some EFFECTS or Fumncmss
ON THE HONEY m

mammmwdmms.

MICHEGAN STATE UNWERSFW

Warren Pas-sans
1956

.v..":.

THESIS.

80m Emma-"rs or FUNGICIDES 01-; my: HONEY 13;:
I

BY

WARREN EéRSONS

AN ABSTRACT

Submitted in partial fulfillment of the requirements

for the degree of

MASTER OF SCIENCE
in Michigan State University

East Lansing, Michigan

Department of Entomology

fl . 4
/" ' ‘“ 1 f
Approved , [Lid/1 i:;jLi/”/J#¢x—1lmkx_

1956

Cv

THEE“

ABSTRACT

Many beekeepers have reported that certain fungicides
'were killing their bees. Therefore, fourteen fungicides
commonly used in orchards were tested.

The fourteen fungicides tested were Puratized, Tag 331,
Greg Fruit Fungicide 3&1, Phix, Coromerc, Zerlate, Pomasol,
Core SDD, manzate, Fermate, Phygon, Crag 658, Orthocide, and
Dithane 278.

The fungicides were first screened to discover if they
were toxic or not. This was done by feeding fungicides at
concentrations recommended for field use in a twenty percent
sugar solution to groups of bees held in small cages. A
number of trials for each fungicide indicated that Puratized
and Tag 331 were very toxic, killing fifty percent of the
bees within one day; Crag Fruit Fungicide 341 was toxic to
fifty percent of the bees within two days; Phix, Coromerc,
and Coro SDD were moderately toxic killing fifty percent of
the bees in from three to four days, while Zerlate, Pomesol,
Manzate, Fermate, Phygon, Crag 658, Orthocide, and Dithane
278 were slightly toxic or non-toxic.

Tests for contact effects to the honey bee were made
because of the possibility of bees coming in contact with
the spray while in the orchards. Puratized contact effect
in both trials killed fifty percent of the bees within two

days. Tag 331, Crag Fruit Fungicide 341, Zerlate, and Coro
‘SDD had an average contact kill within four days. Pomesol,
Dithane 278, Crag 658, Phix, Coromerc, hanzate, Fermate,
Phygon, and_0rthocide had no contact effect.

Field tests were conducted during two summers to follow
up the laboratory tests. During the summer of 1954, four
mercury fungicides were tested on fields of alfalfa and buck-
wheat. Puratized appeared to be the most toxic, followed by
Tag 331. Phix and Coromerc did not seem to be toxic in the
field.

Fourteen fungicides were tested on an alfalfa field
during the summer of 1955. Puratized, Orthocide, Tag 331, and
Coromerc appeared to be toxic, while Phygon was moderately
toxic. Phix, Coro SDD, Manzate, Crag Fruit Fungicide 341,
Greg 658, Fermate, Pomasol, Zerlate, and Dithane 278 appeared
to be slightly toxic or non toxic.

Because Puratized appeared to be the most toxic in all
trials, it was tested for the median lethal dose. The L. D.
50 in 2b hours was 50 micrograms, and in three days 37.5 micro-
grams, which indicated that Puratized was more toxic than many
insecticides.

Immobilization of bees by the use of laughing gas or
freezing temperatures was not used because the bees' life span
was shortened in a number of the trials.

To find the effect of humidity on the life of a honey bee,

a Thelco cabinet was used to hold the bee cages and control

the humidity and temperature. High humidity decreased the
bees' longevity, while low humidity increased it. Because
humidity did not seemingly affect the bees' life enough to
interfere with the fungicide feed trials, it was more prac-
tical to hold bees at room.temperature without controlling
humidity .

SOME EFFECTS OF FUNGICIDES ON THE HONEY BEE

BY

WARREN PARSONS

A THESIS

Submitted in partial fulfillment of the requirements

for the degree of

RMSTER.OF SCIENCE
in Michigan State University
East Lansing, Michigan

Department of Entomology

1956

ACKNOWLEDGEMENT

The author wishes to express his appreciation to
Professors Ray Hutson, E. C. Martin, and.Herman King
whose interest and guidance made the completion of this
problem possible. He is also grateful to Mr. Donald
Cation and Mr. William.YOung of the Botany and Plant
Pathology Department and Mr. M. A. Breazeale of the

Physics Department of Michigan State University for
their assistance and the use of materials and equipment.

TABLE or commas "
Page
I INTRODUCTION........................................l
II REVIEW OF LITERATURE................................3
III METHODS AND MATERIALS...............................9

materials USBdoccoc00000000900000.0000...0000000009

B668............................................9

Fun-giCidGSOOOOOOOOOOOOOOOOO00000000000000.0000010
Experimental Methods..............................9
Preliminary experiments.........................9
Immobilization of bees with laughing gas......9
Immobilization of bees by freezing...........ll
Effect of humidity on the honey bee..........ll
Feeding bBGS in 08893000000000.0000...coo-0000012
contaCt effeCt 0f fungicideS...................13
Field teSt Of fungiCIdeS.......................lh
Median lethal dose of Puratized to the
honey beeooooooooooooooooooooooooooooooooooooolh

PlateSOCOOOOOOOOOOO00.0.0.000.0.00...0000...,0...15

Iv MERIWIJIEJAL RESULTSCOOOOOOOO0.000.00.00.000.00....19
TablGSOCOOOOOOOOOOO0....00....0.00.00.00.0000000020

v DISCUSSIONSOOOOOOOOOOOOOOOOOOOOOO0.0000000000000000M
Prelbminary'Expertments..........................h5
Immobilization of bees with laughing gas.......45
Immobilization of bees by freezing.............h5

Effect of humidity on the honey bee............h6

Feeding Trials...................................h6

COHtflCt EffeCt Of Fungicides.....................h7

b‘ield TeStSOOOOOOOOOOOOOOOOO...

00.000.000.0000000000h8

Median Lethal Dose of Puratized to the Honey Bee....l.9
VISWHIMYOOOO00......OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOSO
VII LITEMTIIRE CI‘I‘ED...OOOOOOOOOOOOOOOOOOOO....0000.0.0.0.52

I. INTRODUCTION

The beekeeping industry, as well as the growers of at
least fifty agricultural creps, are continually faced with
the problems of chemical warfare waged against harmful in-
sects. In addition to killing a number of colonies of bees
or seriously reducing the field force of bees, chemicals
kill many other beneficial pollinating insects. Therefore,
both the honey industry and the various cr0p producers who
depend on pollination suffer losses to their crops. All
chemicals used to control harmful insects should be studied
as to their toxic effect on beneficial insects, in order
that certain materials can be avoided or at least used with
care.

