The Insect pest survey bulletin

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Title:
The Insect pest survey bulletin
Physical Description:
v. : maps ; 26 cm.
Language:
English
Creator:
United States -- Bureau of Entomology
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
Bureau of Entomology, U.S. Dept. of Agriculture
Place of Publication:
Washington, D.C.
Publication Date:
Frequency:
monthly, mar-nov. plus annual[1926-]
monthly, apr.-nov.[ former 1922-1925]
monthly, may-nov.[ former 1921]

Subjects

Subjects / Keywords:
Insect pests -- Periodicals   ( lcsh )
Entomology -- Periodicals   ( lcsh )
Genre:
serial   ( sobekcm )
federal government publication   ( marcgt )

Notes

Dates or Sequential Designation:
Vol. 1, no. 1 (May 1, 1921)-
Numbering Peculiarities:
Vol. 14, no.9 issued only as a supplement..
Issuing Body:
Vols. for May 1, 1921-1934, issued by the U.S. Bureau of Entomology; 1935- by the U.S. Bureau of Entomology and Plant Quarantine.
General Note:
"A monthly review of entomological conditions throughout the United States" (varies slightly).
General Note:
Includes annual summary starting in 1926.
General Note:
Includes some supplements.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030368280
oclc - 08816534
lccn - sn 86033699
Classification:
lcc - QL1 .I56
System ID:
AA00023228:00143

Full Text







THE INSECT PEST SURVEY

BULLETIN


Volume 18 Supplement to Number 4 June 15, 1933


BUREAU OF

ENTOMOLOGY AND PLANT QUARANTINE

UNITED STATES

DEPARTMENT OF AGRICULTURE

AND

THE STATE ENTOMOLOGICAL

AGENCIES COOPERATING


LIBRARY
,TATE PLANT BOARD




I







INSECT T PEST SURVEY BULLETIN


Vol. ig Supplement to Number 4 June 15, 193g



POPULATION AND HOST PREFERENCES OF JUNE BEETLES

IN SOUTHERN WISCONSIN IN 1935, 1936,AND 1937

By T. R. Chamberlin, C. L. Fluke, Lee Seaton, J. A. Callenbach,

and P. 0. Ritcher-/


The following is an account of the distribution, flight, habits, and
host preferences of species of Phyl l pha'a in southern Wisconsin,-2/based on
studies made in 1935, 1936, and 1937. Figure 1 shows the localities in which
these studies were conducted. In some of the localities more than one grove
was observed.

Studies in 1935

The year 1935 was a year of the flight of the major brood, generally
known as "brood A." The first beetle was recorded at Madison on April 26,
before work was begun by the Bureau of Entomology and Plant Quarantine. Fair.
ly heavy flights had occurred at Gays Mills by May 12. The spring season was
late and the flight prolonged, and heavy flights occurred infrequently on warm
nights. Between May 7 and August 7, 49 flights were observed in 14 districts.
An area was selected in each district which showed, on general examination,
moderate-to-heavy feeding and the presence of a variety of herbs, shrubs, and
trees. Groves, largely of bur oaks, showing intense beetle feeding, were
avoided because of the scarcity of alternative hosts. Each area was observed
from one to many times, as determined by its availability and its value as a
collecting ground. Most of the observations were made between 7:30 and ll:30
p.m. Airand soil temperatures were usually recorded at the beginning of the
observation period, at the beginning and end of the flights, and at frequent
intervals during the observation period.


l'This project is a part of the June beetle investigation being conducted co-
operatively 0oy the Division of Cereal and Forage Insect Investigations of the
Bureau of Entomology and Plant Quarantine, U. S. Department of Agriculture, and
the Wisconsin Agricultural Experiment Station through its department of economic
entomology. Ritcher made the flight observations at Gays Mills, Wis., in 1935
and Callenbach those in 1936 and 1937. Chamberlin, Fluke, and Seaton made the
observations in the other districts for all 3 years.

2/One locality included, Sturgeon Bay, is not in southern Wisconsin.


- 225 -








S226 -


The heaviest flights of beetles occurred late in May and early in June
and, on occasions during this period, beetles concentrated on some kinds, of
trees, as bur oak, willow, and hickory, in such numbers that samples could be
taken by shaking the branches over canvas. A few of these samples were used
in attempts to estimate the proportions of various species present in the
locality, but the accuracy of these estimates depended on the accuracy of an
assumption (based on general observations) that most of the beetle population
of the particular area was concentrated on these hosts. In most cases this
assumption probably was correct, but at times temperatures and wind so affect-
ed the movements of the beetles as to cause them to be widely scattered over
a variety of plants and in such numbers that, had they gone to these trees,
they would have altered the proportions of the species actually found there.
It seems difficult, therefore, to estimate the relative numbers of species
present in a given area from the numbers found on any single host. Where many
kinds of host plants are considered there are further complications, as nearly
all the beetles can be collected from low-growing plants, whereas a relatively
small proportion of the beetles on the taller types is accessible.

The relative tenderness of the leaves appears to influence tho selec-
tion of hosts by various species of beetles. Bur oak seemed to be the pre-..
ferred host of PVltophaga hirticula (Knoch) early in the season but later,
when the oak leaves had become tough, hickory was preferred. For a consider-..
able period toward the end of the season P. tristis (F.) was not found in the
field, and it was concluded that this species had ceased emerging; but at Ripon,
Wis., on July 10, large numbers were taken from tender second-growth leaves of
bur oaks that had been stripped previously by beetles.

In certain areas beetles fed on species of plants that were not fed
upon to any extent in other areas, and this feeding was not dependent on the
presence or absence of other hosts. For example, thero was in general practi-
cally no feeding on boxelder, yet at Gays Mills this host was fed upon, even
though other hosts were abundant in the immediate vicinity. Air currents in-
fluence the movements of beetles to or from hosts, therefore some beetles may
go into the ground in different fields on different mornings and return to
different hosts or different sides of the same host on different nights.
These habits made it difficult to take any samples closely comparable with
others, even in the same area. Temperatures seemed to determine the extent
to which beetles fed on low shrubs or trees. On cool nights the beetles did
not fly to any extent but issued from the ground and climbed and fed on the
nearby shrubs. These observations show that care should be used in attaching
much significance to counts made on various plants, no matter how accurate
these may be, unless the counting be continued over a long period of time and
under a groat variety of conditions.


























































Figure l.-Map of Wisconsin showing localities in which
flight studies and collections were made.







