l

i
r i

|

H

I“
J:
I
‘
.
III

[I
I!

I I

ll

7 ,7,,,
7..'I
-7 --
7 l,#..
#,;
77 i V

I“ ‘lf (1
w ‘
II I

fil

 

"IQ;
I\l—\
IUDCDLO

THE DISTRIBUHQN AND MAGNITUDE OF ENJURY
BY THE CLOVER ROOT BORER,
H‘i‘WTENUS Q33" ”MIME MAESHAM AND CLQ WEE

“fiv—w

ROOT CURCULEQ Si IONA SPF. TC) RED AND

MAMMOTH CLC’VER IN THE LOWER
PENINSGLA OF E‘CHIGAN

TIvesis (or ”19 Degree of M. 5.
MECI‘IIGA I‘I SLED: UNIVERSITY

Marry Donaié Niemczyk
1958

“A:
Jt:

 

THE DISTRIBUTION AND MAGNITUDE OF INJURY BY THE
CLOVER ROOT BORER, flylaetinus obecurue
lARSHAH, AND CLOVER ROOT CURCULIO,
Sitona app, TO RED AND MAMMOTH
CLOVER IN THE LOWER PENINSULA
OF MICHIGAN

by
HARRY DONALD NIEIICZYK

AN ABSTRACT

Submitted to the College of Science and Arts
Michigan State University of Agriculture and
Applied Science in partial fulfillment of
the requirements for the degree of

MASTER OF SCIENCE

'Department of Entomology

Year 1958

/—_:."
Approved // (\ Ck14 C]E[;~Jég:a~zl_//

ABSTRACT

During August and September of 1957 a survey was
made for the purpose of determining the distribution and
magnitude of the clover root borer (fiylastinus obscurus
Iarsham) infestation in red and mammoth clover in Michigan,
and at the same time gather similar information on the oc—
currence of clover root curculio (Sitona spp.) larval
feeding injury to these plants. A total of 1,593 roots
were dug from 8 counties in the northern half, and 38 I
counties in the southern half of the Lower Peninsula.
Eighty of these roots were from fields at least in their
first crOp year. An average of 3.4 samples consisting of
10 randomly selected roots was collected from each county
surveyed.

The results from examination of the roots collected
are outlined as follows:

1. The 1,513 roots collected from fields at least
in their first crOp year showed 33.3 percent were infested
with an average of 4.8 root borers per root.

2. Root borer infestations ranged from zero to
100 percent and varied considerably from one county to the
’next. The northernmost counties Showed a zero percent

infestation.

ii

3. Examination of the 80 roots dug from fields
less than one year old showed that none were infested
with the clover root borer.

4. Of the roots dug from fields at least in their
first cr0p year, 1,405 were examined for Sitona spp. larval
feeding injury. The results showed that 57.8 percent had
light damage, 27.7 had moderate damage, and 14.5 percent
had heavy damage.

5. Examination of the 80 roots from fields less
than one year old showed that 77.7 percent had no Sitona
spp. injury, and 12.5, 7.5, and 2.5 were respectively light,

moderate and heavily injured.

111

THE DISTRIBUTION AND MAGNITUDE OF INJURY BY THE
CLOVER ROOT BORER, fiylastinus obscurus
IARSHAM, AND CLOVER ROOT CURCULIO
Sitona spp., TO BED AND MAMMOTH
CLOVER IN THE LOWER PENINSULA
OF MICHIGAN

. by
HARRY DONALD NIEMCZYK

A THESIS

submitted to the College of Science and Arts

Michigan State University of Agriculture and

Applied Science in partial fulfillment of
the requirements for the degree of

MASTER OF SCIENCE

Department of Entomology
1958

in
4
.
u

ACKNOWLEDGEMENTS

My grateful acknowledgement is extended to Professor
Ray Hutson, head of the Entomology Department, for making
this study possible.

To Dr. Gordon Guyer, under whose direction this
study was made, goes my sincere thanks and appreciation
for his constant encouragement and enthusiastic interest.

I wish to extend my appreciation to Doctors Herman
King and Richard Kiesling for their critical reading of
the manuscript, and graduate students Jagat P. Singh, Hari

“Charan Agarwal, Arthur Wells, and Jack Eichmeier for their
able assistance on the survey trips.

my sincere appreciation and gratitude is extended
to my wife Dolores for typing the manuscript and for-her

patience and und rstanding throughout ears of study.
This «“123ch 15 henw‘d’k dad {ca chTo lm.
Deo Gratias.

iv

TABLE OF CONTENTS

Page
INTRODUCTIONOOOOOOOO...0....0.0.00.0...00.0.0.0... 1

LITERATURE REVIEW, CLOVER ROOT BORER..............
DistributionOOOOOOOO00.00.00...OOOOOOOOOO.

Plants AttaCKedOOOOOOOOOOOOOOOOOOOOOOOOOOO

QUIWW

DamageOOOOOOOOOOOOOOOOOOOOOOCO0.0.0.000...

Life History and Seasonal Activities...... 10

contrOlOOOO0.00000000000000000000000000000 19

LITERATURE REVIEW, CLOVER ROOT CURCULIO. . . . . . . . . . . 26
PROCEDURE......................................... 28
PRESENTATION AND DISCUSSION OF DATA............... 33

Clover Root Borer......................... 33

Clover root curculio...................... 41
SUMMARY........................................... 48
LITERATURE CITED.................................. 50

TABLE

II.

III.

IV.

LIST OF TABLES

Page

Occurrence of the Clover Root Borer

in.Red and Mammoth Clover Roots

Collected from Fields at Least in

Their First Crop Year..................... 34

Occurrence of the Clover Root Borer

in Red and Mammoth Clover Roots

Collected from Fields Less than One

Year OldOOOOO0.0.0000000000000000000000000 36

Percentage Distribution of Clover Root

Borer Larvae, Pupae, and Adults According

to Date Collected from Fields at Least

in Their First CrOp Year.................. 37

The Occurrence of Clover Root Curculio

(Sitona spp.) Larval Feeding Injury on

Red and Mammoth Clover Roots Collected

from Fields at Least in Their First

crop YearOOOOOOOOOOOOOOO0.0.0.00.00.00.00. 45

The Occurrence of Clover Root Curculio

(Sitona spp.) Larval Feeding Injury on

Red and Mammoth Clover Roots Collected

from Fields Less than One Year Old........ 47

vi

.Figure
1.

LIST OF FIGURES

Page

Approximate locations of sample sites
during 1957 clover root borer survey....... 29

Example of survey form used during 1957
clover root borer survey................... 31

Distribution of percent clover root borer
infestation in fields at least in their
first Crop yearOOOOOOOOOOO000.000.000.00... 38

The percent distribution of clover root

curculio (Sitona spp.) larval feeding

injury on red and mammoth clover roots

collected from fields at least in their

first crop yearOOOOOOOOOOOOOOOOOOOOO0...... 44

vii

INTRODUCTION

Each year many acres of red clover, Trifolium
partense Linnaeus, and mammoth clover, Trifolium pratense
var. pgrenne Host, are planted in Michigan. These crOps
serve as forage for domestic animals and are an important
source of income to the farmer when the seed is harvested
and sold. Michigan has maintained an average rank of fourth
among the red clover seed producing states in this country.
In 1956, 115,000 acres of red clover were harvested for seed.
This crOp was valued at over two million dollars.

,The clover root borer, Hylastinus obscurus Marsham,
has been a menace to red and mammoth clovers in Michigan
for over half a century. This insect has been blamed for
causing reductions in seed and forage yields by its burrowing
within the clover root. Upon its discovery in this state,
the root borer attracted a great deal of attention because
it threatened the clover crOp. Since then, however, little
attention has been given to this pest.

The control of the clover root borer is complicated
by the fact that the insect spends all but a few hours
of its life protected in the roots of the clover plant.
Early efforts to control this pest were largely repressive
in nature. Recommendations were made to plow under badly

infested fields immediately after the first harvest.

1

Experiments conducted during the past 15 years on insect-
icidal control of this pest have indicated that control
by this means is quite successful.

There are two insects commonly referred to as the
clover root curculios, Sitona hispidula Fabricius, and
Sitona flavescens Marsham. These two insects are not
considered serious pests on red and mammoth clover, and
their net effect upon the clover plant is uncertain.
However, the feeding scars left by the larvae do expose
the root to many pathogenic organisms, which alone or in
combination with poor growing conditions, can contribute
to the mortality of the clover plant.

The purpose of this survey was to determine the
distribution and magnitude of the clover root borer
infestation as it occurs on red and mammoth clovers
throughout the southern half and ten.northern counties in
the Lower Peninsula of Michigan and to gather similar
distributional data on the occurrence of feeding injury to
these plants caused by the larvae of the clover root

curculio.

LITERATURE REVIEW, CLOVER ROOT BORER

Distribution

Fereigg. The clover root borer, Hylastinus obscurus
Harsham, has been.known in Europe for at least a century
and a half. Information relative to the distribution of
the insect in that part of the world was best summarized
by Rockwood (1926). He stated, "According to information
compiled from various sources, the clover root borer is
now found in.Russia (Kief); Germany; Austria; France;
Czechoslovakia; England; Canary Islands; Denmark, and
Italy (Tuscany)." He further reported that the insect

occurred in Canada (southern Quebec and Ontario).