The comparative toxicities to the honey bee of fourteen
commonly used fungicides have been determined by both labor-
atory and field tests. To determine the toxicity of fungi-
cides in the laboratory, specific amounts were fed in a
twenty percent solution of sugar syrup. The contact effect
of the fungicides was tested by spraying bees held in cylin-
drical cages with a field-recommended Spray. Field tests
were carried out by exposing caged bees to blossoms which
had been sprayed with a recommended field application of the

fungicide.

To facilitate handling the bees quickly and easily,
various methods of immobilizing the bees were investigated.
Nitric oxide and freezing temperatures were used to immobi-
lize bees.

An investigation of the effect of humidity and temper-
ature on the life of the honey bee was made to find the

ideal temperature and humidity in which to hold cages of

bees.

II. REVIEW OF LITERATURE

A review of the literature on bee poisoning indicates
that many workers have investigated insecticides, while
little work has been done with fungicides. Shaw (1941)
wrote a review of bee poisons other than fungicides.

Borchert (1930) investigated the action of commonly
used copper compounds, copper sulfate, and basic copper
carbonate on bees. He found the lethal dose for a bee was
about nine micrograms of metallic cepper. Herman and Brit-
tain (1933) reported that copper fungicides under field con—
ditions had not yet been proved to cause death to bees.

When fed to bees, or when wet weather prevailed, they some-
times caused death.

Hildebrand and Phillips (1935) found that copper sulfate
was poisonous to bees, but that it was also a repellent.
From their tests they could not predict the damage to bees
which might result from.the application of copper sulfate to
the Open fruit blossoms. Shaw (l9hl) reported that results
indicated that copper sulfate at the rate of two pounds to
fifty gallons of water was poisonous to bees. However, his
casual observations in orchards where these materials were
applied as sprays or dusts failed to reveal an appreciable

increase in the death rate of honey bees.

Meyers (19h?) reporting on a Conference of Fruit Growers
and Beekeepers pointed out that "Fermate" was thought to be
toxic to bees. However, little was known about its toxicity
to the honey bee and one grower had been using the material
for five years without bad results on bees. It was concluded
that more information should be obtained relative to the use
of this material and its effect on bees as well as the use of
other fungicides.

Dadant (1923) declared that lime sulfur and bordeaux
mixtures were repellent to bees. He stated that these mater-
ials mixed with insecticides, would prevent bees from sucking
up the poison. Bourne (1927) found a combined Spray of lead
arsenate, lime sulfur, and nicotine sulfate was repellent to
bees even when mixed with equal parts of honey. When only
lead arsenate and honey or lead arsenate, lime sulfur and
honey was fed to bees they accepted it readily. Nicotine
sulfate seemed to be the only repellent, since all combina-
tions not containing it were eaten freely. Butler (l9h3)
criticized Bourne's experiment because honey was used as a
powerful attractant. When the combined spray without honey
was Sprayed on blossoms in the greenhouse, the bees from a
three-frame nucleus were repelled by the blossoms. However,
the bees still worked the blossoms in considerable numbers,
and as a result the mortality was very high for three days

following the spray.

Herman and Brittain (1933) incorporated lime sulfur in
sugar syrup in the dilution ordinarily used in Spraying and
it was so repulsive that the bees refused to eat. Butler
(l9h3) also found that sugar syrup and lime sulfur was not
eaten by the bees.

Carter (1943) reported that no cases of poisoning with
lime sulfur had been observed in the laboratory or in the
field. He recommended that arsenical sprays should be carried
out in conjunction with lime sulfur after petal fall as the
lime sulfur acted as a repellent. Butler (19h3) found that
when one percent or stronger lime sulfur was employed in spray
mixtures, honey bee mortality was greatly reduced.

Cox (1916) fed sulfur syrup to bees and reported good re-
sults in the control of disease. Davis (1916) reported that
dusting colonies with sulfur killed both brood and bees. IHer-
man and Brittain (1933) found that sulfur applied to blossoms
in the form of dust caused pronounced dysentery. Under field
conditions it was believed that most of the bees recovered.

ShaW'(19hl) found that wettable sulfur dusted lightly over
combs containing unsealed brood caused considerable mortality,
and the eggs failed to hatch if sulfur was present in small
amounts in the cells. Shaw and Bourne (l942) conducted pre-
liminary tests which indicated that sulfur applied to the
blooms either as lime sulfur or as a dust reduced the number

of visits of bees. As a result of these tests, the question

was raised as to the advisability of applying sulfur dust

during bloom. Shaw and Bourne (l9hh) used a 300 mesh sul-
‘fur dust and the treatment gave a 100 percent mortality in
ten days as compared with 33 days for the check. This re-
duced life of the bees by about 67 percent. Such a reduc-
tion could result in a considerable loss of the honey crep.

Butler (1943) reported that as previously observed by
Herman and Brittain, syrup containing flowers of sulfur was
taken greedily by the bees. Little evidence of poisoning was
apparent until after six hours, although a few bees appeared
to have slightly distended abdomens and they constantly'made
cleaning movements with their legs. After twelve hours, there
were a number of dead bees. This number increased rapidly
during the next few hours.

Thurston (1956) pointed out that fungicides may have ad-
Juvant action when combined with insecticides.

