PROTECTING HONEY BEES
Malcolm T. Sanford
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / J. T. Woeste, Dean
C.-j 'r IS
PROTECTING HONEY BEES
Malcolm T. Sanford*
The Importance of the Honey Bee
The honey bee is just one of the many kinds of
bees endemic to Florida. However, it is the most im-
portant bee to Florida agriculture and to that of the
United States as a whole. The honey bee is credited
with approximately 85% of the pollinating activity
necessary to supply about one-third of the nation's
food supply. Well over 50 major crops are either
dependent on these insects for pollination or pro-
duce more abundantly when honey bees are plenti-
ful. Although some beekeepers routinely supplement
their income by renting colonies of bees for pollina-
tion, most honey bee activity is a service provided
free of charge. This "intangible" benefit from the
keeping of honey bees, however, is no small contri-
bution to agriculture. In fact, it is estimated to be
somewhere between ten to twenty times the total
value of honey and wax produced by these insects.
There are an estimated 10,000 to 12,000 bee-
keepers in the state of Florida, managing a total of
350,000 to 400,000 colonies and producing between
20-30 million pounds of honey annually. Each year,
this industry is affected by use of chemicals called
pesticides, marketed to control populations of
weeds, plant pathogens, nematodes, insects,
rodents, birds, and other pests. This publication is
written to inform beekeepers, commercial growers
and the general public about the often complex re-
lationship between honey bees and pesticides and to
suggest how honey bees can better be protected
from the potential hazards of these chemicals.
Honey bees are vegetarians, usually consuming
only pollen and nectar from plant blooms or sweets
like sugar syrup and honey dew. These insects are
highly social and a colony may contain as many as
10,000 to 100,000 individuals, depending on the
time of year, prevailing weather conditions and
availability of nectar- and pollen-bearing blossoms.
Each colony consists of three kinds of individuals. A
single fertile queen is usually present to provide re-
placement bees, and there may be from a few to
several thousand drones. The latter are male bees
whose major function is to mate with virgin queens
to ensure survival of the species.
Finally, the vast majority of the bees in a colony
are sterile females called workers. As the name sug-
gests, they are responsible for doing all the work, in-
cluding gathering and processing food, caring for
the brood of young bees, defending the colony and
maintaining the colony's temperature.
Poisoning and Developmental Stages
Worker bees are those primarily affected by pesti-
cides. The symptoms of poisoning can vary depend-
ing on the developmental stage of the individual bee
and kind of chemical employed (see Figure 1).
] WORKER EMERGES BEE D ES
QUEEN LAYS EGG 3 WEEKS AS HOUSE BEE
1 3 WEEKS AS FIELD BEE
3 WEEKS IN DEVELOPMENT 5 WEEKS AS ADULT BEE
DEVELOPING LARVAE HOUSE BEES FEED ON FIELD BEES
KILLED BY CONTAMINATED POLLEN & NECTAR FROM FIELD KILLED BY DIRECT SPRAY OR
II I I I
FOOD (POLLEN, NECTAR) IF POISONED THEY DIE TAINTED WATER
1 2 3 4 5 6 7 8 9
Figure 1: The danger of pesticides to worker honey bees during their lifetime.
*Associate Professor and Extension Apiculturist, Department of Entomology, IFAS, University of Florida, Gainesville 32611.
Development of adult: It takes worker bees about
twenty-one days to develop from egg to adult. Dur-
ing this process, each individual passes through a
larval (feeding) stage followed by a pupal (trans-
formation) stage. The larval stage is the most sus-
ceptible to pesticide poisoning during development.
House bees: These bees are emerged worker
adults up to twenty-one days of age. They care for
the brood, process pollen and nectar gathered in the
field by older workers, and clean the nest. Eventually,
they too will become field bees. House bees are
usually poisoned by contaminated pollen which is
collected in the field, brought back and stored in the
hive. As house bees are killed, there are fewer bees
to tend the brood and further decline in population
Field bees: These bees are workers twenty-one to
approximately forty-two days of age. There appears
to be no greater risk in bee society than to be a field
bee. Should the insect avoid all the potential pitfalls
due to predators like spiders, toads or skunks, it is
still vulnerable at all times to the numerous
pesticides applied in commercial agriculture, mos-
quito control, and home gardens. Most times, field
bees are killed by contact with pesticides in the
field, but other times they collect contaminated nec-
tar and pollen and contribute to poisoning their
sisters in the colony. If field bees are killed, then
young bees are forced into the field earlier than nor-
mal, disrupting and thus disorienting the colony.
While foraging, field bees may range as far as two
to five miles from a colony. They usually seek nectar
and pollen systematically, not randomly, and once a
food source is found, bees prefer to work that par-
ticular source to exhaustion before changing plants.