- 227 -


In addition to shaking the limbs of preferred host trees and shrubs
over canvas, from two to five collectors picked beetles by hand from all
kinds of hosts on which they were found. Attempts were made early in June
to devote a definite amount of time to each species of host, but variation
in population wns found to induce either such dispersion or such concentra-
tion of the beetles on their various hosts that the amount of time spent in
this way gave a poor idea of host preferences or total populations. After
July 1, when beetles became considerably reduced in numbers, an area was
entered, its host plants were listed, and all beetles observed within reach
were removed from each host. Several persons often collected from different
species of hosts simultaneously and often from the same species of host so
that the total number of beetles taken should average into figures upon which
a fair estimate of the relative abundance of the species of beetles upon
certain species of hosts could be based. This method seems to give c definite
indication of the relative importance of each species of host in each area as
a source of food for the beetles, and for this re:sqon these counts seem partic-
ularly valuable.

At present the authors know of no method of estimating accurately the
population of the various species of Phyllophta, based solely on counts of
the feeding adults; however, larval counts and counts of adults in the soil
made before emergence, in the same areas in which flights are observed, should
increase the accuracy of estimates. These additional counts should also be
valuable in improving estimates of host preferences.
Flight.--Small flights of beetles occurred when air temperatures were
as low as F0P. One fair-sized flight began at this low temperature near
Blue Mounds, Wis., on June 22, 1935, but the soil temperature on this occasion
was 60.g. Air temperatures above 60 are favorable for fairly large flights,
and these increased at temperatures of 65,or above. Mating by species other
than Phyllophaga tristis was heaviest at 67 to 71. When, later in the
season, higher temperatures occurred, beetles were not so abundant and it
could not be determined whether these higher temperatures were more favorable
to flight than the lower ones. In May and June many nights were too cold for
flight and there were heavy rains which in some cases depressed the tempera-
tures and intefered with flight. Light showers interfered very little with
flight, provided the temperatures were high enough. After the first of July
temperatures were high enough to permit flight almost every night, but by this
time most of the beetles had died.

Population.--A total of 12,053 beetles were taken by hand picking and
in a few cases by shaking of branches from determined hosts as given in table
1, which also shows the percentage of the total represented by each species
in the collections before July 1, after July 1. and for the entire season.
The most abundant species at all times were Phyllophaga rugosa (Melsh.),
P. hirticula Knoch, and P. fusca (Froel.), in the order named. T. tristis
was fourth in abundance before July 1 but fifth after July 1, and for the whole
season was replaced by P. implicita (Horn). These five species mnaLe up 98.13
percent of the total number of beetles taken before July 1, 97.90 percent of
" the total taken after July 1. and 98.09 percent of the total taken during the
whole season.









22g -

Table 1...-Comparative abundance of various species of

Phyllophaga. brood A, 1935


Species


SBefore
SJuly 1

:Percent
*


P. rugosa (Melsh.)----------: 41.26
*


hirticula (Knoch)--------

fusca (Froel.)--------.

tristis (F.)------------

implicita (Horn)--------

balia (Say)-------------

ilicis (Knoch)----------

futilis (Lec.)---------

nit ida (Lec.)--------

anxia (Lec.)------------

drakei (Kby.)-----------

spreta (Horn)-----------

prunina (Leo.)----------

marginalis (Lec.)-------

crenulata (Froel.)------


33.75

18.72

2.4o

2.00

.67

.44

.26

.15

.12

.10

.07

.03

.03

.02


Total beetles----------- lo0,673
*


After


: 1,380


After
July 1

Percent

50.65

24.34

10.50

4.44

7.97

.00

.22

.00

.50

.00

1.09

.00

.00

.22

.07


For
Season

Percent
p
42.34

32.66

17.78

2.63

2.6g
.60

.41
: 1.78






.23

.19



: .22

,o6

S .02

.05

.02
120053









- 229 -


Host preferences..In the 14 districts in which host preferences of
the beetles were studied, a great variety of host plants occurred, but the
number of species of hosts varied considerably in the different districts.
For example, only bur oak, aspen, hickory, elm, and sumac occurred in the
grove at Madison, whereas at Waunakee these and 16 other species of hosts
were present, The districts were as follows: Dane, Waunakee, Madison,
Blue Mounds,11*and Verona, in Dane County; EdgertonI in Rock County;4/
Blanchardville, in Lafayette County; Sturgeon Bay, in Door County; Ripon,
in Fond du Lac County;Merrimack in Sauk County; Mineral Point, Linden, ard
Hollandale, in Iowa County; and Gays Mills, in Crawford County.

Tables have been made classifying each species according to the host
from which it was taken in each collection, but these are too voluminous to
be included hero. A total of 49 collections from the 14 districts have been
consolidated and shown in tables 2 and 3. Table 2 gives all the beetles
collected before July 1 and their hosts, and table 3 gives the sane for
beetles taken after July 1.

It will be noted that there are three entries in most of the spaces
in these tables, consisting (reading from the top) of a percentage, a number,
and a percentage. The top percentage represents the proportion of the species
given at the top of the column which was taken from the host at the left; the
number represents the individuals of that species taken from that host; and
the lower percentage, the proportion of all individuals of all species found
on that host represented by the species at the head of the column. For example,
we find in table 2 that 646 individuals of Phyllophaga rugosa were taken from
hickory, and that this represented 14.7 percent of the total number of P.rugosa
taken and 63.5 percent of the total individuals of all species taken from
hickory. Percentages are not shown in cases where they are very low.

Phyllophaga rugosa was taken in all the districts where flight studies
were made and, as shown in tablq 1, it was the most numerous of all species
and comprised 42.34 percent of the total beetles taken. It was also the most
general feeder and was taken from 35 hosts. It fed heavily on hickory, bur
oak, willow, poplar, elm, basswood, and, in the Gays Mills area, on cultivated
cherry and boxelder. The first six of the hosts furnished 57.g percent of the
total taken before July 1 and 80.2 percent of the total taken after July 1.
None were taken from basswood after July 1.


31The grove studied was south of Blue Mounds, near the boundary between Dane
and Iowa Counties.

/The grove was north of Edgerton, in Dane County.






-. 230 -


Phyllophaga hirticula was also taken in all the localities given, but
was very scarce at Gays Mills and not abundant at Madison. Considering the
whole of southern Wisconsin, it was next in abundance to P. ruosa and corn-.
prised 32.66 percent of the total taken.. Although P. hirticula was taken
from 22 species of hosts, it does not appear to be so general a feeder as P.
rugosa. It fed predominantly on bur oak, hickory, and hazel, those hosts
furnishing 85.1 percent of the total taken before July 1 and 74.1 percent of
those taken after July 1. It may be noted in the table that hickory furnished
3.9 percent of those taken before July 1 and 51.8 percent.of those taken after
that date, whereas bur oak furnished 73.8 percent of those taken before July
1 and 3 percent after that date. As stated before, this change in feeding
habits seemed to occur while bur oak leaves were becoming tough.