In laboratory tests it is useful to immobilize bees for
short periods of time. Butler (1948) conducted tests to de-
termine the effect on the mortality of the bees by subjecting
them to cold temperatures, ether fumes, and to fumes of cal-
cium cyanide as well as clipping one pair of wings. He con-
cluded that the immobilization of bees by subjecting them to
low temperatures was satisfactory if only a very short period
of immobilization was necessary and if sufficient exposure to

cold was used. Clipping of the wings did not seriously affect

O"\

the rate of mortality. The result of the test using calcium
cyanide, indicated that the clipping of a wing did not influ-
ence the mortality greatly, but the treatment by calcium cya~
nide greatly increased the mortality so that this method was
unsatisfactory as the bees were not sufficiently immobilized.
They regurgitated their honey and became sticky, and this
treatment caused a high rate of mortality with both clipped
and unclipped bees.

many workers use similar methods for holding and feeding
bees while testing the effects of chemicals. Eckert (1949)
has done considerable work with the chemical effects on the
honey bee, and therefore, his methods for holding and feeding
bees were reviewed. Eckert dissolved a known weight of mater-
ial in a given amount of 95 percent alcohol, than specific
amounts of these solutions were added to definite amounts of
a twenty percent sugar syrup. The probable toxic range of the
chemicals was determined by feeding different concentrations
to thirty to fifty bees in 4" x 5" x 3/4" cages. The solu-
tions were fed from inverted vials which were closed with
paraffined paper perforated with a small hole. After the
probable toxic range was determined, other bees were then
placed in queen cages and fed Specific amounts by the use of
micropipettes. Amounts fed varied from .005 to .03 m1. and
concentrations were varied.

WoodrOW'(l935) studied the effect of relative humidity

on the honey bee and found that in the range studied, bees
lived longest at a relative humidity of 25.52 percent. A
constant temperature of 70.21 degrees C. was used for each
relative humidity. He concluded that a high relative humid-
ity tended to shorten the bee's life, due to a difference in
the ability of the bees to eliminate water through tranSpira-
tion.

With reference to the penetration of aqueous solutions
into the thoracic tracheae of the honey bee, MbGovran (1929)
found that when surface and interfacial tensions of aqueous
solutions were reduced to the proper point, actual penetration
of the respiratory system.occurred. Brown (1951) reviewed the

general subject of tracheal penetration by spray liquids.

8

 

~£l‘ll‘llil.llli

III. METHODS AND MATERIALS

A. Materials Used
1. Bees

Honey bees Apis mellifera L. of the Italian race were

used in testing the effects of fungicides.
2. Fungicides

The fourteen fungicides tested for their effects on the

honey bee are listed in Table l.
B. ExperrmentalIMethods
1. Preliminary Experiments

a. Immobilization of bees with laughing_gas. To handle
bees quickly and easily, laughing gas (nitrig oxide) was used
to immobilize the bees. Laughing gas was produced by placing
a tablespoon of nitrigjoxide in a lighted bee smoker. A
yellow gas was produced along with smoke as the bellows of
the smoker were compressed. The gas was then blown into the
beehive for a few minutes until the bees became immobilized.
Then the bees were placed in holding cages and fed a twenty
percent sugar syrup from inverted glass vials. Mortality
counts were taken daily to evaluate the effects of the gas.

b. Immobilization of the honey bee bygfreezing at a
temperature of minus 1.4 degrees centigrade for 15 minutes.
Bees were shaken from combs through a funnel into package

bee shipping cages as shown in Plate I. The cages were

9

 

ll...lalin'1ll¢ll' I III ' ll.

TABLE 1

THE COMEDN NNME, CHEMICAL NAME, TRADE NAME, AND
MANUFACTURER OF THE FUNGICIDAL CHEMICALS TESTED

 

 

Common Name Chemical Name

Organic
mercury

Glyodin

Ziram

Ferbam

Mhneb

Quinones

Captan

Zineb

Thiran

Phenyl mercury
acetate

Phenyl mercury
acetate

N-phenylmercuri-
ethylenediamine

Phenylmercuric
acetate

2-heptadecy1-
glyoxalidine

Zinc dimethyl-
dithiocarbamate

Sodium dimethyl-
dithiocarbamate

Ferric dimethyl-
dithiocarbamate

Manganous ethylene
bisdithiocarbamate

2,3-dichloro-l,4-
naphthoquinone

Copper zinc
chromates

N-(trichloromethyl-
thio)-4-cyclohexene-
1,2-dicarboximide

Zinc ethylene-
bisdithiocarbamate

Tetramethylthiuram
disulfide

10

Trade Name and Manufacturer

Puratized Apple Spray
Gallowhur

Tag 331
Calif. Spray Chemical

Coromerc

Pittsburg Plate Glass
Phix

Chemley Products

Crag Fruit Fungicide 341
Carbide and Carbon

Zerlate
Du Pont

Coro SDD
Niagara

Fermate
Du Pont

MSnzate
Du Pont

Phygon
U. S. Rubber

Crag 658
Carbide and Carbon

Orthocide

Calif. Spray Chemical
Dithane 278
Rohm.and.Haas

Pomasol
Naugatuck Chemical

then placed in a freezing room for fifteen minutes at a
temperature of minus 1.4 degrees centigrade. When the bees
became immobilized, they were placed in small holding cages
and kept at room temperature. The small holding cages were
fitted with inverted vials filled with a twenty percent sugar
syrup for feeding the bees. Mortality counts were taken
daily.

0. Effect of humidity on the honey bee. To find the
effect of humidity on the life of a honey bee, a Thelco cab—
inet was used to hold the bee cages and control temperature
and humidity. Different salts were dissolved in tap water to
vary the humidity, while the temperature remained the same.
The salt solutions were then put in a 12" x 17" x 2" porcelain
pan and placed on the bottom of the control cabinet. Temper-
ature was set and controlled by the cabinet's built-in elec-
tric thermostat. (A hydro-thermograph was used to keep an
accurate record of temperature and humidity.

Bees were shaken from combs directly into wooden screened
cages 5" x 5" x 5" as shown in Plate II. A twenty percent
sugar syrup, made with distilled water, was available to the
bees at all times. The syrup was fed through an inverted
60 ml. glass vial covered with a perforated aluminum cap.

The equipment used for the humidity and temperature trials
is shown in Plate III.

11

2. Feeding Bees in Cages

In the initial test, a group of bees were shaken from
combs through a package bee funnel into standard bee shipping
cages, as shown in Plate I. Each cage was fitted with a door
at the end so that a row of wax queen cups could be moved in
and out for feeding. This method was later replaced by the
use of inverted vials, covered at one end with wax paper with
a few pin-point holes for feeding, and fitted in a hole on
top of the cage.

Later, the regular shipping cages were cut in half, and
50 to 200 bees were placed in the smaller cages. It was
difficult to count the dead bees as they accumulated in this
type of cage. Therefore, a wooden screened cage 5" x 5" x
5" with two sliding bottom boards was devised to facilitate
filling the cages, counting, and removing the bees as shown
in Plate IV.