This kind of resource partitioning by bee colonies ac-
counts for the inconsistency observed many times
between colonies undergoing pesticide poisoning in
the same location. The bees are not all working the
same plants and so some are affected more than
others. Often it is those bees with established flight
patterns located in an area before a pesticide is ap-
plied that are most damaged. Those placed in a field
immediately after application are less affected by
the pesticide because it takes some time for the bees
to scout an area and locate food sources.
Recognizing Bee Kills
Pesticides can affect honey bees in different ways.
Some kill bees on contact in the field; others may
cause brood damage or contaminate pollen, thus kill-
ing house bees. Before dying, poisoned bees can
become irritable (likely to sting), paralyzed or stupi-
fied, appear to be 'chilled' or exhibit other abnormal
behavior. Queens are likely to be superseded when a
colony is being poisoned. Sometimes solitary queens,
banished as if they were somehow "blamed" for
poisoning, may be found near a colony. These symp-
toms are not always distinct and they cannot be
taken as definite signs of pesticide poisoning. Many
chronic management problems such as starvation,
winter kill, chilled brood or disease may result in the
same symptoms. Often these problems may be
caused by pesticides in an indirect manner. So it is
difficult in many instances to categorically state
that bees have been poisoned.
Only one readily recognized symptom is good
evidence of pesticide damage; the presence of many
dead or dying bees near a colony's entrance. In a
short period of time, however, these dead bees may
dry up and the remains be blown away and eaten by
ants or other scavengers. A beekeeper, therefore,
who visits his yards only occasionally may not see
these dead bees and thus not be aware that his colo-
nies have been poisoned.
Reporting Bee Kills
Although it is sometimes difficult to detect
poisoning of bees by pesticides, those cases that are
"clear cut" or "borderline" should be reported. In
the past, there have been few commonly accepted or
uniform reporting procedures for bee kills, and this
lack has contributed to the small amount of good
data on bee kills which the industry can point to in
justifying its concern about such incidents.
At the present time every bee kill can and should
be reported using the pesticide incident report (see
page 15). The form is self-explanatory. The main
rule to follow when filling it out is to be as specific as
possible. Section II is particularly important; there-
fore, include as much as is known, even if nothing
else than a garden spray trade name is available.
Besides sending in the aforementioned form to the
Environmental Protection Agency (EPA), it would
be valuable to send a photocopy or duplicate copy
to: Extension Apiculture, IFAS, University of
Florida, 202 Newell Hall, Gainesville, FL 32611. In
cases where dead and dying bees are observed, a
sample of dying insects (more than a cup if possible)
and a 2 x 2 inch square of comb containing pollen
should be collected and frozen. Indicate on the form
that samples have been taken. Information should
be requested about where and how to send samples
in order to be tested. It is usually suggested that
"uninterested" third parties be asked to actually
take samples of bees suspected of being killed by
pesticides. These persons may include County Ex-
tension Agents, Agriculture Stabilization and Con-
servation Service (ASCS) personnel, State Bee In-
spectors, or other local officials whose role is usually
construed as being more objective in the sampling
Protecting Bees From Pesticides
Most major bee poisoning incidents occur when
plants are in bloom. However, bees can be affected
in other circumstances as well. Keep the following
suggestions in mind when applying pesticides.
Use pesticides only when needed: Foraging
honey bees, other pollinators, and insect predators
are a natural resource and their intrinsic value must
be taken into consideration. Vegetable, fruit, and
seed crop yields in nearby fields can be adversely af-
fected by reducing the population of pollinating in-
sects and beneficial insect predators. It is always a
good idea to check the field to be treated for popula-
tions of both harmful and beneficial insects.
Do not apply pesticides while crops are in bloom:
Insecticide should be applied only while target
plants are in the bud stage or just after the petals
have dropped (Figure 2).
CONTROL SPRAYING TO PREVENT BEE LOSSES.
SPRAY NO SPRAY SPRAY
bud bloom petal fall
< ATTRACTIVE ATTRACTIVE ATTRACTIVE
Figure 2: Control spraying to prevent bee losses.
Apply pesticide when bees are not flying: Bees
fly when the air temperature is above 55-600F and
are most active from 8 a.m. to 5 p.m. Always check a
field for bee activity immediately before application.
Pesticides hazardous to honey bees must be applied
to blooming plants when bees are not working,
preferably in the early evening. Evening application
allows time for these chemicals to partially or total-
ly decompose during the night.
Do not contaminate water: Bees require water to
cool the hive and feed the brood. Never contaminate
standing water with pesticides or drain spray tank
contents onto the ground, creating puddles.
Use less toxic compounds: Some pest control
situations allow the grower-applicator a choice of
compounds to use. Those hazardous to honey bees
must state so on the label. Select other materials or
vary dosages, based on the honey bee mortality
predictor model to be discussed in a later section of
this publication. When in doubt, consult your County
Agricultural Extension Agent for details, recom-
mendations and further information about the tox-
icity of specific compounds to honey bees.
