Red-banded Leafroller

Argyrotaenia velutinana

 

4a. Head capsule brown or black -------------- 5

5. *Female head width 1.16-1.48 mm (mean 1.33 mm); length
’ 15-21 mm (mean 17.8 mm). Male head width 1.04-1.32 mm
(mean 1.19 mm); length 13-18 mm (mean 15.3 mm)
Variegated leafroller
Platynota flavedana

 

5a. *Female head width 1.70-1.87 mm (mean 1.78 mm); length
15-24 mm (mean 20.0 mm). Male head width 1.48-1.60 mm
(mean 1.59 mm); length 16-21 mm (mean 18.3 mm) (See 5b)
Fruit-tree Leafroller
Archips argyrospilus

 

5b. *Rema1e head width 1.79-2.04 mm (mean 1.94 mm); length
20-30 mm (mean 24.0 mm). Male head width 1.54-1.87 mm
(mean 1.70 mm); length 16-23 mm (mean 20.0 mm)
Oblique-banded Leafroller
Choristoneura rosaceana

 

6. Anal comb 2-5 pronged -------- Eye-spotted Bud Moth
Spilonota ocellana

 

6a. Anal comb 6-9 pronged (Figure 31) - Tufted Apple Bud Moth
Platynota ideausalis

 

*Males distinguished from females by the presence of a pair
of internal oval organs (pregonads) located dorsally in the
fifth abdominal segment (Chapman and Lienk, 1971).

46

Conclusions and Recommendations

Pheromone trapping during 1974-1975 revealed the presence

of significant populations of §;_idaeusalis throughout south-

 

western Michigan, especially in Berrien Co. However, damage
in Michigan apple orchards caused by this insect was quite
minimal during the 2 years of this study. Thus, it does not
appear that §;_idaeusalis is an important pest at the present
time in Michigan.

Since this insect feeds and matures on a wide range of
hosts, high pheromone trap counts in an orchard cannot
necessarily be correlated with damage levels. The pheromone
may attract the insect from groundvegetation within the
orchard or possibly from hosts outside the orchard, as is
the case with red-banded leafroller. As a result, the
decision of whether to direct control measures specifically
at this insect, should be made based on damage levels observed
in the fall rather than on moth presence determined through
pheromone trapping. If damage is observed in the fall, the
following steps should be taken the next spring. Pheromone
trapping should begin early in May to determine moth presence
in an orchard vicinity. If present, a search should be made
for egg masses and larval injury throughout the season.

Since many members of the leafroller complex inflict similar

injury on apple, positive identification of §;_idaeusalis

 

injury based on damaged fruit alone is extremely difficult.

47

If mature larvae are found, one can utilize the key provided
and identify the tortricid pest species. If the pest is
identified as £;_idaeusalis, and if damage levels warrant
control, insecticides should be used. The application of

a broad spectrum organophosphate during oviposition and
hatch should provide control. It is imperative to apply
insecticides before larvae web themselves within a folded

leaf which makes them impervious to chemical control measures.

48

 

Figure 28. - Egg mass on upper
surface of apple leaf.

 

Figure 30. - Mature larva. NOte
longitudinal stripes .

 

Figure 32. - Pupa in folded apple leaf.

 

 

L,-

 

Figure 29. - Mature larva webbed
in folded apple leaf.

 

 

Figure 31. - Last abdominal segment of
mature larva showing 6-9 pronged anal
comb. the 6th prong behind 5th (arrow).

 

 

 

 

Figure 33. - Adult female.

 

 

 

Figure 34. - Foliar damage on apple
seedling. Note folded leaves
clipped at petiole.

Figure 36. - Shallow, irregular
surface feeding on apple.

 

Figure 38.: Timing trap.

49

 

 

L

 

 

Figure 35. - Clipped leaf webbed
to side of apple.

 

“Figure37.- 3MvSectar tent trap
containing adult male moths.

 

_____
......
v 6

. __ a
_‘-L_1A'A_4.:-
_ .2 ,1 --_.._~_._.-

Figure 39. - Braconid parasitoid.

59

LITERATURE CITED

Anonymous. 1959. Maps. Coop. Econ. Insect Rep. 9:35-6.

Bode, William M. 1975. The Tufted Apple Budmoth in Pennsylvania,
1974. The Pennsylvania Fruit News. 54:57-8.

Chapman, P. J. and S. E. Lienk. 1971. Tortricid Fauna of Apple
in New York. Cornell University. New York. 122 pp.

Clemens, Brackenridge. 1860. Contributions to American Lepidop-
terology.-No. 6. Proceedings of The Philadelphia Academy
of Natural Sciences. 12:348.

Fernald, C. H. 1882. A Synonymical Catalogue of the described
Tbrtricidae of North America north of Mexico. Trans. Am.
Ent. Soc. 10:23.

Forbes, W. T. M. 1923. The Lepidoptera of New York and neigh-
boring states. (Part 1). Cornell Univ. Agr. Exp. Sta.
Memoir 68. 729 pp.

Frost, S. W. 1919. The Function of the Anal Comb of Certain
Lepidopterous Larvae. J. Econ. Entomol. 12:446-7.

Frost, S. W. 1921a. Lepidoptera Injurious to the Apple in
Pennsylvania. Pa. Agric. Exp. Sta. Bull. No. 169. 16 pp.

Frost, S. W. 1921b. Late Feeding Larvae Injurious to Apple
in Pennsylvania Including Several New Injurious Species.
Jo Econ. Entomlo 143324-80

Frost, S. W. 1923. A New Apple Bud-Moth in Pennsylvania.
J. Econ. Entomol. 16:304-7.

Frost, S. W. 1942. Common Insect Larvae that Attack the Apple
in Pennsylvania. Pa. Agric. Exp. Sta. Bull. No. 420. 30 pp.

Frost, S. W. 1951. Insects That Attack the Apple in Pennsylvania.
Pa. Agric. Exp. Sta. Bull. No. 535. 30 pp.

Gage, S. H. and D. L. Haynes. 1974. Degree-day tables for several
developmental thresholds. East Lansing, Michigan; Michigan
State University (Mimeographed).

MacKay, M. R. 1962. Larvae of the NOrth American Tbrtricinae
(Lepidoptera: Tbrtricidae). Canadian Entomol. Suppl. 28. 182 pp.

51

Prentice, R. M. 1965. Forest Lepidoptera of Canada Recorded by
the Forest Insect Survey. Microlepidoptera. Canada Dept.
Forestry Publ. 1142. 4:545-834.

Robinson, Coleman T. 1869. Notes on American Tortricidae.
Trans. Am. Ent. Soc. 2:277-8.

Roelofs, W. L. and A. Comeau. 1971. Sex Attractants in Lepidoptera,
p. 91-112. In A. S. Tahori (ed.), Proc. 2nd Int. IUPAC
Cong. of Pesticide Chemistry, Tel-Aviv, Vol. 3. Gordon
and Breach Scientific Publishers, New York. 227 pp.

Ruppel, Robert F. 1974. Notes on Plotting Seasonal Appearance
of Insects (Mimeographed Handout).

HICH IES

 

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