Fourteen of the fungicides being used on fruit trees
and other crops which require pollination were fed to bees.
These materials included Puratized, Tag 331, Coromerc, Phy-
gon, Fermate, Manzate, Orthocide, Dithane 278, Crag 658,
Crag Fruit Fungicide 341, Zerlate, Pomasol, Phix, and Coro
SDD. The concentrations of the materials used were compar-
able to field recommendations and were fed directly to the
bees in a twenty percent sugar syrup. Ten trials were made
for eight of the fungicides which seemed toxic while five

trials were made for the other six fungicides which appeared

12

slightly toxic or non-toxic.
3. Contact Effect of Fungicides

The contact effect of fungicides on honey bees was
tested by spraying bees held in cages. About 50 to 100 bees
were shaken from combs into cylindrical wire screened cages
two inches in diameter and five inches long as shown in
Plate V.

The fungicides were Sprayed through the cages in a De-
Vilbiss Spray chamber in the entomology greenhouse as shown
in Plate VI. The Spray chamber is constructed with an exhaust
fan that carries the fumes and excess spray outside the build-
ing. The cages were placed approximately two feet in front of
the spray gun for ten seconds or until run-off occurred around
the cages. The cages were held with one hand and gradually
turned. In this manner complete and even coverage was obtained.
The materials were applied at thirty pounds pressure with an
atomizer type Spray gun. The Spray solutions were mixed in
150 milliliter Erlenmeyer flasks and were kept constantly
agitated by a magnetic mixer. The suction tube of the spray
gun was immersed in the spray solution in the Erlenmeyer
flask during application of the spray material. Cages of
"check" bees were Sprayed with tap-water and were used for
comparison with fungicide—treated bees.

After spraying each cage with a fungicide, the bees were
removed and placed in holding cages 5" x 5" x 5", and fed a

twenty percent sugar syrup. ‘Mortality was recorded each day.

13

4. Field Test of Fungicides

To follow up the laboratory test, field tests were
made to observe the effects of the fungicides on bees in
the field. During the summer of 1954, five wire screened
cages, 4' x 4' x 6' as shown in Plate VII, were set up in an
alfalfa field for two trials and then moved to a field of
buckwheat. The following summer, fifteen cages were set up
in an alfalfa field. Each cage had a two frame nucleus of
bees with a piece of cheesecloth Spread before each entrance
to facilitate counting the dead bees. The crop in each cage
was sprayed with the recommended amount of fungicide and a
record was kept of the dead bees. The cages were moved to
new areas of the field, free from chemical materials, for

each new trial.

5. Median Lethal Dose
of Puratized to the Honey Bee

If a fungicide is found to be toxic to the bees by feed-
ing field recommendations as in part A, a Specific amount may
be fed to find the median lethal dose. This may be done by
placing a micropipette at a sixty degree angle over an indiv-
idual queen mailing cage containing one worker bee, as shown
in Plate VIII. A Specific amount of fungicide is dissolved
in a twenty percent sugar syrup made with distilled water,
and drawn up into the end of the micropipette. If the bee is
held in a cage without food for several hours, it will read-

ily suck up the fungicide in one feeding. After the bee

1h

sucks up the required amount of fungicide, a wax cup in the
cage is filled with a twenty percent sugar syrup for addition-
al feeding. Ten trials for each Specific dosage were made

until the median lethal dose was found.

15

'J ' 1.

~’

V'W'

-. "\_r"

 

V \ ,i .‘_V -_ a, _ ~ A
‘ ¥ ' _~"*\ 0‘ A-,—\ \N--~\ 2‘- v_r

Plate I - Funnel for putting bees in cages

\_

 

.. A M,,M4\v~l\—\_/\ r¥d\ Mx~x~x~yx‘\4‘4‘\kMI\w~~\—V—<

Plate II - Bee cages used for feed trials

16

r; ,

w»- “

-u ’ .

.

I

1.

,.

. i .n

.

——_—._-___—_—.—.-
- - - .— - ‘

é“

 

 

 

 

,\—-‘_ \ \ -\1\ \\ .» -—\_.»—\ ,-g_\ ’\_-.

 

Plate IV - Shaking bees into cages

17

- "V’JV— ',

 

Plate V 7 Cages used for spraying bees

\/ _/ ,1 /

 

F/‘i / /- /' 1'

,~__\A.- MM M~~N~¥'\A— MaVW‘M M W\\. '\,~_,-"\-

Plate VI - Apparatus used to spray bees in cages

18

 

Plate VII - Cages used for field tests

 

IM- ‘\\.¢ \iw \M xfi \.,~‘\_,\ ‘._,\\,V\l.~“-\ s\~‘\~.~ \x w\_wl\_.—\ Nd

Plate VIII - Micropipettes used to feed individual bees

l9

/ _

IV. EXPERIMENTAL RESULTS

20

TABLE 2

DAYS REQUIRED TO KILL FIFTY AND ONE HUNDRED
PERCENT OF THE BEES WHEN IMMOBILIZED WITH LAUGHING GAS

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Twenty percent sugar syrup was fed to bees.)

 

 

 

Hours Required for Hours Required for

Repl. No. of Bees 50% Mortality 100% Mortality

1 67 5 l7

2 48 23 37

3 50 9 25

z, 56 12 a 26

5 51 1 l8

6 76 2 21

7 70 l 19

8 53 l 15

9 50 5 16
10 61 7 l4

 

TABLE 3
DAYS REQUIRED TO KILL FIFTY.AND ONE HUNDRED
PERCENT OF THE BEES WHEN IMMDBILIZED BY FREEZING AT A
TEHPERATURE OF MINUS l.h DEGREES CENTIGRADE FOR 15 MINUTES

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.)

 

 

 

Days Required for Days Required for

Repl. No. of Bees 50% Mortality 100% Mortalityw
1 #7 A 16
2 52 9 16
3 114 8 1a
4 82 10 2A
5 129 8 25
6 267 15 36
7 230 16 no
8 BAD 18 LO
9 128 12 39
10 130 A 30
11 A2 11 22
12 50 13 21
13 #7 7 23
1h #2 4 1h

 

22

TABLE 1v

DAYS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT OF
THE BEES WHEN EXPOSED TO VARIOUS HUMIDITIES AND TEMPERATURES

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.)