National. lost American.authors agree that the
clover root borer was introduced into this country from
Eur0pe. The means by which this was accomplished is not
known. The root borer was first reported as occurring
in the United States by Riley (1879). who indicated that
it was causing damage to red clover in.Branchport, New
York, in 1878. Rockwood (1926) indicated that in all
probability the root borer was present for many years
prior to its first discovery. Henry (1880) stated that
the root borer had taken over all the clover fields in

3

portions of Genessee county, New York. In 1888, extensive
damage to clover in Ontario, Canada, was mentioned by
Folsom (1909). By 1890, Webster (1896) found serious
infestations in the northwest part of Ohio. Davis (1894)
considered the clover root borer as one of the most
serious insect pests in Michigan at the time of his
writing. In 1909, Folsom stated that the root borer had
reached Indiana, Illinois, Pennsylvania, West Virginia,
North Carolina, and also Oregon. Using information
compiled from unpublished records. taken from the files of
the Bureau of Entomology, Rockwood (1926) found the root
borer to be present in Murry, Utah, in 1911, and also in
western Maryland in 1915 and 1916.

In the review of the literature from 1927 to 1950
the author found no reference to infestations in states
which previously had not reported the root borer's presence.
With this in mind the author surveyed the COOperative
Economic Insect Report (1952-1957). published by the
United States Department of Agriculture, in an effort to
obtain a more current distributional picture. According
to information compiled, the root borer has been reported
as a pest on clover in the following states: Michigan,
Illinois, Indiana, Ohio, Pennsylvania, Virgina, West
Virginia, New York, Washington, Oregon, and Idaho.

Michiggn. According to Davis (1894), the earliest
record of the root borer in Michigan.was 1889, in the
southern part of Monroe county. Webster (1899) ascribed
the insect's entry into this state to a continuation of the
Ohio invasion, but Davis (1894) indicated that "in all
probability specimens were brought across Lake Erie by
wind, from farther east, and lodged on the lake shore."
Davis further stated that in 1890 specimens were found
near Lansing and that by 1894 the root borer was present
throughout the southern two-thirds of the Lower Peninsula,
except for four counties in the extreme southwest corner
of the state. No mention was made of how this distribution
was ascertained.

Until completion of the present survey by the

author, there has been no further information gathered

on the distribution of the root borer in this state.
Plants Attacked

As early as 1807, various German workers came to
the conclusion that the root borer's natural food was com-
mon red clover, Trifolium pratense Linnaeus. Most authors
agreed that.mammoth clover, Trifolium pratense var. perenne
Host, is an equally susceptible host plant. Davis (1894)
indicated that mammoth clover suffered most from the root

borer.

Schmitt (1844) disagreed with other German authors
of his time in stating that the root borer occurred on
palfalfa, Medicago sativa Linnaeus. Folsom (1909) stated
that in Illinois the root borer fed on alfalfa, "but not
enough to have done any damage up to the present time."
From observations made in Ontario, Canada, Gibson (1913)
stated, "In some fields of alfalfa this borer was working
freely, causing noticable loss." Rockwood (1926) recorded
some instances of damage to alfalfa by the root borer, but
stated, that "It seems improbable that the clover root
borer will become a serious pest of alfalfa, as the rapidly
growing, tough roots of alfalfa do not appear well adapted
to the successful propagation of the species." 3

In Abergavenny, England, Chapman (1869) noted the
root borer attacking furze, Egg; europaeus Linnaeus, and
Scotch broom, Qytisus scoparius Linnaeus.

Rockwood (1926) mentioned two examples brought to
his attention of damage to garden peas by the clover root
borer. '

In 1940 Lincoln (1941) conducted studies on.host
resistance to the clover root borer and found that alsike
clover, Trifolium hybridum.Linnaeus,'was only lightly;
infested, and ladino, Trifolium repens Linnaeus, not at all.
Rockwood (1926) pointed out that alsike clover might be
severely injured in sections where recent changes from red

to alsike clover had been made.

Damage

The literature on the damage done to red clover by
the clover root borer contains some disagreement. Schmitt
(1844), while agreeing with other early German workers that
Trifolium pratense Linnaeus was the primary food of the
borer, disagreed with their theory that the insect was the
principal cause of the death of red clover in its third
year. He said that the cause of death was due to the ag-
ricultural practice of cutting clover for seed late in the
fall, which weakened the plant and exposed it to frost and
disease.

In reporting the first occurrence of the root borer
in the United States, Riley (1879) stated that, "in.Seneca,
Ontario, and Yates counties in.New York, the insect was
prevalent enough to prevent the cutting of clover, the roots
being entirely devoured and the plants pulling out with the
greatest of ease and gathering in windrows before the mower."
White (1888) reported that in Edmonton, Ontario, the borer
was doing incalculable damage to clover fields. Similar

reports were made by Davis (1894) and Webster (1899).

Folsom (1909) presented perhaps the best description
of the injury inflicted by the root borer. He stated, "An
affected plant finally wilts and dies; when pulled by hand
it breaks off at the surface of the ground. The roots of
such a plant are burrowed out longitudinally. The amount

and rapidity of injury depends not only upon the number of
insects present but also upon the amount of moisture receiv-
ed by the plant. Injured plants are liable to die late in
June or early July." There is general agreement in the
literature that clover in its first growth year with roots
being small in the spring, is not subject to attack.
Rockwood (1926) noted one unusual instance where clover of
less than one year's growth was noticeably damaged.

The publications written by Hunter (1909) and
Folsom (1909), refer to the lowering of seed yields due to
the ravages of the root borer. Practically all of these
are observational in nature, showing little or no experi-
mental evidence for such claims. ‘

Pieters and Hollowell (1924) stated that insects
rarely caused clover failure; the only insect known to be
serious was the clover root borer. They further stated
that, with but rare exceptions it damaged clover only in
the late summer of its second year. Hudson (1925) stated,
"The root borer is not regarded as an important pest
because it attacks plants in the second year of growth,
and clover, being a biennial, is usually ploughed under
after the second season." Mills (1941) pointed out that
intense injury to clover was not common and further stated
that the insect "does not usually injure stands which are
one or two years old, doing the most of its damage to

Older fields."

Pieters and Hollowell (1957) believed that one of
the principal causes of the dying out of red clover during
the second winter was the injury produced by the clover

root borer.

Newsom (1948) summarized his findings on damage to
red clover by the root borer as follows: "The amount of
injury produced may be measured quantitatively by reduction
in number of leaves produced, reduction in carbohydrate
root reserve, and differences in shoot-root ratio between
infested and uninfested plants. Infestation by the root
borer reduced the number of leaves produced 25 percent,
total sugars as much as 60 percent in heavily infested
.plants, and the shoot-root ratio about 30 percent." He
further indicated that the borer might cause outright death
of 10 percent of plants in their first crop year and might
be responsible for about 40 percent of the remaining plants
entering the winter low in carbohydrate reserves.

Elliott (1952) conducted an extensive study of the
diseases, insects, and other factors in relation to clover
failure in West Virginia. He found that a species of
Fusarium which caused root rot was generally associated
with injury by the root borer. Studies made at Pensylvania
State College (Anonymous 1948) indicated that unless the
clover root was injured, the'fungus could not enter.
lDuring July and August Fusarium spp. were found to have
entered the plant following initial injury by the root borer.

10
Life History and Seasonal Activities

Overwinterigg. In the review of literature on the
life history of the clover root borer, the author found
general agreement that there is but one generation per year
and that the adult beetles represent the primary overwintering
stage. Riley (1879) and Webster (1899) pointed out that
the insect might overwinter in all three stages. The lat-
ter author reported larvae present in clover roots at
Wooster, Ohio, on January 14, 1899. Similar observations
were made by Davis (1894). Rockwood (1926), and Lincoln
(1941). Upon examination of second crOp year fields at
Ithaca, New York, on April 13, 1947, Newsom (1948) found
that larvae comprised about 20 percent, pupae less than
1 percent, and adults about 80 percent of the total pop—
ulation.

Rockwood (1926) stated, "Adults which for any reason
have become separated from the clover roots, may pass the
winter in the soil or, rarely, under trash on the surface

of the ground."