Phyllophaga fusca was also taken in all districts studied. Taking
southern Wisconsin as a whole, it was the third species in abundance. It
is a rather general feeder and was taken from 25 species of hosts. It fed
predominantly on cultivated cherry, bur oak, hickory, hazel, dogwood, poplar,
and willow, those hosts furnishing 87.3 percent of the total taken before
July 1 and 92.4 percent of the total after that date. It may be noted in com-
paring tables 2 and 3 that none was taken from cultivated cherry after July 1
and that while only 9,3 percent of the total were taken from dogwood before
July 1, 63.4 percent were taken from that host after that'" date.

Phyllophaga tristis was taken from all districts studied except at
Dane and Merrimack. It is, however, known to occur in both places. Consider-
ing southern Wisconsin as a whole, it was the fifth species in abundance. It
feeds primarily on oak, especially bur oak. Before the first of July 91.8
percent of the total number were taken from bur oak and 3.9 percent from other
oaks. After July 1, 82 percent were taken from bur oak and 18 percent from
red oaks.

Phyllo]phaga implicita was fourth in abundance in southern Wisconsin.
It was primarily a 'illow and poplar feeder, but was taken from four other
hosts. Before the first of July 86.9 percent of the total were taken from
willow and 2.8 percent from poplar. After July 1, 93.6 percent were taken from
poplar and 6.4 percent from willow.

Other species.-.The remaining 10 species, which together approximated
2 percent of the total, were taken from relatively few hosts. These can be
found in tables 2 and 3. Dogwood was the favorite host of Phyllophaa drake
both before and after July 1, and dogwood and hazel were preferred by Pnitida,
Most of the P. anxia weie taken from willow. The seven specimens of P. spreta
were taken -from cultivated cherry at Gays Mills.

Any summary such as the foregoing, which gives the total percentages of
various beetles collected from different hosts over an entire season, may con-
ceal some of the host preferences because of the variation in population of
certain species in different localities. Thu, it is possible to collect more
specimens of a given species of beetles from an unfavored host, where this
species is abundant, than from a favored host where the-species is scarce.
Much may be gained, therefore, from a careful study of each collection made in
each district. It should be emphasized that this was done,, and that the
estimates of the host preferences and the prevalence of various species based
on the individual collections are essentially in agreement with those based on
the condensations given in tables 2 and 3.











Table 2.- Beetles of PbylloDpaa casut before July 1. 1935


0 a .. . 4 U
w I4 I I I .4 4 4 u.
4.1
Host 0 P. 04 A. __
1U.7 3.9 10.9% .*% 15.3% 2.1%
646 141 218 1 11 1 1pl8
Hickor_ 61. i13.% 21.4 - 1.1 A. I- --
n.5% 73.0 n.s 91-% Ti.4 3.6 9.1% 33.3%
505 2655 235 235 1 1 1 1 3f4
Bur oak 13. 73.0 6.9 6.% ,onS ,04 .03f 1.*3i
.K % 2 .7% 1.41
40 7 1.2 7 1 67
Red oak 59.7 41 10.4 17. -lO.q 10- 1. I
.y .3? % ~o.
34 2 6 2 3 447
White oak 72.3 2k 12.7A h 64
1.% .9 5 2 3. 9.1% 66.7%
85 34 9 1 5 1 2 137
iS oak 6 24. 6. .7 .7____ _____
-~--TJ ~^ -y ^-^T5^3 ^ ^
fEQZiWep. 249 107 246 I 6 1 I 2 1 618
inc. Aspen 40,o3 17.3 39.% .616 .97% .6 .1 .31 .1-- ,.- -
1.7 .5% 9.3% 2. 54.56 62.
74 19 .85 2 6 o 296
Dogwood 25.(A 61.44 62.65% .7___ _ __ i 2.0< 1.4 -- ^ -- --- -
13.9 .7f .7% .4 6.9% 1.4 T3. 9. 1%'
611 24 94 1 185 1 1 1. 6 924
Willow 66.1A 2. 64.6 1 4A 2.01 9 1t :1 *1 .60,-
2.5% 7.4 9.55o ~r .6 IS. 7 72..7, "
110 268 52 1 7 15 8 3. z 6
Hazel .2-3.7 _-1 9W.64 .A i .24 l. r 3.2 A .74 .-,64 -- -. -- --- -
.... 6.26 1. 7.0% .3% 6.2-
273 1 32 1 6 1 328
Elm __g__ 8 .g A .116 q.8C __ S161 1.8 ___ __ .3% ___ 1- -- -
3.7% 2o.9% 2.1% 7.7%
165 1 57 1 1 1 226
]hjtternut 2.2- _--- --- W w _-_
31 49 1 1 1 133
Bitternat 60. 36. .3 .- *. ...8
+ 2.f -.- 333% -
30 i106 i is 1 149
_-_-._. _I_ '*1 ,; ,; ?.___T5._ ----
_ "- --- -'T
3 t 3 5% 33 .3*
12 814 1 1 1 99
pberry 12.1% 84.8 % 1.0_ 1.04 1.0% -- -
1 1
Gooseberry i100. -- -- - - - -

2 2
--2 1 - - -- -
Cultivated 118 2 1121
Ape......97.5i 1.7% 7----- --
0
Su n.,flower
_ .a 3.
262 3 2 1 268
Basswood -7.8 1. .7 4. 00.
Cultivated 776 T13 6 17 6 1.4% 14.~ [7 .%;3
cbry 0 ~2 71 ,46__6% .1% ___ -















Table 2 (Cont'd).-Beetles of Pbyllophaga caught before July 1, 1935


.4 G < U* .1 2 5 S



1 1 2


37 37

78 5 6 1 90
4-^





1 1

d ater 100.0% .___ _____ __________


1.7%
1 37 35


Ash 12. 97.83
7lmof 13 6 2 2190
191



Ba 10of 10 62 21
011*9 6l1. 94 28.64 ___ __ .rA _ __ __ __ __ __ __ _

41 10 10 4 65
irolwooa 6.11 _s.W 1. .1 6.___
2.3% 2.f 3.5% -4% 6%-14.9%
103 96 69 1 7 280
Plu 61. .2
42 3 2 1 4 52
Thoru sple 8 0.8-. 3.S .1.i 7.7 .____-

6 6
Rlttereweet 100.0% _____ _________________ _______ ______ __________ ______

1 1
Blackberry 100.0%_________ _____________

3 3

1 1
Serviceber- _______ 1 00.