 

 

 

 

 

 

 

 

 

 

Repl. No. of Bees Humidity; Temperature 5ggrtaliigq%

1 80 7O 78 10 26

2 A7 70 78 8 19

3 133 70 78 12 25

1 2h? 70 78 20 27
Average SA102 7o 78 12 24

1 A9 90 80 5 11

2 50 9o 80 6 11

3 61 9o 80 5 11

4 27 9o 80 6 11

5 3h 90 80 2 12

6 24 9o 80 6% 8
Average #0.8 90 8O 5 11.3

1 87 76 so 12 ‘I25

2 108 76 so 13 31

3 110 76 8O 11 25

a 68 76 80 13 25
Average 93.2 76 80 12.2 26.5

1 RIP 111-H—’ 5o 80 15 31

2 108 ,50 80 17 32

23

TABLE h Continued

 

 

 

' . . lbrtalitg M
Repl. No. of Bees Humidity‘ Temperature 59@ 1 qb

 

 

 

l 178 30 80 9 28

2 183 30 80 A 31

3 27A 30 80 14 Ah
Average 211.6 30 80 9 3A.}

1 166 80 80 ll 27

2 18h 80 8O 10 32

3 275 80 80 9 29
Average 208 80 80 10 29.3

2h

TABLE 5

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMVMDATION OF PURATIZED

(Groups of bees were held in 5" x 5? x 5" wooden screened cages.
Concentrations of .150 ml./% pt. were fed to bees.)

 

 

 

 

 

Hours Required for Hours Required for
Repl. No. of Bees 50% Mortality 100% MDrtality
1 6)... 20 30
2 38 7 l9
3 31 15 28
4 307 8h 192
5 38 8 23
6 300 32 72
7 152 8 72
8 53 5 11
9 '208 2A ‘ 6o
10 188 1a' 60
Average T775 21.7 ‘“ 55.7

 

25

TABLE 6

HOURS REQUIRED TO KILL FIFTY.AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF TAG 331

(Groups of bees were held in 5" x 5" x 5” wooden screened cages.
Concentrations of .150 m1./é pt. were fed to bees.)

 

 

 

 

Hours Required for Hours Required foi—
.32211: No. of Bees 50% mortality 100% Mortality
1 #1 10 35
2 31 19 36
3 345 56 168
h #1 18 30
5 92 8 4h
6 1.00 21. 96
7 62 . 16 30
a 336 26 72
9 338 28 72
10 lh6 22 96
Average 183.2 22:7 67.9

 

26

TABLE 7

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED
PERCENT OF THE BEES WHEN FED A FIELD RECOMMENDATION OF PHIX

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .07/gm./% pt. were fed to bees.)

 

 

 

 

.Hours Required for Hours Required 53?—
Rgpl. go. of Bees _50%1Mortality 100% Mortality
l 35 32 1A8
2 2h 97 171
3 321 105 216
A 35 33 lhh
5 102 52 173
6 109 38 , 110
7 176 73 168
8 24h 7b 168
9 162 70 192
10 237 72 216
AverageAE 151:5 64.6 170.6

 

27

TABLE 8

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF COROMERC

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .07/gm./% Pt. were fed to bees.)

 

 

 

 

HoufEEREEuirédifor Hours Required f3?
Repl. No. of Bees #50% Mortality 100%2M0rtalityg
1 '57 144 192
2 38 1A0 195
3 295 106 195
1 84 62 184
5 151 78 182
6 96 72 120
7 364 90 ‘ 288
8 193 84 288
9 211 72 312
10 197 96 408
Average 168.6 94.4 239.0

 

28

T f! BI I!» 9

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF PHYGON

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .28 gm./% pt. were fed to bees.)

 

 

Hours Reqfiired for Hours Required for

 

 

Repl. No. of Bees 50% Mortality 100% Mortality
1 63 180 288
2 75 120 408
3 139 144 696
4 124 ‘ 60 288
5 129 228 864
6 384 222 .504
7 299 264 912
8 178 288 840
9 333 270 672
10 111 312 960
Average 9183.5 208.87 643.2

 

29

TABLE 10

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT OF THE
BEES WHEN FED A FIELD RECOMNENDATION OF CRAG FRUIT FUNGICIDE 341

(Groups of bees were held in 5" x 5" X 5" wooden screened cages.
Concentrations of .43 gm./% pt. were fed to bees.)

 

 

 

 

I Hours Required for Hours:Required f3?
Repl. No. of Bees ‘5Q%IMortality 100%Mbrtality
1 9O 25 72
2 122 24 72
3 154 67 168
4 103 41 88
5 193 62 160
6 86 42 160
7 153 46 136
8 103 40 88
9 105 48 88
10 173 46 88
Average 128.2 44.1 102.0

 

3O

TABLE 11

(HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION.OF ORTHOCIDE

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .43 gm./% pt. were fed to bees.)

 

 

Hours Required for Hours Required for

 

 

Repl. No. of Bees A50%2Mortality 100% Mortality
l 110 504 792
2 86 408 768
3 40 528 576
4 67 312 768
5 96 3 36 816
6 179 318 768
7 180 548 812
8 112 528 760
9 92 348 793
10 137 420 776
Average 108.14 422.0 756.4

 

31

TABLE 12

HOURS RE-';¥IJIRED TO KILL FIFTY AND ONE IRINDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMENDATI ON OF CORO SDD

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of 4.5 m1./% pt. were fed to bees.)

 

————

 

 

 

R021. No. of Bees ESEEEoggggiigq for ESUESMEEEEEEE§ for
1 159 38 230
2 157 54 144
3 193 132 240
4 128 119 216
5 619 215 312
6 63 143 240
7 142 72 144
8 162 108 192
9 78 54 144

10 11“ 36 120

Average 181.6 97.1 198.2

 

32

TABLE 13

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A.FIELD RECOMMENDATION OF MANZATE

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .43 gm./% pt. were fed to the bees.)

‘—
.—

 

 

 

Hours Required for Hours Required for

Repl. No. of Bees _5Qfi Mortality 1002 Mortality

l 331 72 504

2 118 96 696

3 64 168 720

4 114 168 1056

5 126 600 1224
Average 150.6 250.8 840

 

33

TABLE 14

HOURS REQUIRED TO KILL IIFTY'AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION 0F FERMATE

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .43 gm./% pt. were fed to bees.)