Activity before dispersal flight. The literature
contains comparatively little detailed information on the
seasonal activity of the clover root borer. One of the
earliest and most extensive American investigations con;

cerning the bionomics of this insect was conducted by

11

Rockwood (1926), at Forest Grove, Oregon. It was found that
resumption of feeding by the adults and overwintered larvae
took place when the soil reached a temperature of about 45
degrees Fahrenheit. During March and April, the adults
worked their way to the crown of the plant where they fed
on the root tissues. Feeding activity increased as the
soil temperature reached 50 degrees Fahrenheit and, when
the air temperature at ground level was between 55 and 60
degrees Farhenheit,the borers left the roots and walked
about. This form of activity took place in March or early
April and rarely during warm days in February. Rockwood
stated that "in case of a cool, backward spring, this
movement of the beetles on foot is the only method of mig-
ration to new host plants until late in the season." 'In
studies of clover fields coming into their second crOp year,
Newsom (1948) found that the number of infested plants had
increased 52 percent prior to spring flight. This increase
was shown to have been due to movement of the beetles on
foot to these plants. '

Rockwood (1926) stated that "in.clover fields plowed
during the preceding summer and fall, soil conditions and
the disturbed, abnormal state of residues of the clover
root borer's host plant induce premature activity of the
adult borers, which attempt migration in response to the
stimulus of the first warm days of late March." This fact

was evidenced by root borers being swept from winter wheat

12

seeded on clover sod, three weeks prior to spring flight.

Based on the predominance of fertilized females in
the first flights, Rockwood (1926) indicated that a general
mating occurred previous to the first spring flights, and
that mating probably occurred in the roots, on the clover
crown, and on the ground. Schmitt (1844) observed the
beetles in capula on the clover plant during April and May
at Mainz, Germany.

Dispersal fligh . According to flight studies
made by Rockwood (1926) and Newsom (1948), dispersal of

adults by flight may take place when.the air temperature
is about 65 degrees Fahrenheit. Their findings showed that
little flight occurred until the air temperature reached
70 degrees Fahrenheit; however, the latter author observed
.that once flight had begun the beetles might fly at lower
temperatures. Both workers agreed that the time of first
spring flight was governed primarily by soil temperature
and consequently would vary from year to year. At Ithaca,
New York, Newsom (1948) observed first flight in late April
of 1942; however, in 1947 flight did not begin until the
latter part of May, because of an unusually cool and late
spring.

First flights have been recorded by Rockwood (1926)
at Forest Grove, Oregon, on.April 7, 1916. Davis (1894)
:reported capture of the first beetle in flight on.Hay 3.

13

1893, presumably near Lansing, Michigan. Late first flights
have been recorded by Rockwood (1926) at Forest Grove,
Oregon, on.May 8, 1917, April 26, 1920, and May 5, 1917,

at Wapato, washington.

Rockwood (1926) found 85 to 90 percent of the
borers in first flight were females and that 90 percent of
these were fertilized before flight. Additional studies
indicated that the root borer might fly as high as 50 feet
and travel a distance of two miles.

Flight studies on the comparative number of borers
flying in fields in the first cr0p year fields and those
in the second crOp year fields were made by Newsom (1948).
Using sevensby-nine inch board traps with upper and lower
surfaces coated with "Tree Tanglefoot" and placed fifteen
inches above the plants, Newsom.showed that over four times
as many beetles at one location and over twice as many at
another flew into each square foot of second cr0p year
field as in first crOp year fields. According to Newsom,
these data indicated that the beetles made numerous short

flights in second crop year fields.

Oviposition. Webster (1910) found that upon reach-
ing a suitable clover plant the female root borer gouged
out a small cavity or burrow in the clover plant, sometimes
in.the sides of the root two or three inches below the crown.

Into the sides of the burrow she deposited, singly, about

14

six small, white elliptical eggs. According to Rockwood
(1926), the female burrowed to a depth of 6mm. before
beginning to oviposit. The egg galleries varied in char-
acter from.simple grooves starting at the crown, to those
consisting of spiral grooves almost girdling smaller roots.
The construction of egg galleries required nearly a month.
Males and females were common in the egg galleries during
the whole reproductive period, and it was believed that
females mated more than once during their reproductive
period.‘ Toward the end of May these egg galleries were
abandoned by the adults, which then probably died outside
the plant. Rockwood was first to observe that the female
root borer might oviposit in as many as four clover plants
in one season.

Davis (1894), who studied the life history and dis-
tribution of the clover root borer in.Michigan, made the
following statements regarding oviposition: "As soon as
warmer weather comes in spring, the beetles revive and
begin burrowing and feeding. This year, by the 20th of
May, the females had commenced depositing eggs along the
galleries made in boring....They (the eggs) are not left
in the gallery with the beetle, but are pushed into the
dead-part of the stem at one side, securely packed and
covered from view with refuse from the burrow." These
statements seem to indicate that oviposition took place

before dispersal flight; however, in the description of

15

the root borer's life history, no mention was made of a
spring flight.

Webster (1910) stated that in Ohio oviposition oc-
curred between the middle of May and June 20. Hudson (1925)
reported that during breeding studies carried on in Ontario,
Canada, egg laying continued throughout the summer. The
beetles started to lay during the latter part of May and
continued up to August 3. Rockwood (1926) stated that the
number of eggs were at maximum toward the end of May. In
studies made in New York during 1940, Lincoln (1941) ob-
served that eggs were most abundant from middle June until
the middle of August. .

Schmitt (1844) stated that the female root borer
laid four to six eggs. Riley (1879), Webster (1899) (1910)
and others agreed with Schmitt and seemed to indicate that
these were all the eggs the female laid in one season.
Hudson (1925) found that the largest number of eggs secured
from a single female was sixteen. Rockwood (1926) stated
that the total number of eggs laid by a single female sel-
dom exceeded twenty. In laboratory studies on oviposition,
Newsom (1948) found that females laid an average of thirty-

three eggs in one season and fifty-eight during two seasons.

Incubation. From observations made near Mainz,
Germany, Schmitt (1844) stated that eight days were re-

quired for first larvae to appear. The writings of early

16

American workers such as Riley (1879) and Webster (1896,
1899, 1905, 1910) indicate that they accepted the incubation
period of eight days as given by Schmitt. Hudson (1925)
found from a close study of thirtysfour eggs, that the max-
imum length of the egg stage was seventeen.days; the min-
imum nine days; the average, 12.67 days. Using as incuba-
tion chambers salve boxes containing moistened plaster of
.Paris cells, Rockwood (1926) concluded that at effective
temperatures the incubation period varied from 32 days in
May to 16 days in June. Under a controlled laboratory
temperature of 65 degrees Fahrenheit, Newsom (1948) found~
that the incubation period required about two weeks.

Larvae. Rockwood (1926) described the newly hatch-
ed larvae as "helpless, inactive creatures" which apparent-
ly found the leverage made possible by the small egg cells
"absolutely necessary for the successful attack of clover
roots." While conducting studies of the larvae, Newsom
(1948) transferred newly hatched larvae to freshly out root
sections by lifting a small flap of bark and placing there-
in a single larva. The larva soon died but, when five or
six larvae were introduced at the same time, survival was
high.

I Rockwood (1926) stated that at first the larvae
made small tunnels at right angles to the egg gallery, but

as the larvae increased in size the burrow generally conformed

17

to the longitudinal axis of the root.

Webster (1910) described the larva as being an
eighth of an inch long, dingy white, with a honey-yellow
head and brown jaws.

The literature contains relatively little infor-
mation based on experimental evidence relative to the du-
ration of the larval period. After extensive studies,
Rockwood demonstrated that the larval period varied from
32 to 65 days and that at least 50 days were required under
natural conditions. Newsom (1948) found it varied from 40
to 77 days when studed at a controlled temperature of 65
degrees Fahrenheit.

Papas. In New York, according to Riley (1879),
pupal formation took place at the end of the larval mine
and pupae could be found as early as September. However,
Newsom (1948) found that pupae usually appeared in August
and were most abundant during September in.the same state.
At Fair Grove, Oregon, Rockwood (1926).determined the pupal
period as 10 days, from August 17 to August 27, 1917, and
12 to 13 days during September and early October. He also
reported that Webster and Mally had recorded pupal periods
of 7 to 11 days at Wooster, Ohio, during July 1896. In
the summary of his work, Rockwood stated that the pupal
period lasted from 8 to 13 days.

Webster (1910) described the pupa as smaller than

18

the larva, dingy white, and with two minute spines on t0p
of the head and two larger spinous projections at the anal
extremity. The description given by Rockwood (1926) general-

ly agreed with the above but was much more detailed.

Adults. According to Rockwood (1926), newly trans-
formed adults were pale, creamy white and seven days elapsed
before there was sufficient sclerotization to allow feeding.
In the summary of his extensive studies, Rockwood stated
that the develOpmental period from egg to adult covered
not less than 60 days but might be 90 or more. Thus the
total life span of an individual root borer might be a year
or more. Corroborative evidence for Rockwood's findings
was gathered by Newsom (1948). He found that development
from egg to adult required about three months. In the
spring of 1946 Newsom collected 92 pairs of adults for
oviposition studies. Under the conditions of a screened
insectary,-a total of 31 adults were still alive in April
1947 and on October 26, 1947, one pair of the beetles was
still alive.

Folsom (1909) described the adult beetle as follows:
"The beetle is small.... at most only 2.5 mm. in length...
dark brown or blackish, cylindrical, hard-bodied and hairy.
The elytra, or wing-covers, often have a reddish tinge,
and are coarsely punctate; the head and pronotum are more

finely punctate, the latter bearing sparse long hairs.

19

The tibia have large teeth near the outer end."