Use less toxic formulations: Not all insecticides
have the same effects when prepared in different for-
mulations. Research and experience indicate:
New microencapsulated insecticides are much
more toxic to honey bees than any formulation
so far developed. Because of their size, these
capsules are carried back to the colony and there
can remain poisonous for long periods. These in-
secticides should never be used if there is any
chance bees might collect the microcapsules.
Always consider using another formulation
Dusts are more hazardous than liquid formula-
Emulsifiable concentrates are less hazardous
than wettable powders.
Ultra-low-volume (ULV) formulations are usual-
ly more hazardous than other liquid formula-
Identify attractive blooms: Before treating a field
with pesticides, it is a good idea to check for the
presence of other blooming plants and weeds which
might attract bees. In many instances bees have
been killed even though the crop being sprayed was
not in bloom. Many times these attractive blooms
can be mowed or otherwise removed, although mow.
ing can result in destroying other beneficial insect
habitat or force destructive insects into the cror
Notify beekeepers: If beekeepers are notified ir
advance of application, colonies can be moved oi
loosely covered with burlap or coarse cloth to con
fine the bees and yet allow them to cluster outside
the hive under the cloth. Repeated sprinkling eaci
hour with water prevents overheating (Figure 3)
Never screen or seal up colonies and do not cove]
with plastic sheeting. This can result in overheating
leading to bee suffocation and death. Florida law re
quires every apiary or bee yard to be plainly market
with the owner's name, address and telephone
The following problem areas concerning applica
tion of pesticides deserve special attention.
Figure 3: Cover colonies with burlap or coarse cloth and keep cover soaked. A tent-like arrangement allows the bees to cluster
outside the hive but inside the tent. Repeated waterings with sprinkler prevents bees from becoming overheated.
Malathion for insect control: The use of malathion
for mosquito and other insect control has some-
times resulted in many dead or weakened bee col-
onies. Losses usually have resulted from:
1. Daytime air applications of ULV malathion at
times when large numbers of bees are flying.
2. Failure to provide adequate warning to bee-
3. Failure to follow a publicized spray schedule.
Although substantial amounts of malathion have
been and are being used around the United States, if
applied and publicized properly, few honey bees are
Carbaryl (Sevin) for insect control: Often
Sevin does not kill field bees immediately, but
allows them time to take contaminated nectar and
pollen back to the colony. Some crops treated with
Sevin under the wrong conditions (i.e., in bloom
using a dust formulation with large numbers of bees
in the field) have been responsible for disastrous
Sevin is one of the nation's most widely used in-
secticides for a wide variety of insect pests. It is also
one of the most toxic to honey bees in certain formu-
lations. There are formulations, however, which are
determined to be less toxic (see tables). Usually,
applicator-beekeeper communication can effectively
be used to adequately protect bees from Sevin
Encapsulated methyl parathion (PennCap M):
By far the most potentially damaging pesticides for
honey bees are those packaged in tiny capsules
(microencapsulated). Microencapsulated methyl
parathion (PennCap M ), for example, is a liquid
formulation containing capsules approximately the
size of pollen grains which contain the active ingre-
dient. When bees are out in the field, these capsules
can become attached electrostatically to the pollen-
collecting hairs of the insects and at times are col-
lected by design. When stored in pollen, the slow-
release feature of the capsules allows the methyl
parathion to be a potential killer for several months.
At the present time, there is no way to detect
whether bees are indeed posioned by microencapsu-
lated methyl parathion, so a beekeeper potentially
could lose replacement bees for those already
poisoned by the pesticide. It is, therefore, strongly
recommended that this formulation be used only
when honey bee exposure is not a possibility.
Other considerations: In general, botanical ma-
terials, dinitro compounds, fungicides and herbi-
cides are relatively nontoxic to honey bees. However,
some of these materials may affect bee development,
and environmental considerations make it man-
datory that all pesticides be used with utmost cau-
tion and only as indicated on the label.
Predicting Honey Bee Mortality
The following description and use of ways to
predict honey bee mortality are extensively adapted
from Leaflet 2883, revised February 1981, Division
of Agricultural Sciences, University of California.
Special thanks is given to E. L. Atkins, D. Kellum
and K. W. Atkins of the University of California at
Riverside for permission to use this material.
Tables 1 and 2 can be used to predict the degree of
toxicity hazard to honey bees in the field when the
pesticide is applied as an early morning spray. In
most instances, the LDso* in micrograms per bee
(ug/bee) can be directly converted to the equivalent
number of pounds of chemical per acre when applied
as a spray to the aerial portions of plants. [For kilo-
grams per hectare (kg/ha), multiply ug/bee by 1.12].
For example, since the LDso of parathion is 0.175
ug/bee, we would expect that 0.17 lb/acre (0.2 kg/ha)
of parathion would kill 50 percent of the bees forag-
ing in the treated field at the time of application or
Generally speaking, some pesticides can be made
safer to honey bees by slightly lowering the dosage.
Conversely, by increasing the dosage only slightly
the pesticide may become highly hazardous to bees.