 

 

Hours Required for "Hours Required For

 

 

Repl. No. of Bees _50% mortality gg 100%2Mortality
l 454 240 624
2 147 132 336
3 186 456 1272
4 62 228 744
5 329 336 1008
Average 235.6 290.4 796.8

 

34

TAEU315

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF POMASOL

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .43 gm./% pt. were fed to bees.)

 

 

 

 

Hours Required for Hours Required for

Repl. No. of Bees 50w Mortality lOQfi Mortality

1 ' 122 96 672

2 185 384 1104

3 117 312 1032

4 80 288 960

5 61 384 1122
Average 113 292.8 . 978

 

TABLE 16

HOURS REQUIRED TO KILL FIFEY.AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF ZERLATE

(Groups of bees were held in 5".x 5" x 5" wooden screened cages.
Concentrations of .43 Sm./% pt. were fed to bees.)

 

 

 

 

Repl. No. Of Bees ESEEEOEESEEEEd for gggismggggi§gg=EaFI
1 155 96 408
2 107 360 672
3 52 288 648
4 71 312 696
5 90 336 624
éyerage 95 278.4 609.6

 

36

TABLE 17

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF DITIIANE 278

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .43 gm./% pt. were fed to bees.)

 

 

Repl. No. of Bees

Hours Required for
5056 Mortality

Hours Required for
1002? Mortality

 

 

1 210 648 1200

2 93 768 912

3 188 504 1656

4 192 552 1296

5 156 624 1200
Average 127.8 619.2 1252.8

 

—.——

37

TABLE 18

HOURS REQUIRED TO KILL FIFTY AND ONE HUNDRED PERCENT
OF THE BEES WHEN FED A FIELD RECOMMENDATION OF CRAG 658

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.
Concentrations of .43 gmo/i‘ pt. were fed to bees.)

 

Hours Required for Hours Reqtifred for

 

 

Repl. No. of Bees 5 ‘7}; Mortality lOQ°/3 Mortality
l 80 264 504
2 113 96 648
3 114 96 696
4 254 144 1776
5 160 132 912
XReragé' 144.2 146.4 907.2

 

38

ABLE 19

HOURS REQUIRED TO KIIJ.FIFTY'AND ONE HUNDRED
PERCENT OF THE BEES WHEN FED A TWENTY PERCENT SUGAR SYRUP

(Groups of bees were held in 5" x 5" x 5" wooden screened cages.)

 

 

 

 

Reel- eLBeee eerei‘i‘e mid
1 1‘8 360 648
2 149 240 888
3 284 336' 792
4 126 312 552
5 183 78 720
6 230 A15 888
7 110 #08 - 768
8 54 120 288
9 178 192 66A
10 274 330 1056
Average 173.6 279.2 726.4

 

39

TABLE 20

AVERAGE RESULTS OF THE FUNGICIDE TRIALS

 

 

 

3.934.... No. of B... REEJEEEER f” REEEEEEW
Puratized 137.9 21.7 46.7
Tag 331 183.2 22.7 67.9
Crag 341 128.2 44.1 102.0
Phix 151.5 67.6 170.6
Coromerc 168.6 94.4 239.0
Coro SDD 181.6 97.1 198.2
Crag 658 144.2 146.4 907.2
Zerlate 95.0 278.4 609.6
Pomasol 113.0 292.8 978.0
MEnzate 150.6 250.8 840.0
Phygon 183.5 '208.8 643.2
Fermate 235.6 290.4 796.8
Orthocide 108.1 - 422.0 756.4
Dithane 278 210.0 I 648.0 1200.0
Check 173.6 279.2 726.4

 

4O

TABLE 21
CONTACT EFFECT OF FUNGICIDES ON THE HONEY BEE
(Bees were held in cylindrical wire screen cages, sprayed

for ten seconds, then placed in holding cages and fed sugar
syrup.

 

 

 

lst Trial 2nd Trial

Hours Required for No. of Hours Required for No. of

Fungicide Mortality Bees ‘Mortality Bees
5g% 109% 50g 100%

Puratized 36 696 96 30 336 101
Tag 331 142 552 107 36 552 63
Crag 341 115 600 116 40 432 93
Zerlate 54 144 67 48 312 133
Core SDD 48 187 92 67 139 85
Pomasol 120 504 67 264 672 132
Dithane 192 216 63 120 576 166
Crag 658 192 312 111 240 648 74
Phix 528 1008 139 264 1032 54
Coromerc 216 552 89 156 216 63
Manzate 264 528 84 142 288 116
Fermate 216 816 129 288 768 53
Phygon 284 480 60 140 384 114
Orthocide 312 624 77 288 528 76
Check 252 552 126 288 432 115

 

41

TABLE 22
MORTALITY OF BEES FROM MERCURY FUNGICIDES IN FIELD TESTS
(Summer of 1954)

 

”‘0'...“ fl»... .—

 

 

Mortality
Fungicide lst Trial 2nd Trial 3rd Trial 4th Trial
Tag 331 70 5 28 12
Puratized 54 100 22 100
Phix 300 21 37 8
Coromerc 11 1 3 14
Check 18 1 many due to

fighting

 

42

TABLE 23
NORTALITY OF BEES FROL FUNGICIDES IN FIELD TESTS
(Summer of 1955)

 

 

 

Mortality

Fungicide lst Trial 2nd Trial
Puratized 96 200
Orthocide 138 127
Tag 331 71 66
Coromerc 31 140
Phygon 33 52
Phix 9 11
Core SDD l 15
Manzate 11 188
Crag 341 4

Crag 658 38 6
Fermate 8 2
Pomasol 7 9
Zerlate 9 4
Dithane 278 8 3
Check 1 O

 

43

TABLE 24
MEDIAN LETHAL DOSE OF'PURATIZED TO THE HONEY BEE

(Specific amounts of Puratized were fed with micropi-
pettes to individual bees held in queen mailing cages)

 

Hours Required for 50% Mbrtality When Fed

 

Repl. No. of Bees 37.5 25 50 check
1 10 22 », 220 2A 109
2 10 88 196 23 128
3 10 88 184 24 no
A 10 88 #2 2h 72
5 10 72 88 24 48
6 10 67 leg 15 96
7 10 88 22 1M;
8 10 67 16 96
9 10 6h 21 196
10 10 67 31 188

 

Ah

V . DISCUSSION

#5

V. DISCUSSION

Preliminary Experiments

Immobilization of bees with laughing gas. Results of.
this test are recorded in Table 2. The average results of
ten trials indicate that the life Span of the bees was re-
duced greatly by exposing them to laughing gas. A number of
individual trials had a fifty percent mortality within 24
hours which would definitely interfere with the results from
chemical feed trials. For this reason, this method of immo-
bilizing bees was eliminated.