1 1
Strwberry _____00.0 _____ ______ ____

1 1
lderberry 100.0_ _
1 1
-n_____-_loo __ _
14.3%
Black-eyed 3 4 7
S_,42t. OA i5.7..10%
1 1 2
.4%
2 1 3
Wild zeurry 66.7W 1 mil__
6.2%
1 1
Wild crr-nt_ 100,0% __ __

Total 4,4o4 3,600 1,998 256 213 72 47 28 11 16 2 3 13 7 3 10o,67









Table 3.--- Beetles of phyllophaga caugit after July 1, 1935


p. P. P. p.
P. hirtic- P. P. Implic- P. P. P. m&rgi- crenu-
Host rutosa ula fusca tristiA it. drarki Alici a ,1nali lat ,st.
3..2.. 51.85 66.7%
267 174 2 443
Hickory 60.14 3q.34 _______ __ ,. __ ___
26 3.0o 9.7% 82.0%o 33.3%
18 10 14 50 1 93
ur oak 19.4% 10.71% 15.1% 53. __________ _____
Red oak1
.316 --
1 1
White oak 100.0561i-b
3.4% 20.8% 18.0" 6b.7
24 70 11 2 107
Black oak 22.46 65.4 _____ 10. 31 .....___
Aspen 33.6% .95% 4.s8 93.6% 20.0%
and 235 3 7 103 3 351
Eopu__, 66.91 .854 2.0 29.3% .8 4
5.7% 63.45% 60.5 14.3% 100.0%
40 92 9 1 1 143
Dogwood 28.0 ____ 64 _-.i 7____ .7-46
5.0% .9% 6.4
35 3 8 7 53
Willow _....Qj 5.175 15.15% .132
5.95% 19.34 9.05% 20.05% 33.35% 85.75%
41 b5 13 3 1 6 129
Hasel 3.8$1 5L.44 10.-146 ---2.L3 .8% 4.6%6________
6 5 11
HBi___ 5Aj ____ 4 ___ ___ -__ _-_ ___- _
.1% 1.4%
1 2 3
Rose 1_ ___ 66.74
3.45 .356 .--
24 1 1 26
qInflower q. 3.8 3.- -,, U.-

1 2 3
Thorn apple 33.34 66.7
.75% 1.8-% 1.54%
5 6 2 13
Butternut 8.55gL6 46,g5 15. 4 -
.15%
1 1
Dogbane 1l00.04
.1%
Balm-of- 1 1
Gilead 100.04 .______
.7%6
1 1
Raspberry 1___ .00.6....____ ______ -
.3-
Black-eyed 1
Susan ____ 100.0%6__________________ _









- 231 -


Studies in 1936

Beetles emerging in 1936 in southern Wisconsin belonged to "brood
BU. Ordinarily this is the smallest of the three broods, but in certain
years,. such as 1936, the emergence of Phyllophaga tristis, which has a
P.,year cycle, has increased the magnitude of the flight of "brood B" con-
siderably. The methods of study were essentially the same as those used
in 1935 and insofar as possible beetles were collected from the sane groves.
Species of beetles other than P. tristis were scarce in 1936, and it was
necessary to examine a great many plants in each locality in order to obtain
them in any quantity. All plants in each grove -,ere examined carefully and
it is believed that alarge proportion of the beetles present were actually
collected. The scarcity of beetles did not nullify the value of these
collections but in some respects was advantageous, especially in the deter-
mination of host preferences, since it was not necessary to omit from our
calculations the large numbers of beetles which, in seasons of abundance,
cannot be collected or counted.

Flight...The collection of beetles and the study of flight were
hindercdby the occurrence of many cool nights, which prevented or retarded
the emergence of the beetles. Considering the season as a whole, however,
the flight of Phyllophaga tristis was very large. Beetles of this species
were found in great numbers in various parts of Dane and Lafayette Counties,
and many oaks, stripped or partially stripped by them, were observed in
these localities. Damage to oaks was reported from Jefferson and Waushara
Counties, and specimens were sent in by county agents and other persons from
Pepin, Trempealeau, Vernon, Sauk, and Eau Claire Counties.

The first flight of June beetles was observed on May 6 at Gays Mills,
but some beetles were taken from beneath leaves early in April.

It was estimated that over 95 percent of the beetles flying belonged
to the species Phyllophaga tristis and that over 95 percent of the beetles of
this species fed on oak. The flight of P. tristis continued until the end of
June but flight of the other species was practically over by June 10.

Phyllophaga tristis flew freely and mated earlier in the season and
at lower temperatures than did the other species. Mating was observed at
temperatures as low as 520 F. early in the season, but later this temperature
was too low for even a small flight. P. tristis usually began issuing from
the soil from 10 to 20 minutes earlier in the evening than did the other
species. Early in the season emergence began at about 7:30 p.m., but as the
length of the days increased emergence began later. With the exception of
that by P. tristis very little mating was observed and that observed occurred
late in the season.










.pectes,.Fourteen species of beetles were collected. The number of
individual beetles of each species and the percentage of the total that each
species comprised are shown in table 4. Beetles of Lhyllophaga tristi occur.
ring on oak, which, as indicated earlier, were. more numerous than all the
others combined, are not included, Of the additional species, P, rugoa was
most abundant and comprised 39.66 percent of the total of 1,021 beetles,
P, irnplicita was second in abundance and comprised 17,24 percent of the total,
P, fusca, P. futilis,and P, ilicis, respectively, constituted 9,60, 8,52, aid
,66 percent of the total, Together theso five species made up 81,69 perw
cent of the total, P, irticula. which was second in abundance in 1935, was
very scarce and comprised only 0,88 percent of the total, Most of the P,
futilij beetles were collected at Lament and most of the P,, ilicis beetles
at Gays Mills, P. spreta and P. prunina, which were taken in small numbers
in 1935, were not obtained in 1936,

Host Preferences, Table 5 represents a consolidation of all collect
tions made in 1936 and shows the host plants of the various spo-ies of beetles
and the percentage of the total of each species found on each host, as well as
the percentage of the total beetles represented by each species. Phyllophaea
tristis beetles on oak, which were many times as numerous as all other species
on all hosts, are not included. It should be noted in this table that some
species of host plants have beeri grouped, for example, "poplars except aspen"
and 4red oak group," On an actual species basis, therefore, the number of
host plants would be greater than that indicated,


W 232 0










233


Table 4..-Adults of Phyllophnga Collected in 1936

by species and. the percentage of the total

represented by each species


: Percentage
Species : Beetles of total
:Nuiber

P. rigosa----------------------------- 405 39.66
1
P. imnplicita---------------------------- 176 17.24

P. fsca-------------------------------- 9g 9.60

P. tristis'-1/---------------------- 90 .1

P. futilis------------------------------- .52

P. ilicis.-------------------------------- 6 6.66

P. niti-da ---------------------------- 44 4-31

P. drake i.------------------------------- 26 2.55
S

P. hirticula ----------------------------- 9 .

P. balia-------------------------------- 6 : .59

2. marginalise--------- ----------------- : 6 :59

P. inversa (Horn)----------------------- 3 .29
S

P. anxia -------------------------------- 2 .20

P. crenulata ---------------------------- 1 : .10

Total--------------------- 1,021 : 100.00


l/p. tristis beetles on oak not included.