This information is particularly useful when the
LDo0 in micrograms per bee is approximately equal
to the normal dosage in pounds per acre needed in
the field to control pest populations. For example,
consider a pesticide, which is normally applied at
dosages of 0.5 to 1.5 lb/acre, having an LD50o of 1.0
ug/bee. Furthermore, suppose that the pesticide has
a slope value of 4.0 probits. Then, if this chemical is
applied at 0.5 lb/acre, we would expect a 12 percent
kill of bees; at 1 lb/acre, we would expect a 50 per-
cent kill; and, at 1.5 lb/acre, we would expect a 72
Table 3 shows additional examples of anticipated
bee mortalities at other selected slope values with
increasing and decreasing dosages of a pesticide hav-
ing an LD0so value of 1.0 ug/bee. Any pesticide hav-
ing a known LDo0 value can be similarly read by
substituting the LDso (the 1.0 or center column) of
Table 3 and multiplying the LD5o value by the other
factors (0.1, 0.25, 0.5, 0.75, 1.25, 1.5, 3.0, and 10.0) to
obtain the proper range of dosages in pounds per
acre. By using the value closest to the known slope
value for the particular pesticide, the percent mor-
talities for that chemical can be predicted.
It is emphasized that the method described is a
rule-of-thumb, and that some pesticides are more or
less hazardous than one can anticipate from the
laboratory data. Most of these are pesticides which
have very short or very long residual characteristics.
The Honey Bee Mortality Predictor
A Rapid Method
The nomogram (Figure 4) provides a quicker
method of predicting the mortality of honey bees
from field applications of pesticides than the one
just discussed (Table 3), which requires mathe-
matical calculations. The method is also useful for
predicting potential hazards to honey bees when ap-
plying pesticides for mosquito abatement and for
pest control in forest, rangeland, recreational areas,
and home gardens.
An example of how the Predictor works: Let us
say that parathion has an LDso of 0.175 ug/bee;
slope value of 4.96 probits. We intend to apply
parathion at the rate of 0.25 lb/acre a.i. (active ingre-
dient) to control pest populations of insects in an
area which contains colonies of honey bees for polli-
nating the crop. How hazardous will this dosage be
to the bee colonies if they cannot be protected dur-
ing application or removed to safety?
Read the instructions given with the Predictor.
Note that an LD5o of 0.175 ug/bee is equivalent to
0.175 lb/acre a.i. and that 0.175 appears in the LD5o
or x 1" column in the dosage table. You want to
apply 0.25 lb/ acre; in the dosage table this dosage
appears under the "1.5 times the LDo0" column. The
1.5 indicates that 0.25 lb/acre is 1.5 x the LDso rate
of 0.175 lb/acre. Place a straightedge even with the
"1.5 dosage increase" level on the left vertical scale.
Since the slope value is 4.97 probits (approximately
5 probits) rotate the straightedge through the
5-probit point of the "slope value" guide line. The
straightedge now will intersect the right vertical
scale, which is the "predict percent mortality of
honey bees in the field". You will note that the
straightedge intersects the mortality scale at 78 per-
cent. Therefore, the application of 0.25 lb/acre of
parathion is predicted to kill approximately 78 per-
cent of the bees that contact the treated foliage or
that are flying through the treated area during the
application of the spray.
Remember that bee mortality would be reduced
approximately 50 percent (to 39 percent in the ex-
ample) if the parathion application was made during
*LDs is the experimental dosage at which 50% of a test bee
the night (from darkness to 4 a.m.), and that bee
mortality would be increased approximately two
times if the parathion application was made after 7
a.m. and later into the day (more than 98 percent in
the example). Also notice that by reducing the
dosage only slightly to .22 lb/acre, the mortality is
reduced from 78 percent to 65 percent.
Cooperation and Communication
Keys to Bee Protection
In order to adequately protect honey bees from
pesticides, there must be a good deal of cooperation
between applicators, growers, beekeepers, extension
workers and government officials. The key to this
cooperation is constant communication fostered by
trust on the part of all involved.
It should be realized that protecting honey bees
from pesticides is often extremely difficult in spite
of the fact that most of these chemicals are not con-
sidered hazardous to bees. There are many variables
which must be pondered in the decision-making pro-
cess leading to pesticide use. If those which con-
tribute to honey bee safety are given due considera-
tion, application of pesticides and protection of
honey bees are not mutually exclusive. Generally it
is only when decisions are based on insufficient in-
formation and/or made without regard to the safety
of honey bees that they result in damaging bee
The purpose of this publication is to provide the
necessary information to consider when contem-
plating use of pesticides and the potential effects on
honey bees. If it contributes to saving even one bee,
which can then expend energy in the service of pol-
lination to agriculture, this effort will not have been
Table 1-Relative Toxicity of Pesticides to Honey Bees Determined by Laboratory and
Field Tests (California, 1950 through 1980.)
(Number keyed notes on their uses can be found at bottom of table)
Group I-highly toxic: Severe losses may be expected if used when bees are present at treatment time or
within a day thereafter, except where noted to the contrary.