Immobilization of bees by freezing. The results of this
test are recorded in Table 3. A freezing temperature short-
ened the life Span of the bees as indicated by the average
of ten trials. In some of the trials, the life span did not
seem.to be shortened by the freezing temperatures while in
other trials it was definitely affected. This may be be-
cause of the length of time the bees were actually exposed
to the cold. When the bees were brought into the cold room,
they immediately formed a cluster. The bees on the outside
of the cluster became immobilized first, and were exposed to
the cold longer than the inside bees which became immobilized
last. It may be noted in Table 3, that the larger the number

of bees in a trial, the longer they lived due to the protection

46

of the cluster's heat. This method of immobilization was
not used because the results were not consistent. Freezing
did affect the mortality enough so that it could interfere
with feeding trials which were intended to test a chemical.

Effect of humidity on the honey_bee. Results of this

 

test are recorded in Table h. The test indicated that high
humidity decreased the bees' longevity, while low humidity
increased it. However, humidity did not affect the bees'
life enough to interfere with the fungicide feed trials.
Therefore, it was more practical to hold cages of bees at
room.temperature without controlling humidity.

Feed Trials

Tables 5 through 20 show the results of feeding fungi-
cides to the honey bees. The fungicide syrup was replaced
every few days to prevent spoilage and the wax paper was re-
placed to prevent leaking over the cage. Bees were consid-
ered dead if they were unable to move, and mortality counts
were taken at least once daily. The cages were kept at room
temperature. The humidity and temperature effect on the
honey bee is discussed under part c.

The average results of the feed trials indicated that
most of the fungicides are relatively non-toxic. However,
Puratized and Tag 331 were very toxic killing fifty percent
of the bees within one day. Crag Fruit Fungicide was toxic

to fifty percent of the bees within two days. Phix, Coromerc,

1+7

and Coro SDD are moderately toxic killing 50 percent of the
bees in from three to four days. Zerlate, Pomasol, Manzate,
Fermate, Phygon, Crag 658, Orthocide, and Dithane 278 are
slightly toxic or non-toxic.

In the case of the mercury compounds including Puratized,
Tag 331, Coromerc, and Phix, the bees were observed falling on
their backs, moving parts of their bodies slowly without prOper
co-ordination.

Ten cages of bees were set up without food, to find if
bees in the feed trials died as a result of repellent effect
of fungicides. Fifty percent died within one day, and 100
percent died in three days. This indicated that none of the
fungicides were repellent enough to cause complete starvation.
This was further substantiated when Specific amounts of the
fungicides were observed being sucked up from micropipettes.

Contact Effect of Fungicides

The results of this test are recorded in Table 21. Pur-
atized, Tag 331, Crag Fruit Fungicide 3tl, Zerlate, and Coro
SDD have some contact effect on honey bees. Pomasol, Dithane
278, Crag 658, Phix, Coromerc, manzate, Fermate, Phygon, and
Crthocide have no contact effect. Most of the bees in the
cage sprayed with Crag Fruit Fungicide 341 appeared wet and
could not fly or move very far. In view of McGovran's work
with bees (1929) and Thurston's observations on Crag Fruit
Fungicide 3hl (1956), it seems possible that tracheal penetra—
tion may have occurred. Bees Sprayed with water alone did not

show this reaction.

48

The time required for 100 percent mortality in the
cages, which were sprayed with toxic fungicides, was approx-
imately as long as the non-toxic materials. This may have
been because some bees received little or no spray.

Field Tests

Four fungicides were tested in the field during the sum-
mer of 1954, and ten additional fungicides were tested during
the summer of 1955.

Field test results for the summer of l95h are given in
Table 22. During the first trial, the weather was cold and
rainy which reduced blossom.visitation. A high mortality re-
sulted in the Phix cage because bees from a different colony
were placed in the nucleus and fighting resulted.

The second trial on alfalfa was not very successful be-
cause most of the blossoms were past the bloom stage.

The third trial was on buckwheat during cool weather.

A new nucleus was placed in the check cage and a high mortal-
ity resulted from the bees fighting.

Weather conditions during the fourth trial were ideal
and gave the best results. The cage which was Sprayed with
Puratized had the greatest mortality. Many bees were on
their backs or crawling around on the ground of the cage, un-
able to co-ordinate their legs, showing effects of the poison.

Because of unfavorable climatic conditions, bees did

not visit blossoms extensively. However, from the four

#9

trials conducted, Puratized appeared to be the most toxic fol-
lowed by Tag 331. Phix and Coromerc did not appear to be tox-
ic in the field.

Field test results for the summer of 1955 are given in
Table 23. During each trial, the alfalfa was in full bloom
and weather conditions were ideal for blossom.visitation by
the bees. Puratized, Orthocide, Tag 331, and Coromerc ap-
peared to be toxic, while Phygon is moderately toxic. Phix,
Coro SDD, manzate, Crag Fruit Fungicide 3hl, Crag 658, Fer-
mate, Pomasol, Zerlate, and Dithane 278 appeared to be
slightly toxic or non-toxic.

Median Lethal Dose of
Puratized to the Honey Bee

The results of this test are recorded in Table 2a. A
number of trials were conducted using different dosages to
find the median lethal dose. The tests indicated the median
lethal dose was 37.5 micrograms within a four day period and
50 micrograms within one day. When bees did not suck up the
fungicide from the micropipettes, it was found they would
draw it up more readily by increasing the sugar content.
Just before the bees died, they moved their legs with imr
proper co-ordination as they did in the feeding trials in

part B-2, which indicated the fungicide was affecting them.