- 234 ..


During the season 34 flights were observed in 10 areas as follows:
Gays Mills, Crawford County, 16 flights; Black Earth, Dane County, 2 flights;
Dane, Dane County, 2 flights; Waunakee. Dane County, 2 flights; Lament,
Lafayette County, 4 flights; Edgerton,! Rock County, 3 flights; Blue Mounds,'
Dane County 2 flights; Madison (Lake Forest), Dane Coumty, 1 flight; Madison
(Gregg Farm), 1 flight; Hancock, Waushara County, 1 flight.

Phyllophaga rugosa was, relatively speaking, common except at Lamont.
According to the classification of the table, it was taken from 21 kinds of host
plants. It fed predominantly on cultivated cherry, dogwood, aspen, basswood
(linden), white oak, oaks of the red oak group, bur oak, and ironwood, these
host plants furnishing 26.91, 9.38, 8.40, 9.15, 7.90, 7.16, 5.93, and 5.68 per.
cent, respectively,, and together 79.51 percent of the total. The cultivated
cherries, upon which many beetles were found, are at Gays Mills in a commercial
planting. Leaving out of consideration for the moment this host, the diversified
feeding habits of P. rugosa become apparent, for the maximum percentage from any
other hozt plant was 9.38 percent, from dogwood.

Phyllophapa implicita occurred in all the areas studied and was taken
from eight different host plants, willow, aspen, and other species of poplar
furnishing 94.32 percent of the total.

Phyllophaga fusca was taken from 15 kinds of plants, butternut,, aspen,
dogwood, and oaks of the red oak group supplying 26.53, 23.47, 17.35, -.Md 10.20
percent, respectively, and together 77.55 percent of the total.

Phyllo-haga futilis was taken from 12 species of host plMants, mostly
at Lamont. Prickly aehZ/ supplied 35.63 percent of the total. This host, to-
gether with plum, locust, elm, aspen, and hazel, yielded 83.9 percent of the
total. Only 6.9 percent of the total was taken from oaks, although these were
common in the areas where P. futilis occurred.
The number of Phyllophaga tristis beetles collected from hosts other
than oak was very small in comparison with the number observed on the oaks, but
19 species of host plants other than oaks were recorded. Some preference
appeared to be shown for birch, dogwood, and aspen.

Studies in 1937
Methods of study in 1937 were essentially the sane as those used in
1935 and 1936; however, some of the groves previously used were not suitable
for collection in 1937. These were abandoned and others were selected. In
the emergence of "brood C" of beetles in 1937, all species, as compared with
1935, were scarce, with the exception of Phyllophara hirticula, which is
normally abundant in this brood in Lafayette and Iowa Counties. On the other
hand, all species, with the exception of P. tristis, were more abundant in 1937
than in 1936. In 1938 tho flight will be a major one for all species, including
. tristis.

/The grove studied was north of Edgerton, in Dane County.
-6/The grove studied was south of Blue Mounds, near the border of Iowa County.
-)'Xanthoxylum aaericanum.















Rost~~ ~ ~ ~ plnt a:_ __ a: A:_ :__.0.a vA
I* a a
^ a g)
-4 S 4'4 -4 00 S -- C3 *o 4
>- s a 3 -a f -a T ~s
Betpat.. .5 .*S. ^ < oJ g_ S b (S oC 2S Ic8 '* *'9 '! SC
4.4 59.09% 1.02o 3.33% 2.27% 5o
18 1014 1 3 1 1 12B
Willow 14.p6? 81.25%.7% 2.34% ______ _____ ___82 ___.8 2j44 q_ 114
8.940 19.89 23.7? 1.2-2 6.90% 5.88% 2.27% 23.08%
34 35 23 11 6 4 1 6 120
S23 2.17 1.17 9.17A 5.00? 3.33% .83i 5..001 .. _._. 75 117
26.91% .5-K 1.2 3.335%
109 1 1 3 114 11-17
hrAM it.L .61 .88 .81 g 2.63__ 100
3.95 2.04% 6.67% 6 58.8 -olT 23.o0% 33.33%
16 2 6 6 9 O 18 6 1 95
Esl16.8W 2.11 6.32? 6.324 42.11t 1.95f 6.32 1.05% ___ 100.02 9.30
9-38. 17.35 13.33* 3.453% 22.73V 26.92?
38 17 12 3 10 7 87
Zoo 3.67 l._____ 54 13.79 3.45 11. 9.05% 9999% 8.52
4.A 26.53% 5.56% 10.29 2.27%
s18 26 5 7 1 57
Bttr 3.5 8 ___ 45.61 8.77 12,28 1.75 99.9_____ .58
7.16% 10.20% 5.75% 13.64% 3.85% 33.33% 33.33% o00
29 10 5 1 1 2 1 1 55
Soak mp 52.____ _____ 10.91 1.82% 3.64 1.82 1.82% 100.01% 5.39
5:93 .1 5.l4, ..54% 77.78 ~6.67T 33.33%
2 6 1 3 7 1 2 44
ftLr oak 654,55 6 __ 2.271 _____ 6.8s4 15.931 2,27 4._____ 1 100.01 4.31
8.15 1.11 5.881 6.82
33 1 i 3 41
Aswoo__ o80. 49 ____. __44 9.760 7.32 __ o 10.01o 14.02
10o.oo00% 35.63% ?
9 31 40
Prickly ash 22.9_12.%7.5 3.93
3"95% 6.12 11.76% 50.00% 33.33%
16 6 4 8 3 1 38
42 .5$ 1 0. 21.05% 1 7.9 _____ 2.63% ____ 1 3.72
7.90% --- 7 .o9 47.4-?
32 1 3 3 37
white oak 8 .7.70? _______ 8.1 i% _____ _____ _____ _____ 1.00 3.62
99% 15.34% 1.02% 2.22%
Poplar 4 27 1 2 34
(except a n) 11.76 79. 41 2.94% 5.88% 99.9991? 3.3-
5.8 57% 2.22% 2.94% 4 55%
23 1 2 2 2 30
Ironwood 76.67 3.33 6.66 6.66 6.66 _____ 99.98 2._ _
.49? 3.1% 1 02% 2.22% 10.34% 2.27% 3.85%
2 6 1 2 9 1 1 22
-A00__ ..... O0
_ _9. 27.27 4.599 9.09 40.91_1 5_ ____ -- 94---- 10.01%? 2.15
.25% 1:02% 3.33% 13.79% 2.27% 22.22%
1 1 3 12 1 2 20
________ 9 _____5_ _5S_____ S__---- _____________________________p? 1.96
17.78% 33.33% 33.33%
16 2 2 20