Pesticide (trade name and/or common name)
aldrin2 Dursban 2, chlorpyrifos Nemacur fenamiphos
Ambush2.18, permethrin Ekamet, etrimfos Nudrin2, methomyl
arsenicals 1,2 EPN1,2 Orthene2, acephate
Avermectin17 Ethyl Guthion, azinphos-ethyl parathion1.2
Azodrin1.2, monocrotophos Famophos, famphur Pay-Off
Baygon2, propoxur Ficam, bendiocarb Phosdrin1.2,3, mevinphos
Baytex2, fenthion Folithion, fenitrothion phosphamidon2, Dimecron
Bidrin1.2, dicrotophos Furadan2.5, carbofuran Pounce 218, permethrin
Bux, bufencarb Gardona@ 2, stirofos Pydrin2, fenvalerate
carbosulfan2, FMC-35001 Guthion @12, azinphos-methyl resmethrin, Synthrin
Cygon 2, dimethoate heptachlor'12 Sevin2, carbaryl
Cythion 24, malathion Imidan2, phosmet Spectracide2, diazinon
Dasanit5, fensulfothion Lannate2, methomyl Sumithion, fenitrothion
DDVP2, dichlorvos Lorsban, chlorpyrifos Sumithrin, d-phenothrin
Dibrom@ 2.3, naled malathion2A4 Supracide 2, methidathion
Decis 2, decamethrin Matacil, aminocarb Tamaron 2, methamidophos
De-Fend@2, dimethoate Mesurole, methiocarb Temik184.108.40.206, aldicarb
diazinon2, Spectracide methyl parathion1.2111,12 tepp1.2.3
dieldrin1.2 Monitor2, methamidophos Vapona 2, dichlorvos
Dimecron 2, phosphamidon
Group II-moderately toxic: Can be used around bees if dosage, timing, and method of application are
correct, but should not be applied directly on bees in the field or at the colonies.
Insecticide (trade name andlor common name)
Abate2, temephos DDT1.2.10 Pyramat
Agritox, trichloronate Di-Syston1.2,6.18, disulfoton Sevin 4-Oil2, carbaryl
Bolstar, sulprophos Dyfonate, fonofos Sevimol2, carbaryl
Carzol2, formetanate hydrochloride endrin1.2 Systox1,2.18, demeton
chlordane2 Korlan, ronnel Thimet@'1.26, phorate
Ciodrin, crotoxyphos Larvin 2, thiodicarb Thiodan 2, endosulfan
Counter@, terbufos Metasystox-R2, oxydemeton-methyl Trithion2, carbophenothion
Croneton, ethiofencarb Mocap, ethoprop Vydate2, oxamyl
Curacron, profenofos Perthane, ethylan Zolone, phosalone
Group Ill-relatively nontoxic: Can be used around bees with minimum injury.
Insecticides and Acaracides (trade name and/or common name)
Bacillus thuringiensis17, Bactur,
copper oxychloride sulfate
cupric hydroxide, Kocide
Fundal, chlordimeform pyrethrum (natural)
Galecron, chlordimeform rotenone2
Heliothis polyhedrosis virus sabadilla2
Kelthane1, dicofol Sayfos, menazon
Mavrik2, fluvalinate Sevin SL2, carbaryl
methoxychlor2, Marlate Sevin XLR2, carbaryl
Mitac, amitraz Smite, sodium azide
Morestan, oxythioquinox Tedion, tetradifon
Morocide, binapacryl Tetram
Murvesco, fenson Tokuthion, prothiophos
nicotine2 Torak, dialifor
Omite, propargite toxaphene1'2
Pentac, dienochlor Zardex, cycloprate
Fungicides (trade andlor common name)
Dessin, dinobuton Morestan, oxythioquinox
Difolatan, captafol Morocide, binapacryl
Dithane D-14, nabam Mylone, dazomet
Dithane M-22, maneb Phaltan, folpet
Dithane M-45, manzeb Plantvax, oxycarboxin
Dithane Z-78, zineb Polyram, metiram
Du-Ter, fentin hydroxide Ridomil
Dyrene, anilazine Sisthane, fenapanil
ferbam Smite, sodium azide
Hinosan, edifenphos thiram, Thylate
Indar, butrizol thyfural
Karathane, dinocap Vitavax, carboxin
Lesan, fenaminosulf ziram, Zerlate
Herbicides, Defoliants, and Desiccants (trade andlor common name)
Amex 820, butralin
Aquathol K, endothall, dipotassium
endothall, sodium salt, Accelerate
Eradicane, EPTC + safener
Hydrothol 191, endothall
Smite, sodium azide
Sutan +, butylate
Chloro IPC, chlorpropham
Desiccant L-10'.9, arsenic acid
Turf Herbicide, endothall, disodium
Nematicides and Miscellaneous (trade andlor common name)
Smite5, sodium azide
7 "I-1 f-i1 11 WM %tLLIr 131
Number-keyed Notes on Pesticide Uses
1. Florida state regulations require permits for most
uses of these chemicals.