50

VI. SUMMARY

Fourteen fungicides commonly used in orchards were
tested to see what effect they had on the honey bee.

The feeding trials in the laboratory indicated that
Puratized and Tag 331 were very toxic, killing fifty percent
of the bees within one day; Crag Fruit Fungicide 3A1 was tox-
ic to fifty percent of the bees within two days; Phix, Coro-
merc, and Coro SDD were moderately toxic, killing fifty per-
cent of the bees in from three to four days. Zerlate, Pom-
asol, Manzate, Fermate, Phygon, Crag 658, Orthocide, and
Dithane 278 were Slightly toxic or non-toxic.

Tests for contact effects to the honey bee were made be-
cause of the possibility of bees coming in contact with the
spray while in the orchards. Puratized in both trials killed
fifty percent of the bees within two days. Tag 331, Greg
Fruit Fungicide 341, Zerlate, and Coro SDD had an average
contact kill within four days. Pomasol, Dithane 278, Crag
658, Phix, Coromerc, Manzate, Fermate, Phygon, and Orthocide
had no contact effect.

Field tests were conducted two summers to follow up the
laboratory tests. During the summer of l95h, four mercury
fungicides were tested on fields of alfalfa and buckwheat.

Puratized appeared to be the most toxic followed by Tag 331.

51

Phix and Coromerc did not seem.to be toxic in the field.

Fourteen fungicides were tested on an alfalfa field
during the summer of 1955. Puratized, Orthocide, Tag 331,
and Coromerc appeared to be toxic, while Phygon was moderate-
ly toxic. Phix, Coro SDD, hanzate, Crag Fruit Fungicide 3A1,
Crag 658, Fermate, Pomasol, Zerlate, and Dithine 278 appeared
to be slightly toxic or non-toxic.

Because Puratized appeared to be the most toxic in all
trials, it was tested for the median lethal dose. The L.D. 50
within one day was 50 micrograms, and within three days 37.5
micrograms, which indicated that Puratized was more toxic than
many insecticides.

Immobilization of bees by the use of laughing gas or
freezing temperatures, was not used because they shortened the
bees' life span in a number of the trials.

To find the effect of humidity on the life of a honey bee,
a Thelco cabinet was used to hold the bee cages and control
the humidity and temperature. High humidity decreased the bees'
longevity, while low humity increased it. Because humidity did
not shorten the bees' life enough to interfere with the fung-
icide feed trials, it was more practical to hold bees at room

temperature without controlling humidity.

52

LITERATURE CITED

Borchert, A. Berliner tierarztliche Wochenschrift, h6z8h.
(Abstract in American Bee Journal. 70:327, 1930.)

Bourne, A. I. The Poisoninggof Honey Bees by Orchard Sprays.
massachusetts Agricultural ExperimentaIIStation, Bulletin
23h, 1927.

Brown, A. W. Insect Control by Chemicals. John Wiley and
Sons, New‘Ybrk and Chapman and'Hall, Limited, London,
1951.

Butler, C. G. Work on Bee Repellents: management of Colonies
for Pollination. Annals of Applied Biology;. 30:195-196,
19h3.

Butler G. D. Jr. Comparative Toxicity of Various Insecti-
cides to the Honey Bee. ITheSis presented'to the UnTVer—
sity of massachusetts, Amherst, Nbssachusetts, l9h8.

Carter, G. A. Orchard Spray Poisoning of the Honey Bee.
Annals of Applied Biology. 30:195, l9h3.

Cox, J. S. Nosema A is or Bee Paralysis. Cleanings in Bee
CUltureo ##328 -7, 19160

 

Dadant, C. P. The Editor's Answers. American Bee Journal.
63:2h8, 1923.

Davis, 0. S. A Successful Sulfur Treatment of Nosema Apis.
Gleanings in Bee Culture. 44:72-73, 1916.

Eckert, J. E. Determining the Toxicity of Agricultural Chem-
icals to Honey Bees. Journal of Economic Entomology.
42:261“265, 19h90

Herman, F. A. and w. H. Brittain. Studies in Bee Poisoning
as a Phase of the Orchard Pollination Studies. Cana ian
Department of AngcfiIture, BuIIetIn I62 (55:158-189, 1933.

Hildebrand, T. H. and E. F. Phillips. The Effects of Certain
Bactericides EsPecially Copper Sulfate on the Longevity
of Honey Bees. Journal of Economic Entomology. 28:559-
565. 1935 .

 

53

MbGovran, E. R. Surface Tension and Tracheal Penetration.
Apis Journal New York Entomology Society. 37:513-531,
1929..

Myers, H. Conference of Fruit Growers and Beekeepers on
Relationship of Spray Program.to mortality of Bees Used
for Pollination. Cleanings in Bee Culture. 75:15-17,

19h7.

Shaw, F. R. Bee Poisoning. A Review of the Mbre Important
Literature. Journal of Economic Entomology. 34:16-21,

19h1.

Shaw, F. R. and A. I. Bourne. Some Observations on the
Effects of Sulfur Compounds Applied During Bloom.on Bee
Behavior. JOurnal of Economic Entomology. 35:607-608,
l9h2.

Shaw, F. R. and A. I. Bourne. The Effect of Some Insecticidal
and Fungicidal Duets on Bees. Cleanings in Bee Culture.
72:125, 19th.

Shaw, F. R. and A. I. Bourne. Investigations on materials
Suggested as Bee Repellents. Gleanings in Bee Culture.
7h:77-79. 19h6.

Thurston H. W} Fungicides for Insect Control? American
Fruit Groweg. 76:65, 1956. __.__..___

Wolfenbarger, D. 0. An Attempt to Study the Effects of Rel-
ative Humidity on Honey Bees. Journal of Economic Ento-

mology. 27:638-6Ll, l93h.

Woodrow, A. W. Some Effects of Relative Humidity on the
Length of Life and Food Consumption of Honey Bees.
Jogpnal of Economic Entomology; 28:565-568, 1935.

Bureau of Entomology and Plant Quarantine. .Eguipment and
Procedure for Longevit Studies with Caged Honey Bees,
United States Department of Agriculture, Washington,
1938.

 

54

5,. 1?. pg,
1“!“13 3.!"

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K 4‘éL 1’sa

 

MICHIGAN STATE UNIVERSITY

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