During the course of Newsom's (1948) studies, he
found it necessary to separate adult male beetles from_
females. No reliable characters were known for disting-
udshing living males and females. Newsom was the first
to discover a method for such differentiation. If the
female was held by forceps, on her side, in the struggle
to escape the sixth and seventh tergites were extruded,
eXposing the secondary sexual characters. When a male
beetle was held the same way only the seventh tergite was
exposed but this is much larger and more heavily sclerotized
than in the female. In addition, the aedeagus of the male,
a heavily sclerotized tubular structure, is not found in

the female.
Control

Natural Enemies. The literature indicates that
the clover root borer has very few natural enemies. Riley
(1879) found the larva of a soldier beetle, (Telephorus)
Cantharis bilineatus Say, preying on the clover root borer.
Rockwood (1926) reported that H. L. Parker reared larvae
of the soldier beetle, Chauliognathus pennsylvanicus DeGeer,
on the larvae of the clover root borer. During his investi-
gations concerning the life history of the clover root

borer in Canada, Hudson (1925) stated that he found no

20

parasites or predacious enemies of the root borer.

Rockwood (1926) observed the entomogenous fungus,
(Spgrotrichum) Beauveria globulifera (Spegazzini) Picard,
attacking clover roOt borer adults. He indicated that
infection of adults probably took place during their move-
ment from.plant to plant. However, occasionally larvae
and pupae were attacked within the clover root. This path-
ogen.was most prevalent in the fall and spring on low, wet,
poorly drained land.

During April and May 1920, Rockwood (1926) attempted
to find bird enemies of the clover root borer. Twenty-two
species of birds were collected during the height of the
root borer's dispersal flight. Examination of stomach
.contents indicated that eight species of birds had eaten
a total of thirty-nine root borers. The cliff swallow,
Petrochelidon lunifrons Say, had consumed twenty-seven of

the thirty-nine insects found.

Resistance. Very few investigations have been con-
ducted on the resistance of red clover to root borer at-
tack. Preliminary results from studies on.host resistance
conducted by Lincoln (1941) showed a variation in infesta-
tion of the different red clovers ranging from 13 to 50
percent, the variation being entirely due to root size.
Further investigations by Lincoln‘gt_§l. (1942) showed

that the variation in infestation due to root size, found

21

during the 1941 investigations, completely disappeared and
all strains of red clover were infested.

During experiments on chemical control of the clover
root borer on twenty different varieties of red clover,
Gyrisco and Marshall (1950) observed little or no difference
in.root borer infestation among the varieties in the check

plots.

Cultural. Early efforts to control the clover root
borer were largely repressive in nature., Experiments
conducted by Webster (1899) at Wooster, Ohio, showed that
plowing down badly infested clover fields immediately after
removal of the first hay crop (July 8) resulted in.killing
nearly all borers present in the roots. Examination.of
decayed roots in the plowed fields, three months later,
showed a total of four live adult borers. Similar examina-
tion of decayed roots in neighboring unplowed fields showed
that larvae, pupae and adults were present. Webster (1910)
further stated that if plowing was delayed for a few weeks
the larvae would have transformed into pupae, which require
no food, and then plowing would have little or no effect
on the borers.

Hudson (1925) stated, "The control of this insect
is simple. Ploughing under clover after the second crOp
is taken off, and the destruction of volunteer clover is

all that is necessary."

22

After considerable experimentation and observation,
Rockwood (1926) made the following conclusions regarding
cultural control of the clover root borer: (1) Plowing and
harrowing clover fields soon after the seed crop was re-
moved resulted in.killing many of the borers; (2) The
practice of green.manuring and late fall and winter plow—
ing had little or no effect on the root borers; (3) Early
spring plowing of heavily infested fields was completely
ineffective as‘a control measure; (4) Serious injury to
red clover might be avoided by cooperative community farm
practices, such as not allowing clover to stand undisturbed

for two or more years.

Chemical. Davis (1894) used large quantities of
nitrate of soda, murite of potash, and kainit as possible
repellents for the clover root borer. He found that these
applications had no effect on root borer infestation, and
in fact, caused serious injury to the clover.

Application of phosphatic fertilizers to clover
fields in order to induce more rapid growth was tried by
Rockwood (1926). The results of these experiments indicat-
ed that no definite conclusions could be drawn regarding
any difference in root borer infestation among plots tested.

Early experiments on chemical control of the clover
root borer were conducted in New York by Lincoln gt_§l.

(1942) during the 1941 growing season. Paradichlorobenzene

23

at 1,000 pounds per acre showed repellent and fumigant
action, reducing the number of roots infested and also the
number of root borers developing within the roots. Naphthav
lene at 2,000 pounds per acre was effective as a repellent
but not as a fumigant. Dichloroethylether, applied as a
fumigant after the clover roots became infected, showed
some promise.

Schwardt‘gt_§l. (1947) applied one percent DDT dust
and one percent benzene hexachloride to an even stand of
red clover and timothy, in its first crOp year. The results
showed that neither material gave significant control of
the clover root borer. Tests conducted by Newsom (1948)
during 1946 and 1947 indicated that 5 percent dusts of
benzene hexachloride and chlordane showed great promise for
clover root borer control.

During the period 1946 to 1948, Marshall gt_gl.
(1949) conducted tests to determine the comparative ef-
ficiency of benzene hexachloride, chlordane, parathion,
and DDT in control of the clover root borer, when applied
as dusts or sprays to red clover in its first crop year.
Insecticide applications were made before the spring dis-
persal flight. Benzene hexachloride, as a dust at 1.5
pounds of actual gamma isomer per acre, showed no phyto-
toxicity and gave excellent control. Parathion, chlordane,
and DDT also gave good control, but results were not as

consistant as those obtained with benzene hexachloride.

24

When used as sprays at the rate of one pound actual tox-
icant per acre, all materials gave unsatisfactory control.

In 1949 Gyrisco and Marshall (1950) tested the
materials mentioned by Marshall §t_§l. (1949) as well as
toxaphene, methoxychlor, aldrin and dieldrin for control
of the clover root borer. All materials were applied as
dusts. Aldrin and dieldrin applied at two pounds of actual
toxicant per acre and benzene hexachloride at one pound of
gamma isomer per acre were most effective, followed by
chlordane, parathion, toxaphene and methoxychlor, respec-’
tively. App and Everly (1950) also reported that benzene
hexachloride at 1.25 pounds gamma isomer and aldrin at 2.0
pounds actual toxicant per acre, gave good control as sur-
face applications.

From 1950 to 1954 Gyrisco gt_gl. (1954) used aldrin,
dieldrin, heptachlor, isodrin, endrin, chlordane, toxaphene,
methoxychlor, TDE, parathion, NPD (Tetra—n-propyl-
dithionoperphosphate), lindane and benzene hexachloride
in eleven different tests for control of the clover root
borer in New York. Test results indicated that a pound of
actual toxicant of aldrin, dieldrin, and heptachlor dusts
gave consistantly good control. Dust applications of
lindane, isodrin, chlordane, and benzene hexachloride at
one pound actual toxicant per acre gave good control, but
parathion, endrin, toxaphene, TDE, and NPD at one pound

and higher dosages gave unsatisfactory control.

25

Preliminary tests with aldrin and dieldrin indicated that
spray applications were less reliable than dusts.

Experiments were conducted at Wooster, Ohio, by
Weaver and Haynes (1955) to test the effectiveness of band-
placed insecticides for clover root borer control. Band
placement of aldrin and benzene hexachloride at 0.75 pound
toxicant per acre gave good control. Further tests by
Weaver §t_§l. (1957) showed that aldrin, lindane, and
heptachlor, at the concentration mentioned above, gave an
average of 83.9 percent control.

Of ten insecticides tested by App (1956) for control
of the meadow spittlebug and clover root borer, heptachlor
and aldrin dusts at 1.5 to 1.75 pounds actual toxicant per
acre reduced clover root borer populations 97 to 100 per-
cent, respectively, the former being applied in the spring;
the latter, in the fall. "Fall applications of benzene
hexachloride at 1.0 and 1.25 pounds gamma isomer per acre
reduced clover root borer populations 37 and 72 percent,
respectively, and spring applications of 0.75 to 2.0 pounds
from 13 percent to 89 percent."

Woodside and Turner (1956) reported effective
control of the clover root borer with applications of
benzene hexachloride at one pound gamma isomer per acre in
granular, spray, and dust formulations. Tests with dieldrin,
aldrin, isodrin, endrin, and heptachlor, at one pound actual

toxicant per acre, and chlordane at 5 pounds gave good control.

LITERATURE REVIEW, CLOVER ROOT CURCULIO

There are several species of insects belonging to
the family Curculionidae that are often referred to as the
clover root curculios. The literature on these insects
indicates that Sitona hispidula Fabricius, is the most com-
mon species, and the one usually associated with injury to
red and mammoth clover. However, Elliott (1952) found
that the majority of clover root curculios collected in
west Virginia were identified as Sitona flavescens Marsham.