9 9
.57%1._____ 0_____ __4 ) _I-oot-- --.88
1 4 5
Arl.20ple "i 2D 100% .4____ ___ --

33
7%33 3 3.33- 33.33 99,99{ 29
3 3
1 1 100
Sunflower 5D 50 10 .2
Sianor1 90 __ ___ _______ ____ II ____-- --- --- --J___-- -
1.02? 3.85%
1 1 2
lllOll5
ooseber ______ _____ ____ __ _____ _____ ________0 .2
1.02
1 1
CharTT. Wil14 __0____ ___ ____ __ _________ ____ ______________0?

1 1
;29
DVTM 100% 10,% .1


lo -- lor 1 a9tI
10% 1%Pq- --17-7TiOD" 9.98% loo~ i12 9T IT~~W 9999 11-9 T
% 17 w9 44 6 13 42 1 2p2l
Total 39.6 l7.2 9.60 14 .81 666 4.311 |2.5 .8 .I ,59 .2 ij.1% 100.01? 100.02


+


-- ~ ~ ~ ~ ~ e ~ l r e f# . .. . . .. .. .. .. . .. .. .. .. .. . . .. .









- 235 -


Flipht.-.Observations on emergence and flight of the beetles agreed
essentially with those made in 1935 and 1936. Phyllophaga tristis emerged from
10 to 15 minutes earlier in the evening than did the other species and began
flight and mating earlier in the season. P. fusca also began emergence earlier
in the season but mated later. P. ilicis appeared late; was found mating but
rarely until late in the season; and, as indicated in rearing cages, began
oviposition later than other species. Small flights occurred at temperatures
in the low 50's but major flights occurred in the 60's and 70's.

There was considerable variation in the duration of the flight period.
On some nights the main emergence and flight to host plants was completed within
about 5 minutes and on other nights emergence and flight continued slowly but
more or loss evenly for almost an hour. Soil and air temperatures and wind
conditions, as recorded by us, do not explain this behavior.

Spocies..-Phyllophaga irticul, the predominating species, was abundant
in the Hollandale mand Lamont districts but rare at Gays Mills. P. ilicis and
P. rugosa were abundant at Gays Mills but less numerous elsewhere. As shown in
table 6, the five most common species, P. hirticula, P. fusca, P. ruzosa, P. '
ilicis, and P. implicita, comprised 39.31, 2 t4, 1.59, 7.21, and 3.68 percent,
respectively, and together made up 92.27 percent of the total. The solitary
specimen of P. spreta was taken from butternut at Gays Mills. Of the 7,280
beetles, 106 were taken at Gays Mills and g2 at Blue Mounds between the 1st and
18th of July, inclusive, and all the others before July 1. Because of their
scarcity, the beetles taken after July 1 were not classified in a separate table
as was the case with those taken in 1935.

Hnst preferences.._Table 7, which is similar to tables 2, 3, and 5,
showing the number of each species of beetles taken from each kind of host plant
(or related group of host plants) and the percentage of the total each species
comprised, is a consolidation of collections made during 52 flights in 10
districts in southwestern Wisconsin. Thirty-two flights were observed on 30
nights at Gays Mills and 21 flights on 19 nights in the remaining 9 areas. The
groves, where observations were mnde, were near t1p follo-Ting towns: Gays Mills,
Crawford County; Waunakee, Madison, Blue Mounds,-/ Dane County; Edgerton,9/ Rock
County; Hollandale, Iowa County; Lodi, Poynette, and Leeds, Columbia County.





8/ The grove was south of Blue Mound near the border of Iowa County.

/ The grove was north of Edgerton, in Dane County.










-236-

Table 6...Adults of.Phyllophaga collected in 1937

by species and the percentage of the total represented

by each species


Percentage
S'pecies Beetles : of total
SNumber

P.. hirticul .------------------------: 2,862 : 39.31

. fsca.----------------------------- 1,709 : 23.4S

P. ruosai-------------------------- 1,353 18.59

P. ilicis---------------------------- 525 7.21

P. iraplicita..---------------------- : 268 3.68

P. drakei---------------------------- 227 : 3.12
*
P. ris--------------------------- 121 : 1.66

P. nitida---------------------------- 92 1.26

P. crenulata ------------------------- 59 ,81

P. futilis--------------------------- 30 : .41

P. marginalis --------------- 16 : .22
- .anxia-------------------------- 12 : .16

P. prwiina ---------------------- 4 -05
P. prunia-a-------.-------------------- 1 .05
P. balia.. .. . . .. . .. . 0

P. spret.--------------------------- 1 ,01

Total...------------------------. 7,280 : 99.98
*








Table 7.-Beetles of Phllopbsgaa collected froam hoot plants, li'37


Holt Plants


Si I A


LI* Lii


9.3 12.35 5.91 43.43%6 9.1 .8. 8.-1 13.33% 37.50% 1- T 50.
1411 211 50 228 157 21 52 4 6 2 2174
asel 64.9016 9,711 3.686 10.49A ____ 7 722J ____ .97 2.39 .4 1 C' -1 t _-_i
20.27% 12.35 11.01 12.95 3.33 6.2-
550 211 149 6s 1 1 1010
lickora 57.43 14.1 6.75 __- .106 .106 -00 U,1f
2.05% 45.90% 2.86Z 1.49 16.67%
Cherry 35 621 15 4 2 b677
1..1 91.73) .__ _22. _.5% 100. 9.01
.24 18.61% 10-136 26-10) 1.12) 3.26 6.256 100% 100%
7 318 137 137 3 3 1 1 1 608
BLtttt.ut 1.151 52.3 22.53 22.5. 7 .9 .4__ -% 6___ 9 4 .l64 ___ .1 .l66 9,.96,5
8.1l% 13.52% 1.2 .44? 46.286 3.26) 6.25)
232 231 17 1 5i 3 1 541
AMgtnt, 42i 98 L.i 7~ ..3..14%_ i, 10.35% .55% __ _99.98 7.43
8.32% 5.7W 2.1 46 .%35 1.12% 1.32% 47.11% 1.091C .69 3.33% 3124.50)68i.53%6
235 150 29 2 3 3 57 11 1 2 1 4Z8
leakam 4.77. 30.74f0 9.94% .7l .671 .61% 11.68% .20 .e$ .. M ___ ..7 .
.77 8.79o1 3.25. 1.33% 35.07 3.52% 12.50%
25 150 414 7 94 6 2 330
S7.58 3 1 9.li 2.i 2 2.48 .61 -99.99 4.53