2. Laboratory- and field-tested mainly on alfalfa, citrus,
cotton, ladino clover, milo and sweet corn; all other
chemicals were laboratory-tested only.
.3. Dibrom, Phosdrin and tepp have such short
residual activity that they kill only bees contacted at
treatment time or shortly thereafter. Usually safe to
use when bees are not in flight; not safe to use
4. Malathion has been applied on thousands of acres of
alfalfa in bloom without serious loss of bees.
However,- occasional heavy losses have occurred,
particularly under high temperature conditions. If ap-
plied to alfalfa in bloom, it should be only as a spray,
and application should be made during the night or
early in the morning when bees are not foraging in
the field. Undiluted technical malathion spray (ULV)
should not be used around bees.
6. Di-Syston@ (disulfoton) and other systemic pesti-
cides used as seed treatments have not caused bee
7. Temik (aldicarb), although highly toxic to bees as a
contact poison, is used only in granular form, and ex-
tensive field usage has not caused bee losses.
10. DDT has been withdrawn for most uses in the U.S.A.
11. Field dosages have caused brood damage.
12. The microencapsulated formulation of methyl para-
thion, known as Penncap-M is highly toxic to
foraging bees, young hive bees, and brood. Overall, it
is 13 times more hazardous to honey bees than the
EC (emulsifiable concentrate) formulation. Penncap-
M is too hazardous to be applied to any area at any
time when bees are present in the field or within one
mile of the area to be treated.
13. Plant growth regulator.
15. Nitrification inhibitor.
16. Chemical ripener.
17. Insect growth regulator.
18. Honey bee repellent.
Table 2-Data for Use of Honey Bee Mortality Predictor (see Figure 5)
Bee hazard and residual toxicity information is based on field tests (1950-1980) for dosages normally recommended
and utilized as dilute sprays in water on agricultural crops for controlling pest insects and mites. This information is
usually applicable for mosquito abatement, forest, rangeland, recreational, and residential treatments but not for low-
volume, no-water sprays (ULV).
Night applications (darkness until 4 A.M.) will reduce bee kill approximately 50% and reduce overall bee hazard at least
one category from sprays applied as early morning applications (daylight to 7 A.M.): applications made after 7 A.M. will
increase the overall bee hazard approximately two times, raising the hazard to at least the next higher category.
Group I-highly toxic pesticides (LD5o = 0.001 to 1.99 ug/bee): Severe losses may be expected if these
pesticides are applied when bees are present at treatment time or within a day thereafter, except as in-
dicated by footnotes. (Listed in order of toxicity: first named is most toxic.)
Field test data:
Laboratory data Toxicity of
Pesticide* Slope, residues to best
(trade and/or common name) probits LD50 No. days Hazard
tepp .3 0.68 0.002 0.5(H) ML
bioethanomethrin 3.95 0.035 0.5(H) L
resmethrin 4.17 0.062 -
decamethrin, Decis 4.88 0.067 1.5(H) NIL
Pay-Off 3.37 0.078 0.5(M) NIL
chlorpyrifos, Lorsban, Dursban 10.17 0.110 2-3.5(H) M-MH
methyl parathion't 5.13 0.111 0.5(H) H-VHt
dieldrin' 2.51 0.133 1.5-5(H) H
carbofuran5, Furadan 6.14 0.149 3>5(H) M-H
permethrin'8, Ambush, Pounce 5.52 0.159 >5(VH) L
parathion' 4.96 0.175 1(H) H-VH
fenitrothion, Sumithion 5.75 0.176 -
dimethoate', Cygon, De-Fend 5.84 0.191 1-3.5(H) M-VH
methidathion', Supracide 8.48 0.237 2.5(H) MH
EPN1 4.31 0.237 1.5-3(H) H
methyl parathion't, encapsulated, Penncap-M 5.13 0.241 >5(H) H-VHt
etrimfos, Ekamet 2.52 0.264 -
aldicarb.5.7, Temik 5.00 0.272 NIL NIL
mexacarbate, Zectran 4.87 0.302 3(H) H
dicrotophos', Bidrin 15.86 0.305 2-4(H) M-MH
mevinphos'13, Phosdrin 7.77 0.305 <1-1.5(H) M-H
fenthion, Baytex 6.14 0.319 -
fensulfothion5, Dasanit 4.78 0.337 -
aldrin 5.06 0.352 -
monocrotophos', Azodrin 8.31 0.357 2-3.5(H) MH-VH
diazinon, Spectracide 8.03 0.372 1-2(H) H
methiocarb, Mesurol 3.35 0.372 -
fenvalerate, Pydrin 4.46 0.408 1(L) NIL
famphur, Famophos 4.85 0.414 -
azinphos-methyl', Guthion 7.43 0.428 5(H) M-VH
bendiocarb, Ficam 3.28 0.428 -
naled3, Dibrom 16.43 0.485 <1-1.5(H) MH-VH
dichlorvos, DDVP, Vapona 8.61 0.501 -
heptachlor', Drinox 5.94 0.526 -
isofenphos, Amaze, Oftanol 6.61 0.606 -
carbosulfan, FMC-35001 4.69 0.678 3.5(H) ML
malathion4, Cythion 7.83 0.726 1-2(M) L-MH
azinphos-ethyl, Ethyl Guthion 7.92 0.958 -
aminocarb, Matacil 3.61 1.12 -
phosmet, Imidan 3.55 1.13 3.5(H) MH-VH
methomyl5, Lannate, Nudrin
Group II-moderately toxic pesticides (LD5o= 2.0 to 10.99 /g/bee): These can be used in the vicinity of
bees if dosage, timing, the method of application are correct, but should not be applied directly on bees in
the field or at colonies. (Listed in order of toxicity to honey bees; first named is most toxic).