The adult clover root curculio feeds at the edges
of the leaves chewing out characteristic crescent-shaped
patches. Bigger (1930), and others have agreed that this
injury has relatively little effect on the clover plant.
The most damage is caused by the larvae, which first feed
on the nodules and small fibrous roots, later attacking
the large roots. Sizeable cavities and grooves are excavated
along the tap root, the latter sometimes encircling the
entire root. Examination of a heavily infected field by
Bigger (1930) in Illinois on.May 18, 1927, showed from 36
to 41 larvae per square foot. Jewet (1934) examined a two
year old clover field in.Kentucky in September 1932 and
found 71 percent of the clover roots showed curculio injury.
Studies by Elliott (1952) in West Virginia indicated that
injury caused by the clover root curculio facilitated entry

of root rot organisms. Most authors agreed that this
26

27

insect feeds on all common clovers, alfalfa, soybeans, cow-
peas and other legumes.

According to Metcalf §t_§l. (1951), most of the
insects pass the winter as young larvae. In the spring -
these larvae develop by feeding on the crown and roots
of the clover plant. During May and June the adult beetles
emerge. These beetles feed for about six weeks on the
leaves of the clover plant. After a summer period of less-

er activity the adults again become active in early fall.
During this time maturation takes place and the females
deposit their eggs about the crowns of the plants. Most
of the eggs hatch in the fall, but some hatch the following
spring. A considerable number of the adults survive the

winter.

PROCEDURE

The survey area included all counties south of a
line extending from Whitehall, in.Nuskegon county, to the
tip of Huron county, and the following counties north of
this line: Mecosta, Osceola, Missaukee, Kalkaska, Antrim,
Otsego, Montmorency, Oscoda, Ogemaw. The approximate
location of each sample site is shown in Figure 1. In
each of the counties south of the line mentioned above,
an average of 3.8 samples, consisting of ten clover roots
each was collected. The number of samples collected from
a given county depended upon the availability of sample
sites, amount of clover grown, and the size of the county.
In the survey area north of the above mentioned line an
average of 1.9 samples per county was collected. Except
fbr one sample collected in.Wayne county on March 29, 1958,
the survey covered the period from.August 8, 1957 thru
October 4, 1957.

Of the 159 samples collected during the survey,
151 were from clover fields which were at least in their

1

first crap year , and 8 from fields less than one year old.

Fields of either red clover Trifolium pratense Linnaeus,

 

1The term "first crap year" as used in this paper
refers to the first calendar year following the year which
a clover field was seeded.

28

  

44le ..s UPERIOR

r".,
IPT1:
.

ONTONAGON I": 1 .
L- . 1...... .3
GOGLBOC -1_. 1 _1_ __1 8 _____3 1
_ , 1MARQU£TTE , 1 _1 1 we: 1
\1 IRON I____._] 1 ALGER 15—6“°°Lcm1-—.—.__L.l
smut FEST? ; Mam-e11

I
109 1 "" .’ —1 MONT mm
\ ANTRJM orsaco ImoRmcv1-

\ .

um .—- -—-—}°—-—+—

my? GRAND IKfUMSKA1CRAwr0R01 OSCOOA1"ALCONA
1 +— —"—- —- ~-—..\—. ._ _._
MANISTEEIWEXFORD;MUN-1E1WOMMON1OGEMAW1 IOSCO

 

.I_..

_l
‘7 —1_J —1—L_1_ 1711mm
M"‘50'41 LAKE osc:0LA1 CLARE icLADwnj'...

:
Q

\ .1

t -—v——~- .7; - 1w .
U

\

2

o
HURON
o

    
    
 
   
 
 

' MECOSTA - - . ._.. _._-
. OCEANA Remoo 115mm: MIDLMDL .1.
O

'—L
._.._11 ._.-_.l__.. ——f' SANILAC
o . o . 'MONTCXLM [E—RATIOTI SAGINAW-L1 70519-1. 0
my??? .1 1: .1; '41-‘51: -1.. '

1 6011:8th I LAPEER |

 

 

 

 

1 x: m: ~ °
OTTAWA' 1 1011M 1cu~70~1summz

'0
i ._...L. J:.._.I._j. .._!._1_ . I._J._.‘[-: o
‘1

ALLEGAN TBARRY 1 urpu 1INGHAM1UVINGSTONI OAKLAND "9°“.

0 o 1 ° 0 0
.._._r. 7. i’;_1_._._l_._.'
VANBURf-"1KALAMA2001 CALHOUN 1 JACKSON IWASHTLNAW1 wAvn:
. ' o o o . 0 . ' o I .—l..
° .1'.—'—.r°‘.1—T-"— Tl . ‘

o ' ‘
1 CASS is 495""1BMNC" 1HILLSDAL£1 LENAWEE [MONROE

t
- 1%
1“

 

Approximate locations of sample sites during

Figure 1.
1957 clover root borer survey.

29

30

or mammoth clover Trifolium pratense var. perenne Host,
were indiscriminately selected for sampling. Samples were
taken by walking approximately 100 yards into each field
and digging a randomly selected clover plant every 10 yards.
Both living and dead clover plants were accepted as sample
plants. In order to assure removal of the entire root a
tile shovel with a blade 16 inches long was used to remove
plants from the ground. The teps of the clover plants

were removed about 3 inches above the crown and the roots
placed in poultry size polyethylene plastic bags. A rubber
band was placed about the Open end of each plastic bag in
order to prevent the roots from drying out. The location
of the sample site and observational notes on the general
condition of the field was recorded on a specially prepared
survey form (Figure 2). Upon completion of a survey trip,
the plastic bags containing the clover roots were placed

in a cooler at 39 degrees Fahrenheit until dissection took
place.

In the laboratory, examination and dissection of
the roots was completed without the use of magnification,
since larvae, pupae, and adults were large enough to be
seen with the naked eye. The diameter of each root was
measured at the crown and recorded on the survey form.

Each root was examined for Sitona spp. larval feeding
scars. This was recorded as none, light, moderate, or

heavy. Each root was then carefully dissected over a

Figure 2. Example of survey form used during 1957 clover
root borer survey.

RED CLOVER ROOT SURVEY - 1957

SAMPLE NO. ‘ H. Niemczyk
DATE TAKEN - Dept. of Ent.
COUNT! M.S.U.
TOWNSHIP

TIME
WEATHER
TAKEN BY

 

 

 

 

,Sec.

 

 

 

REMARKS

 

 

 

 

 

 

PLAN Sitona BORER NO. BORERS DIAM. OF

 

-TOTAL NO. BORERSooeooooooooooooo
$PLANTS INFESTmooooooooooooooe
NO. BORERS PER PLANT-00.00.0000.
% PLANTS WITH Sitona DAMAGE.....
AVG. DEGREE OF Sitona DAMAGE...._______
AVG. DI“. OF ROOTSooooooooooooo__'___

31

32

white porcelain pan 19 inches long and 13 inches wide, and
the number of clover root borer larvae, pupae, and adults
present was recorded. The porcelain pan was emptied before
dissection of another root began in order to avoid recount-
ing root borers already counted. Whenever possible, roots
were examined and dissected as soon as they were brought
from the field, but because of the large number of clover
roots collected during the survey, laboratory work was not

completed until November 1, 1957.

PRESENTATION AND DISCUSSION OF DATA
Clover Root Borer

A total of 1,593 clover roots were examined during
the survey. Of these, 1,513 were from clover fields at
least in their first crop year, and 80 were from fields
less than one year old. The results from examination of
these roots are shown in Table I and Table II respectively.

Of the 1,513 roots collected from.fields at least
in their first crap year, 33.3 percent (504 roots) were
infested with an average of 4.8 clover root borers per
plant. The percent of root borer infestation.among the
rsites from.which these roots were collected ranged from
zero to 100 percent. Table III shows the percentage dis-
tribution of larvae, pupae, and adults according to the
date collected. The distribution of the average percent
of root borer infestation among the counties from.which
the 1,513 roots were collected is shown in Figure 3.

The results of examination.of all clover roots
collected during this survey showed that the clover root
borer was present in each county south of a line extending
from.Whitehall, in Muskegon county to the tip of Huron
county, and also in the following counties north of this
line:Mecosta, Osceola, Missaukee, Ogemaw (Figure 3).

33

TABLE I

34

OCCURRENCE OF THE CLOVER ROOT BORER IN RED AND MAMMOTH
CLOVER ROOTS COLLECTED FROM FIELDS AT LEAST
IN THEIR FIRST CROP YEAR.