!.o5T io.oi% 6.25%7 io9
.38% 7.55% -5% .57% 20.70% .'3< 473 10.006 6.257-
11 129 8 3 47 1 41 3 1 24
_O__ 4.51A___ 4 S_.g7_ 'X l2W .23 __4 19 1.__ 12 .14% I.t 3.3!A
.10%) .59 2.00% 51.9 .b5. 6.25% I1. 7
3 10 27 13 2 2 1 2 185
illow 1.6 41 14.9c 74.s5 1.0o%.0 .5 1.08.% 99.9% 2.n4,
.458% 1.35% .75% 6.67% 25.00%
131 23 2 1 2 3 162
laGo. 4.2____ 1.231 ______i i 521.85%
3.70% 1.4D% 9O%^J .37% 4 13-33





106r ooh 4~a~ lS6 S9,- 15. 4.9 l,9 .649.i ,
lm 2.gK .71 .71* .71% ____2__ 1*,.
3.10% 5.10% .19% 5.227.
Poplar 53 69 1 14 137
Uggerot Aspen)l ____ *ig.g i64 .714 10.22 __ ___ __ __ __ ___ __ __ 99.99% 1.88%
i 1.05 4.1 190 .37 1.09%
15 57 10 1 1 97
Ironwood ____ 20.69% 6 1 1.15% 1.19% ________ __________ lj
2.11% 2.66% .95% o .1 3.33.
36 6 5 3 1 1
1e.93% .10. 1.524 2.44 6T. b.b7i2% -5.o8(.11%
-- --1;4 _77 -9 3
2 35 19 8 6 1 2 1 1 73
I. 4.21 26.0 .6 g.22 .____ 1.7 .-1 1.937% 1 .
11 35 9 2 1 59
oo. Lio___ 1.61 9.77 15.25 3.9 5_____99.9 .gi%
1 .57 23% 3.30
45 4 1 50
acrr _90.00____ _4 .1____ .00 ______1 .6t
.4 .23, 19.4% 6.25%
15 14 2 17 1 39
Bambr" 3g. VA 10.26t .1___ .1 3.592.5"_ 1_- 1 ,
.03% .99% 81% 1.33%
1 17 11 7 36
2.1% 4 14. __ 1-100 .4q
.0 13.3. 63T ..3
23 1 1 30
Iko~tCrC 76.6rt J 3.331 _________ [% 1.31t3.______7 9____ ...i99.9- .414%
.5 .7 3.39% 3.33%
13 13 2 1 29
cibam (Wild) 44.8% 44. 690 3. __________100.014 .4Q
lagi .37o 3.62)6
3 5 19 27
HIckorr (PIanut .25 11.1 18.5 7 7
.2"f .71 .071, .3
12 1 2 23
c4.78 S.17 4.* 14 .7061 100__________ 3
.24% .9 .07% 1.766 1.09)%
7 5 1 4 1 18
Rse 38.69% 27.7 5.56- 2.5.56 __A 9__ ____ -9.99% .254
.231M .07% .57%
1 3 2
Ash0.0 12.5f_ 37.5 -100% .11%
1.65% 2.17
2 2 4
Ilderbrr ______50.00 _____. 100
13j3%4
... l 100.00 lO .
.03 .3.39%
1 2 3
7q3.3vt 66.66% ___ ___ _9.99% .04%
.07%
2 2
Awl '100.004 -___ __.3
2.17%
2 2
Current (Wild) _____1_0__0______ -1---_ 100L
.1
2 2
Avol (Thomn) 100,00 1_____- -
.15)6
2 2
29"a 00.00 __ _.03
03%
sd rt 100 ____________00______ ____ ____ ____O .01t
1.69%6

1.695%
1l
Poison 1wx loo____t _____ ______.O
.06)6
1 1
Lout___ __ IilJi.06% __ ____ ___ ___ ____ __ ___ ___ --- -- ----- --1Q.1
L o u t10 4 It I2 i~ 'A 4 C L .0 1 4
99.t4lO.0" qq.99* 99.9a< 99t 'i lC'.A 100.( ^. % .zt hkc..x4 'Oc W '04 I ..XA iA...< .1 X 1
2862 1709 1153 5. a 27 U!1 12 L I 11 S'1
taoal )9.!1% 23.4.< 15.5C44 7.14 I 3.65W 3.l2W I 1.2A4 I .Bli .I .o ..| : | ,.


B
X!


9)
3


5


*I
K
* C









- 237 -


Phyllo1haga hirticula was taken from 21 kinds of plants. Hazel
supplied 49.30 percent of the total number of beetles taken. Hickory, oaks
of the red oak group, bur oak, and walnut yielded 20.27, 8.32, 8.11, and
4,58 percent, respectively, and together with hazel, 90.58 percent of the
total.

Phyllophaia fusca was taken from 27 species of host plants. Butternut,
bur oak, hazel, hickory, oaks of the red oak group, aspen, and dogwood supplied
g18.61, 13.52, 12.35, 12.35, -8.78t, 8.7, and 7.55 percent of the total, respec-
tively, and together ,81.94 percent. A diversified feeding habit was indicated
in 1937, a, in 1935 and 1936. This species did not feed heavily on cultivated
cherry, as it did in 1935.

Phyllophaga ruposa was taken from 21 kinds of host plants. Cultivated
cherry at Gays Mills supplied 45.90 percent of the total beetles of this species.
Hickory, butternut, hazel, poplars other than aspen, ironwood, and aspen yielded
11.01, 10.13, 5.91, 5.10, 4.21, and 3.25 percent of the total, respectively.
Together with cherry, these hosts yielded 85.51 percent of the total.