Field test data:
Laboratory data Toxicity of
Pesticide* Slope, residues to beest
(trade and/or common name) probits LD50 No. days Hazard
temephos, Abate 2.56 1.40 0-3(M) L
demeton''8, Systox 10.02 1.71 1(L) L
trichloronate, Agritox 4.28 2.00 -
endrin1, Endrex 4.06 2.04 1-3(M) L-M
crotoxyphos, Ciodrin 15.42 2.31 -
Pyramat 5.08 2.62 -
oxydemeton-methyl, Metasystox-P 2.49 2.86 0.5(L) M-H
profenofos, Curacon 5.96 3.46 -
terbufos, Counter 3.54 4.09 -
ethylan, Perthane 4.01 4.57 -
ethoprop, Mocap 4.66 5.56 -
ronnel, Korlan 2.11 5.62 -
disulfoton1-6-18, Di-Syston 1.19 6.12 1(L) NIL
DDT1'10 4.74 6.19 1(L) L
ethiofencarb, Croneton 1.99 6.85 NIL NIL
Larvin, thiodicarb 3.52 7.08 NIL ML
sulprofos, Bolstar 5.53 7.22 -
endosulfan, Thiodan 3.15 7.81 2(L) L-MH
fonofos, Dyfonate 4.87 8.68 -
chlordane 2.34 8.80 -
phosalone, Zolone 3.67 8.97 -
formetanate hydrochloride, Carzo 4.21 9.21 2(L) L
phoratel6, Thimet 1.27 10.25 <1-1(L) L
oxamyl, Vydate 5.81 10.26 3-4(H) VH
carbophenothion, Trithion 2.78 12.99 <1(M) L
Sevin SL, carbaryl 1.57 13.72 6(MH) H
Primor@, pirimicarb 2.87 18.72 0.5(L) L
Sevin SLR, carbaryl 1.14 26.53 >6(H) M
Mavrik, fluvalinate 1.85 65.85 0.5(L) L-ML
Source: Toxicity of Pesticides to Honey Bees, Leaflet 2286, and Toxicity of Pesticides and Other Agricultural Chemi-
cals to Honey Bees, Leaflet 2287. (University of California Agricultural Sciences publications).
* See Table 1 for key to numbers 1-18.
t Toxicity of residue to honey bees: No. days = average time in days that residue is toxic to bees; Hazard = severity of
the honey bee hazard (L= low; M = moderate, H = high, ML= moderately low, MH = moderately high, VH = very high.
NIL= no toxicity and/or no hazard,- = no verified information available). NOTE: Night application (darkness until
4 A.M.) will reduce bee kill at least 50% and reduce bee hazard at least one category from sprays applied as early
morning treatments (daylight to 7 A.M.); applications made after 7 A.M. will increase overall bee hazard approxi-
mately two times, raising the hazard to at least the next higher category.
t The encapsulated methyl parathion formulation, Penncap-M, is highly toxic to foraging bees, young hive bees, and
brood. Overall, it is 13 times more toxic to honey bee colonies than the EC formulation (emulsifiable concentrate).
Penncap-M is too hazardous to be applied to any area at any time when bees are present in the field or within 1
mile of the area to be treated.
Used only as soil application and/or-as granules.
When used as soil application of granules: No. days toxic, NIL; Hazard, NIL.
Table 3-Examples of Anticipated Honey Bee Mortality When a Pesticide With a LD50 Value of
1.0 is Applied at Selected Slope Values and Increasing and Decreasing Dosages
Slope value Percent mortality at following dosage (Iblacre):
0.1 0.25 0.5 0.75 1.0 1.25 1.5 1.75 3.0 10.0
Below LDs0 LDs0 Above LDs0
2 3 12 28 42 50 57 64 68 82 97
4 1 12 32 50 66 72 82 96 -
6 2 17 50 76 91 97 -
16 3 50 93 -
Predicted bee mortality (percent)
value for pesticides
Position of straightedge
for example using:
-*......22 Ib./acre parathion
-----.25 lb./acre parathion
HONEY BEE MORTALITY PREDICTOR
Instructions for Figure 4
A. Look up the LDso0 in Table 2 for the pesticide you are going to use. Find this value, or the value closest
to it in Section 1 below.