 

 

Number

Percent Average
of Roots of Roots Number of

Percent

 

 

County Examined Infested Borers

Per Root Larvae Pupae Adults
Alcona 10 O 0.0 0.0 0.0 0.0
Allegan 40 35 1.0 22.5 12.5 65.0
Antrim 10 0 0.0 0.0 0.0 0.0
Barry 40 40 2.0 29.1 25.3 45.6
Berrien 3O 43 2.0 44.3 32.7 22.9
Branch 40 45 2.3 44.4 21.1 34.4
Calhoun 4O 30 1.8 28.5 11.0 60.3
Cass 40 30 1.9 38.7 40.0 21.3
Clinton 40 73 4.3 27.2 26.6 46.2
Eaton 49 49 2.1 23.1 22.1 54.8
Genesee 39 13 0.7 46.1 23.1 30.8
Gratiot 49 35 1. 6 45.1 26 .8 28.1
Hillsdale 30 67 3.4 39.8 22.3 37.9
Huron 3O 27 8.3 13.8 31.0 55.2
Ingham 50 41 1.7 71.8 15.4 12.8
Ionia 4O 38 1.5 31.7 30.0 38.3
Jackson 30 57 2.5 9.2 5.3 85.5
Kalamazoo 29 27 0.9 11.1 11.1 77.8
Kalkaska 20 O 0.0 0.0 0.0 0.0
Kent 40 58 3.6 48.9 29.4 21.7
Lapeer 4O 13 0.7 48.1 33.3 18.5
Lenawee 40 75 4.2 30.8. 18.9 50.3
Livingston 4O 30 1.8 31.0 23.9 45.1
Macomb 30 23 0.7 57.1 14.3 28.6

35

TABLE I (Continued)

 

 

 

 

Number Percent Average
County of Roots of Roots Number of Percent
Examined Infested Borers

Per Root Larvae Pupae Adults
lecosta 40 25 0.5 21.0 21.0 57.9
Missaukee 30 10 0.3 77.8 22.2 0.0
Monroe 30 50 3.0 21.1 24.4 54.4
Montcalm 40 28 1.1 36.4 29.5 34.1
Montmorency 10 0 0.0 0.0 0.0 0.0
Muskegon 30 30 1.2 45.7 0.0 54.3
Newago 2O 60 3.5 58.0 10.0 31.9
Oakland 40 8 0.1 25.0 25.0 50.0
Ogemaw 10 10 0.5 80.0 20.0 0.0
Osceola 3O 13 1.1 75.0 21.9 3.1
Oscoda 10 O 0.0 0.0 0.0 0.0
Otsego 10 O 0.0 0.0 0.0 0.0
Ottawa 30 30 1.8 41.8 41.8 16.4
Saginaw 40 5 0.3 60.0 20.0 20.0
Sanilac 60 48 2.3 35.8 23.3 40.8
Shiawassee 40 25 1.2 30.4 39.1 30.4
St. Clair 49 14 0.4 53.8 0.0 46.2
St. Joseph 29 31 2.3 36.2 15.9 42.8
Tuscola 50 38 1.7 24.1 12.6 63.2
Van.Buren. 40 30 1.4 16.4 16.4 67.3
Washtenaw 19 62 2.7 55.6 13.0 31.5
wayne 10 30 0.3 33.3 0.0 66.7

“

 

36

TABLE II

OCCURRENCE OF THE CLOVH-"t ROOT BORER IN RED AND MAMMOTH
CLOVER ROOTS COLLECTED FROM FIELDS
LESS THAN ONE YEAR OLD.

 

 

Number Percent Average

 

 

County of Roots of Roots Number Percent
Examined Infested Borers
Per Root Larvae Pupae Adults

Huron 10 0.0 0 0.0 0.0 0.0
Ingham 10 0.0 0 0.0 0.0 0.0
Kalamazoo 10 0.0 0 0.0 0.0 0.0
Muskegon 10 0.0 0 0.0 0.0 0.0
Newago 10 0.0 0 0.0 0.0 0.0
Oakland 10 0.0 0 0.0 0.0 0.0
St. Joseph 10 0.0 O 0.0 0.0 0.0
Washtenaw 10 0.0 0 0.0 0.0 0.0

 

 

37

TABLE III

PERCENTAGE DISTRIBUTION OF CLOVER ROOT BORER LARVAE, PUPAE,
AND ADULTS ACCORDING TO DATA COLLECTED FROM FIELDS
AT LEAST IN THEIR FIRST CROP YEAR.

 

 

Number Number of
Date Collected of

Roots' Larvae Pupae Adults Larvae Pupae Adults

Average Percent of

 

 

1957

August 8, 3O 0 0 0 0.0 0.0 0.0
August 9. 3O 6 . 9 7 50.0 28.9 21.9
August 15, 60 119 55 51 52.9 24.4 22.7
August 16, 100 123 73 56 48.8 28.9 22.2
August 17, 80 53 21 13 60.9 24.1 14.9
August 28, 4O 47 46 80 27.2 26.6 46.2
September 4, 120 108 91 107 35.3 29.7 34.9
September 5, 80 63 30 69 38.9 18.5 42.6
September 10, 7O 46 32 26 44.2 30.8 25.0
September 11, 80 26 6 20 50.0 11.5 38.5
September 12, 120 60 42 86 31.9 22.3 45.7
September 13. 7O 27 15 44 31.2 17.4 51.2
September 17, 4O 20 25 30 26.7 33.3 40.0
September 18, 110 47 42 208 15.8 14.1 70.0
September 23, 180 36 33 188 14.0 12.8 73.2
October 4, 60 38 10 11 64.4 16.9 18.6
1958

March 28, 1O 1 O 2 33.3 0.0 66.6

 

 

  

, Gm (A KE 5 UPERIOR

L. f .
ONTONAGON -
,3

H- .
‘L._ I'd ! BARAGA

. ‘1 I
Cdcwc _L_ ___-_,
. t . __i - -
. -o---I— I MARQUETTE ‘ 8 J ! we: I
-\.\I 1RON I_,_._I i ALGER [SIC-1100mm}. _____'I_I
I'oncxmsou' r'j [IL-r:- 1 I ”rem-f-Iu
’//T©-6

1::
J
\l . 9 .
1413111141118!9 ( 1 I
( CQ_11\ARLLVOIX‘.\. "ET.
7 /.1§\ .\ Icmmi -
1 l \ .—--I ~ masoucm
I [EELANAU \~ I __IJ_.__, _,
1 Q A L" - ’ MONT
10 mm I7115mm Imomcv- mm
\' um .9..._.!._o.._.:_. _I.. _.

13111121;r GRAND l'W‘ASKAICRAmeoi OSCODAI ALCONA

_IIRAV£RSF:I_O_ i ”I 0. —'>— o—

mmsmesxroao 'muxttiaoscomoquchAwII IOSCO

10 10L
..._-._ ‘I‘J‘r‘LT it...

MASON LAKE oscmLA! CLARE icLADm

3
£1 .

5 -—-I—.—.L3 % - I... ’ ."Jl‘fi-
\

2

CHIPPEWA

 

 
 
   
 
 
   
   

 

 

' MtcosrA" -
. own name 2 I ISABELLA MIDLAmI—u-L

 

 

304° "W m. '51,. "1:4“
118—- 435. L5.

KENT
OEOAWAI I 1011111 [CLINTON I 1111111111551:

"4 1

5: L53438__l73|2513‘
‘( W7

‘1

 

 

 

l cautsuL 3!

ALLEGAN Imam Inna" [1111mm luvmcsmul WW” .

A9, LILAFLALFBO' _._I_§ _.

1V‘"°”RF"IKM.42Muooj CALHOUN 1 JACKSON IWASHTENAWI mm:
1.2. + 2_'L I_JQT. 4.62 '.3.0
I CASS i5 JOSEPH] BMW“ ImusoALzI LENAWEE Iuonaos

55"!“ __L_29_i_..3l-j—h-§--i 67 '_ _7.5._L '50

Distribution of percent clover root borer
infestation in fields at least in their

first crap year.

Figure 3.

38

39

In the northern survey area it was found that infestations
became smaller the farther north the survey area extended.
The northernmost counties surveyed showed no infestation.
The resons for this phenomenon were not investigated.

In the southern survey area considerable vari-
ation was evident in the average percent of clover root
borer infestation (Figure 3). These percentages ranged
from a low of 5 percent in Saginaw county to a high of 75
' percent in.Lenawee county. Rockwood (1926) indicated that
temperature (soil and air), moisture, condition of the host
plant, and topography are largely responsible for the dis-
tribution of the clover root borers and the damage done by
them. Although these factors were not a part of the present
study, the author feels that it is reasonable to assume
that they were partially responsible for the variations
in root borer infestations found.

During the course of the survey it became obvious
that the acreage of red and mammoth clover grown varied
considerably throughout the state. It was felt that this
fact also might be partially responsible for the variations
in root borer infestation.found. assuming that the acres
of red clover harvested for seed in 1954. as given in the
1954 Census of Agriculture, was indicative of the amount
grown in a given county in 1957, a comparison of this inp
formation and the percent of root borer infestation in the

.counties surveyed was made. It was found that Antrim county

4o

harvested 1,007 acres and showed a zero percent infestation,
Ionroe county harvested 967 acres and showed a 50 percent
infestation, Lonia county harvested 7,521 acres (the highest
in.the state) had an infestation of 58 percent and Lenawee
county harvesting 5.605 acres had a 75 percent infestation.
0n the basis of this information it was therefore concluded
that little or no relationship existed between the amount

of clover grown in a county and the percent of root borer
infestation. .