Most of the Phyllophaga ilicis adults were taken at Gays Mills. This
species was takon from 17 kinds of host plants, 'hazel, butternut, hickory, and
pignut hickory yielding 43.43, 26,10, 12.95, and 3.62 percent of the total,
respectively, and together 86.10 percent,

Phyllopihaga implicita was foundithroughout southwestern Wisconsin but
was rather scarce at Gays Mills. It was collected from 11 kinds of host plants.
Willow and aspen yielded 51.49 and 35.07 percent, respectively, and together
86.56 percent of the total.

Summary of collections, 1935 to 1937, inclusive

Since the population of various species of June beetles varies among
the different broods, it is desirable to summarize the populations of the
various species on the 3-year basis,

Table S shows the number of each species of beetle taken each year
during the period 1935-37, inclusive, the total number of beetles of each
species for the 3-year period, and the percentage of the grand total of
beetles represented by each species. Pbyllorhnga rugosa and P. hirticula
were taken in about equal numbers, these two species constituting 67.15 per.
cent of the total. P. tristis was probably as abundant as either of these
two species, but in 1936, when they were most abundant, they were more numerous
in areas where tall oaks predominated; consequently no samples of value cculd
be taken. In 1937 P. ilicis was among the six most abundant species, including
P. tristis, but in other years it had not been important.













239-



*;abl),e ..4Beetles of Phyllophaga.collected. 1935-37



Peies 1935 1936 193 Total
Species :__ 1935 : 1936 : 1937 : Total __


:Number :Number
0
I ^


:Number :Number : Percent
:< : *.


P. rupsa --------

P. hirt icula ...

P. fusca ------

P.. implicita--..-

Pe. ilicis .-----.

P. tristis --. .
S







P. drake ......-

P, nit ida ------

P. futilis -------

P. balia ..


P. crenulata.---
I











P. marginalis ---

P. anxia ------. -


P. spretas--.

P. prunina --.---


P. -inversa ....

Total ----
s


5.10 lo


405


*
*
3,936 9


2,1143 : 98
*

323 176
*

50 69

317 : 190
*

.26 26

23: 44
0

2S8 87


72: 6

3


6: 6
0
*
135 2

7: o

3: 0
0
o51


12,053: 1,021
*


0
I
I
I

S
0
S


S
4
9
S
S
I
S

I
S
I
0
0
I

I
0
I
I
I
I
S
S
I
S
0
3
S
I
S
0
S
0
S
0
0
S
0*


.1,353 : 6,s6l :

2,8g62 6,807
*

1,709 3,950
3

268: 767

525: 6435

121 528:

v:
227.: 279:

92: 159:

30: 145


1: 79


59: 63:

16: 28:

12: 27:
3

1: g
O

4: 7:

:0 35


* *


7,280: 20,354:
*


. itritis from oaks not included.
-P. tri t is from oakcs not includedd,


4


33.71

33.44

19.4i


3.77

3. 16

2.59

1.37

.7S

.71


.39

.31

.14


.13

o.04

.03

.01


99.99











- 239 -


The kinds of host plants from which most of the beetles were taken
durin- the 3-year period are shown in table 9. The number of beetles taken
from each host in eac: year, the total taken from each host during the 3-yea.r
period, and the percentage of the number of all beetles collected whichh each
hoct furnished, are also' given, Bur oak supplied 21.19 percent of the total
and hazol 14.07 percent. The nine species given '..g.ther supplied 85.55 per-
cent of the total beetles. These records are interesting, as they show the
importance of oaks, hickories poplars, cultivated cherry (when this is in
the midst of an infested area5, hazel, and dogwood, as hosts.

Table 9.-.Principal hosts from 1935 to 1937, inclusive,
and the total number of Phyllophaga beetles taken from eich



Species __ :1935 1936 : 1937 : Total
:Number : Number:!rnber : Number :percent

Bur oak...-------- 3727 : 44 : 541 : 4,312 : 21.19

Hazel------------ 594 : 95 :2,174 : 2,63 : l14.07

Hickory.- .._. : 1,461 35 :1,010 : 2,509 : 12.33

Cultivated cherry" 1,530 : ll4 677 2,321 : 11.40

Populus sp. --.-. 969 : 154 467 : 1,590 7.8O

W'.llow ----------. 977 12 1S5 : 1,290 : 6.34

Butternut.-_---- 239 57 6: og : 904 : 4.44

Red oak group---: 311 55 : 4gg : g54 : 4.20

Dog-ood.-----: 439-._.. j: 9 2444 : 770 : 3.78

Total, 9 hosts-: -- -- : 17,413 : g5.55

Total, all hosts: -- : : 20,354 : _





UNIVERSITY OF FLORIDA

3 1262 09244 6532


24o0

Dis cuss ion

These studies are important in their relation to the control of
beetles of the genus Phyllophaga by spraying their host plants. From three
seasons* -7ork it would appear that the control of the six predominant species
in southern Wisconsin would effectually solve the June beetle problem in that
region. These species are P. rugosa, P. hirticula, P. fusca, P. tristis, P.
implicita, and P. ilicis. The first four of these are considerably nore
abundant than the last two. P. tristis could apparently be controlled by
spraying oaks, especially bur oak, with an effective insecticide; P. hirticula
by spraying oaks, especially bur oak, and in some cases hazel and hickory as
well; P. implicita by spraying poplars and willows; and P. ilicis by spraying
hazel, butternut, and hickory. P. rugosa and P. fusca were found on a large
variety of host plants so the spraying of a single species, or even several
species, night not materially reduce the numbers of beetles of these species.
P. implicita and P. ilicis have raro'y, if ever, been encountered as grubs
in cur sample diggings in cultivated fields and these species may not be
important as pests of field czcps. Grubs dug fronm;pastures, grain stubble,
and corn have chiefly belonged to the species P. osa P. hirticula, P.
fusca, and P. tristis, although 7, futilis grubs are fairly common in Lafayette
Couimty, and the general destruction of adults of these species apparently
would solve'the grub problem.

There are still many obstacles in the way of spraying trees for control
of Juno beetles. In addition to the fact that no entirely satisfactory in.
secticide for June beetles has been found, there are many tall trees in southern
Wisconsin and spraying these requires the use of an efficient power sprayer
equipped 'ith lon, leads of hose; the host plants are often located in mixed
plantings near the tops of hills and sometimes at considerable distances from
water; and the groves where beetles tend to concentrate are often scattered.
One condition favorable for their destruction, however, is the tendency for
maximrun defoliation to occur where bur oaks are predominant.




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