As indicated by Rockwood (1926), Newsom (1948), and
other workers, clover in its first growth year is seldom
attacked by the clover root borer, primarily because the
roots are small in.the spring. Evidence derived from exam,
ination of 80 clover roots collected from fields less than
one year old lends support to this information, As shown
in Table II, none of the roots examined contained clover
root borers. These roots averaged 5.26 mm. in diameter at
the crown.

The average percent of larvae, pupae, and adults,
when.considered with respect to the date collected (Table
III). showed considerable variation. The most outstanding
variation was that from.roots collected on.0ctober 4. 1957.
These roots contained an average of 64.4 percent larvae,
16.9 percent pupae and 18.6 percent adults. One of the
roots collected in Osceola county contained 20 root borer

larvae. By way of comparison, Newsom (1948) examined first

41

crap year fields on October 6, 1946 and found 55 percent
larvae, 7 percent pupae and 58 percent adults. Similar
findings were reported by Folsom.(1909) and Rockwood (1926).
It must however be emphasized that the findings of the above
workers were based on the examination.of relatively few
fields in.a comparatively small area. Therefore, variations
in.percent of the different stages at a given time, (as
demonstrated in this study) would be less likely to appear.
variations in.environmental factors such as temperature,
soil type, moisture, tapography, and condition of host plant
can not be naturally encountered unless an extensive area

is studied. The author therefore feels that a plausible
explanation for the variations in percent.of larvae, pupae
and adults shown.in Table III, is the variation in the ens
vironmental conditions encountered during this survey.
However, before any definite conclusions can be drawn,

further study will be necessary.
Clover Root Curculio

Until completion.of the present survey by the author
there was no information.available relative to the occur-
rence of clover root curculio feeding injury on red and many
moth clover in.Nichigan. This study was made in conjunction
with the survey of the clover root borer. Before the clover

roots were examined for clover root borer content, they

42

were first examined for Sitona spp. feeding injury. In
order for the injury to be specifically attributed to the
Sitgna spp. it would have been.neeessary to collect the
roots at a time when.the larvae were actually in the pro-
cess of feeding on the root. This however, was impossible
because of the time of year that the survey was conducted.
The description of the Sitona spp. larvae feeding soars as
given by Bigger (1950), Jewet (1934), Metcalf gt_al. (1951)
and Dickason and Every (1955) were used as criteria for
injury identification. No attention was given.to the par—
ticular species inflicting the injury.

The injury to Clover roots was classified as none,
light, moderate and heavy. Hone meant that the roots were
free of any feeding scars; light, from one to approximately
10 feeding scars; heavy, the roots were badly gpuged and
scarred: moderate was approximated as that between 10
feeding scars and heavy injury. Roots which were broken
or damaged, such that the feeding scars were unidentifiable,
were not counted as part of the roots examined.

A total of 1,485 roots were examined. Of these
1,405 were from fields at least in their first crap year,
and 80 from fields less than one year old. Of the 1,405
roots examined, 72 percent (1,012 roots) showed varying
signs of clover root curculio injury. Of these 1,012
roots, 57.8 percent showed light damage, 27.7 percent

moderate damage and 14.5 percent were heavily damaged.

43

Table IV shows a complete breakdown of the percent of damage
found on clover roots collected from fields at least in

' their first crap year, according to the county from which
the roots were collected. The location of the individual
sample sites is the same as that shown on Figure 1. Figure
4 shows the occurrence of clover root curculio injury vary-
ing from light to heavy as determined by the survey. An
examination of Figure 4 and Table IV readily shows that
injury to red and mammoth clover by the clover root curculio
is very common in.lichigan.

The literature examined by the author contained no
information relative to the question of whether or not the
clover root curculio damages the roots of clover less than
one year old. In order to determine whether such damage
occurs, 80 roots from fields less than one year old were
examined. The results of these examinations is shown in
Table V. These data show that although feeding injury is
less severe than.that in older fields, it nevertheless

does occur on.young plants.

  

14 K5 .5 UPERIOR

aucumN
ONTONAGON I
g.__| I , BARAGA [3 .
“9“” 1 ° -—L—-—I 8 . " ‘I I
.\ “-. o IMARQUETTE. , I 1 Lucr- I
- N . .
\-\I 'R -__.._.._I r1 ALGER I-SEIOJOLCRAFTI__ "—41 CHIPPEWA .
, I "" ‘— . L_,._._._.
IDICNINSSL 1‘ j DELTA -I I MACKINAC ”Lj
. .I Ll /"~
I I "/0 9“-
momma 9 ‘ ‘. I
( {131211va “ET.
2 /‘ QB.\ .\ _Icm
. \ -— museums:
I, LEéLANAU \I I__ I-—--j--- .._ _
I_.--
' MONT ALP
\0 ANTRIM -OTS£GO IMORENCYI w

\° um .29 |1_0_0_I _. _I. _—

J GRAND IWSMICRAerRDI OSCODAI ALCONA
17RAV_ER$EI_9§_I_ _. I__63_ I_.O_

MANISIEEIWEKFORO WUKEEIROSCOHMONIOGLMAW W: ”355°
urn—it . - _L- J “L
—I I I: ARENAC

W50” LAKE IOSCEOLAI CLARE IGLADWI

5.
3’ I
5 — I_..—I 12 I w ' “gum“
\ ._-
2

BENZ

   
    
  
   
 
   
  

 

 

ocLANA "m IMECOSYAIusAasuA MIDLANDL ‘ - I
WW’i h2I_ .. ‘L .
T‘I— TUSCOLA IW'UC

1:531“; 50113'6fi—I I ”ONTCALM MFMTINI SAGINAW-‘II77 1" ’L 80
“:71 Law.— r 1S1"-

 

aLLL

. LAPEER
'U MIAMI KENT Ih3 10N1A —ICL1NTONIsulAWAss&I ems“ Ill—333811!
x 62.9 .1 £114 s,_i_,3 83
‘ ALLECAN I BARRY I EATON IINGHAMILIVINGSTONI “MN” I m?”
N

.._'17.T _1 82L 5TJ_5_7_I_Z ' .I_.75_
_IVANBURf-"IKAUMAZOO—I- CALHOUN I JACKSON IWASHTENAWI my»:
86I_7_11.I_I£3_ I_§3_r .L_T-_|I_. .I_EZI—L '.8.8

ass I5 JOSEPHI BRANC" INILLSOALEI LENAWEE IMONROE

.BEMEIéQ -'L.7.i-1'_.5_.t lOOI. 91 '6

Figure 4. The percent distribution of clover root curculio

(Sitona spp.) larval feeding injury on red and
mammoth clover roots collected from fields at

least in their first crop year.

44

45

TABLE IV

THE OCCURRENCE OF CLOVER.ROOT CURCULIO (Sitona spp.) LARVAL
FEEDING-INJURY ON RED AND MAMMOTH CLOVER
ROOTS COLLECTED EROM FIELDS AT LEAST
IN THEIR FIRST CROP YEAR.

 

 

 

 

Number Percent Feeding Injury
County of Roots
Examined None Light Moderate Heavy

Alcona 10 100.0 0.0 0.0 0.0
Allegan 39 23.1 59.0 12.8 5.1
Antrim: 10 80.0 0.0 20.0 0.0
Barry 38 18.4 39.5 28.9 13.2
Berrien 29 13.8 37.9 34.5 13.8
Branch 35 14.3 40.0 8.6 37.1
Calhoun 29 17.2 31.0 24.2 27.6
Cass 40 40.0 45.0 10.0 5.0
Clinton 39 46.2 48.7 5.1 0.0
Eaton 46 32.6 39.1 13.1 15.2
Genesee ' 29 24.1 58.6 13.8 3.5
Gratiot 44 36.4 25.0 20.5 18.1
Hillsdale 28 0.0 35.7 42.9 21.4
Huron 39 35.9 30.8 20.5 12.8
Ingham 58 19.0 56.9 20.7 3.4
Ionia 31 38.7 41.9 12.9 6.5
Jackson 24 29.2 54.2 12.5 4.1
Kalamazoo 35 57.1 20.0 22.9 0.0
Kalkaska 20 5.0 65.0 15.0 15.0
Kent 34 5.9 61.8 17.7 14.7
Lapeer 32 12.4 31.3 31.3 25.0
Lenawee 33 3.0 42.4 39.4 15.2
Livingston 38 23.7 42.1 26.3 7.9
Macomb 26 15.4 42.3 23.1 19.2

 

45

TABLE IV (Continued)

 

 

 

 

Number Percent Feeding Injury
County of Roots ‘
Examined None Light Moderate Heavy
Meoosta 37 51.4 24.3 24.3 0.0
Hissaukee 28 35.7 57.1 7.2 0.0
Monroe 20 35.0 35.0 20.0 10.0
.Montcalm 28 57.1 28.6 14.3 0.0
Montmorenoy 10 40.0 0.0 60.0- 0.0
Muekegon 38 44.7 47.4 5.3 2.6
Newago 22 63.6 22.7 9.1 4.6
Oakland 44 25.0 29.5 29.5 15.9
Ogemaw 10 50.0 40.0 0.0 10.0
Osceola 29 27.6 51.8 10.3 10.3
Oacoda 8 37.5 50.0 0.0 12.5
Otsego 10 0.0 0.0 100.0 0.0
Ottawa 29 31.0 51.7 13.8 3.5
Saginaw 32 9.4 53.1 31.3 6.2
Sanilac 51 19.6 31.4 25.5 23.5
Shiawassee 35 17.1 45.7 22.9 14.3
St. Clair 40 15.0 50.0 22.5 12.5
St. Joseph 36 25.0 52.8 16.7 5.5
Tuscola 39 23.1 43.6 20.5 12.8
.Van Buren 38 26.3 63.2 10.5 0.0
washtenaw 27 40.8 29.6 14.8 14.8
wayne 8 12.5 75.0 12.5 0.0

 

 

¢,_~—.

47

TABLE V

THE OCCURRENCE OF CLOVER ROOT CURCULIO (Sitona spp.) LARVAL
FEEDING INJURY ON RED AND MAMMOTH CLOVER
ROOTS COLLECTED FROM FIELDS LESS
THAN ONE YEER OLD.

 

 

 

 

Number Percent Feeding Injury
County of Roots 4

Examined None Light Moderate Heavy
Huron 10 100.0 0.0 0.0 0.0
Ingham 10 70.0 20.0 0.0 10.0
Kalamazoo 10 60.0 10.0 30.0 0.0
Muskegon 10 60.0 10.0 20.0 10.0
Newago 10 100.0 0.0 0.0 0.0
Oakland 10 70.0 20.0 10.0 0.0
St. Joseph 10 60.0 40.0 0.0 0.0
Washtenaw 10 100.0 0.0 0.0 0.0

 

 

SUMMARY

The primary purpose of this study was to determine
the distribution and magnitude of the clover root borer
(gylastinus obscurus Marsham) infestation in red and mammoth
clover in.Michigan, and at the same time gather similar
information on the clover root curculio (Sitona spp.)
injury to these plants. A total of 1,593 roots were dug
from.fields in 46 counties. Eighty of these roots were
from.fields less than one year old and 1,513 were from
fields at least in their first crop year. An average of
3.4 samples consisting of 10 randomly selected roots was
collected from each county surveyed.

The results from.examination of the roots collected
are outlined as follows:

1. The 1,513 roots collected from fields at least
in their first crop year showed 33.3 percent were infested
with an average of 4.8 root borers per root.

2. Root borer infestations ranged from zero to
100 percent and varied considerably from one county to the
next. The northernmost counties showed a zero percent
infestation.

3. Examination of the 80 roots dug from.fields
less than one year old showed that none were infested with
the clover root borer.

48

49

4. Of the roots dug from.fields at least in their
first crop year, 1,405 were examined fer Sitona spp. larval
feeding injury. The results showed that 57.8 percent had
light damage, 27.7 had moderate damage, and 14.5 percent
had heavy injury.

5. Examination of the 80 roots from fields less
than one year old showed that 77.7 percent had no injury,
and 12.5, 7.5, and 2.5 were respectively light, moderate
and heavily injured.

LITERATURE CITED

Anonymous
1948. Clover injured by borer killed by disease.
2nn. Eept. Penn. Agr. Expt. Sta. (1947)
1: 1 0

App, B. A.
1956. Control of the clover root borer and the
'- meadow spittlebug on red clover. Jour. Econ.
Ent. 49: 161-1640

App, B. A. and R. T. Everly
1950. Insecticide dusts to control the clover root
borer and the meadow spittlebug. U. S. Dept.
Agr., Bur. Ent. Pl. Quar., Mimeo. E-811.

Bigger, J. H.
1930. Notes on the life history of the clover root
curculio, Sitona hispidulg Fab., in central
IllinOiSO Jouro Econ. Ent. 23: 334-3410

Chapman, F.
1869. Notes on the habits of Phlonphthorus

rhododactylus and gylastes obscurus. Ent.
“on. “as. 3 6-80

 

DaV18, G. C. . ‘
1894. Insect of the clover field. Part I. Insects
destructive to clover. Much. Agr. Expt. Sta.
Bul. 116: 41-47.

Dickason, E. A. and R. W. Every
1955. Legwme insects of Oregon. Oregon State
College Ext. Bul. 749: 14-15.

Elliott, E. S. -
1952. Diseases, insects, and other factors in
relation to red clover failure in West Virginia.
W. va. Agr. Expt. Sta. Bul. 351T: 1-65.

Folsom, J. W.

1909. The insects pests of clover and alfalfa.
Univ. Ill. Agra EXPtO Sta. Bul. 134: 113-1970

50

51

Gibson, A. -
1913. Clover root borer. Ann. Rept. Ent. Soc.
Ontario (1912) 43: 13.

Gyrisco, G. G. and D. S. Marshall
1950. Further investigations on the control of the
clover root borer in New York. Jour. Econ.
Ent. 43: 82-86.

Gyrisco, G. G., A. A. Huka, L. Hapkins and H. H. Neunzig
1954. Insecticide concentrations and timing of
applications for control of the clover root
borer. Jour. Econ. Ent. 47: 327-331.

Henry, W. A.
1880. The clover root borer. Amer. Entomol.
3: 227.

Hudson, H. F.
1925. Notes on the life history of the clover root

borer, Hylastinus obscurus. Ann. Rept. Ent.
Soc. Ontar o 45 53: 92-93.
Hunter, B.

1909. Clover-seed production in the Willamette
valley, Oregon. U. S. Dept. Agr., Bur. Pl.

Jewet, H. H.
1934. The clover root curculio. Ky. Agr. Expt.
Sta. CirCQ 42: 13-230

Lincoln, C. G.
1941. Studies on the biology and control of the
clover root borer lastinus obscurus.
Ann. Rept. CornellEUfii?TEK§F. Eifit. Sta.
(1940) 54: 129-130.

Lincoln, C. G., L. D. Newsom and H. H. Schwardt
1942. Studies on the biology and control of the
clover root borer, Hylastinus obscurus.
Ann. Rept. Cornell Univ. Agr. Eipt. Sta.
(1941) 55: 127-128.

Marshall, D. S., L. D. Newsom, G. G. Gyrisco and H. H. Schwardt
1949. Control of the clover root borer. Jour.
Econ. Ent. 42: 315-318.

Metcalf, C. L., W. P. Flint and R. L. Hetcalf
1951. Destructive and useful insects. HcGraw Hill
Book Company, New York. 1071 pp.

”'l

52

Mills, H. B.
1941. Montana insect pests 1939 and 1940. Twenty-
Eighth Report of the State Entomologist.
Mont. Agr. Expt. Sta. Bul. 384: 12;

Newsom, L. D.
1948. The biology and economic importance of the
clover root borer, gylastinus obscurus Marsham.
Thesis for degree 0 . ., orneII Univ.
129 pp. Unpublished.

Pieters, A. J. and E. A. Hollowell
1924. Clover failure. U. S. Dept. Agr. Farmers
Bul. 1936: 1-24.

 

1937. Glover improvement. U. S. Dept. Agr.
Year Book 1937: 1190-1214.

Riley, C. V.
1879. The clover root borer. Rept. U. S. Comm.
Agr. 1878: 248-2500 .

Rockwood, L. P.
1926. The clover root borer. U. S. Dept. Agr.
Bul. 1426: 1-280

Schmitt P.
1844. Entwicklungsgeschichte des Hylasinus trifolii
(muller)o Stettino Ent. Ztgo : Eg- c

 

Schwardt, H. H., L. D. Newsom and L. B. Norton
1947. Increasing red clover yields by treatment
with DDT or hexachlorocyclohexane. Jour.
Econ. Ent. 40: 363-3650

Weaver, C. R. and J. L. Haynes
1955. Band placement of insecticides for clover
root borer control. Jour. Econ. Ent.
48: 190-1910

Weaver, 0. R., K. P. Pruess and J. L. Parsons
1957. Further tests of band placement of insecticides
for clover root borer control. Jour. Econ.
Ent. 50: 255-2560

Webster, F. M.
1896. The clover root borer. Ohio Agr. Expt. Sta.
Bul. 68: 31-330

 

 

1899. The clover root borer.
Bul. 112: 143-1490

 

1905. 7THe clover root borer.
Bur. Ent., Circ. 67: 1

 

1910. The clover root borer.
Bur. Ent., Ciro. 119:

White, J.
1888. The clover root borer,
(Muller). Canad. Ent.

Woodside, A. M. and E. C. Turner

53
Ohio Agr. Expt. Sta.

U. S. Dept. Agr.,

-5,

U. S. Dept. Agr.,
1-50

§%lastes trifolii
2:10

1956. Control of the clover root borer in Virginia.
Jour. Econ. Ent. 49: 640-643.

w. W. v

Circulation :npué‘

.4

3; uh! 59;

JAN-B—Hgsm-— pqfl / MS;

 

 

 

 

I
9916

1 93 03168

 

I
I
II
l
l
I
l
I
II
III
l
I
ll.
I4
I!
I
ll.
I'll
II
II
l
'1'
II
II
III
I
4
ll!
lll'l
1'!"
[I
l