B. Read to the right on the same line into Section 2 and find the dosage, or the closest dosage to the one
you intend to actually use in the field.
C. From the actual dosage (Section 2), read down the column into Section 3. This figure represents how
much more or less than the LDso your actual dosage is. Find this figure on vertical line of left side of
the Predictor (Figure 4).
D. Look up the Slope Value in Table 2 for the pesticide you are going to use, and locate it on the Slope
Value line on Figure 4.
E. Use a ruler or other straightedge to connect the point on the Dosage Factor line to the point on the
Slope Value line in Figure 4. Extend the straightedge to intersect the vertical line on the right in the
Predictor. At the point of intersection, you can read the predicted percent mortality of honey bees in
the field for the type and dosage of pesticide you intend to use.
NOTE: By rotating your straightedge and working backwards, you can determine how much to lower the
dosage to avoid serious bee kill.
7 6 5 4
LDso of pesticide Section 2.
(Ib/acre-a.i.) Actual dosage you intend to use in pounds of active ingredient (a.i.) per acre
0.175 0.04 0.09 0.13 0.175 0.22 0.26 0.31 0.35
0.30 0.08 0.15 0.23 0.30 0.38 0.45 0.53 0.60
0.40 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80
0.50 0.13 0.25 0.38 0.50 0.63 0.75 0.88 1.0
0.70 0.18 0.35 0.53 0.70 0.88 1.00 1.23 1.4
1.00 0.25 0.5 0.75 1.00 1.25 1.50 1.75 2.0
1.25 0.31 0.63 0.94 1.25 1.56 1.88 2.19 2.5
1.50 0.38 0.75 1.13 1.50 1.88 2.25 2.63 3.0
2.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
2.5 0.63 1.25 1.88 2.5 3.13 3.8 4.4 5.0
3.0 0.75 1.5 2.25 3.0 3.75 4.5 5.25 6.0
4.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
5.0 1.25 2.5 3.8 5.0 6.3 7.5 8.8 10.0
6.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0
7.5 1.9 3.8 5.6 7.5 9.4 11.0 13.0 15.0
10.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0
Factor representing how much more or less than the LDso you intend to use
0.25x 0.5x 0.75x 1.0x 1.25x 1.5x 1.75x 2.0x
Anderson, L. D., and E. L. Atkins. 1966. 1965 Research on the effect of pesticides on honey bees. Amer. Bee
Jour. 106 (6): 206-08.
1968. Pesticides in relation to beekeeping. Ann. Rev. of Ent. 13: 213-38.
Anderson, L. D., E. L. Atkins, F. E. Todd and M. D. Levin. 1968. Research on the effect of pesticides on honey
bees. Amer. Bee Jour. 108 (7): 277-79.
Atkins, E. L. 1972. Rice field mosquito control studies with low volume Dursban sprays in Colusa County,
California. V. Effects upon honey bees. Mosquito News 32 (4): 538-41.
Atkins, E. L. 1975. Injury to bees by poisoning. In: The Hive and the Honey Bee, Rev. Ed. Hamilton, IL:
Dadant & Sons. 740 pp. (see esp. p. 683, table 3).
Atkins, E. L., and L. D. Anderson. 1976. Honey bee visitation patterns on some agricultural crops and their
utilization in timing pesticidal applications. Univ. Calif. Coop. Ext., From: The U.C. Apiaries, May-June,
Atkins, E. L., L. D. Anderson, and E. A. Greywood. 1970. Research on the effect of pesticides on honey bees
1968-69. Part I. Amer. Bee Jour. 110 (10): 387-9; Part II. Amer. Bee Jour. 110 (11): 426-92.
Atkins, E. L., L. D. Anderson, and F. Todd. 1970. Honey bee field research aided by Todd dead bee hive
entrance trap. Calif. Agric. 24(10): 12-13.
Atkins, E. L., E. A. Greywood, and R. L. Macdonald. 1973. Toxicity of pesticides and other agricultural
chemicals on honey bees. Univ. Calif. Div. Agric. Sci. Leaf. 2287.
Atkins, E. L., D. Kellum, and K. W. Atkins. 1978. Encapsulated methyl parathion formulation is highly
hazardous to honey bees. Amer. Bee Jour. 118 (7): 483-85.
1978. Integrated pest management strategies for protecting honey bees from pesticides. Amer. Bee
Jour. 118 (8): 542-3; 547-48.
Atkins, E. L., D. Kellum, and K. J. Neuman. 1975. Toxicity of pesticides to honey bees. Univ. Calif., Div.
Agric. Sci. Leaf. 2286.
Atkins, E. L., R. L. MacDonald, and E. A. Greywood-Hale. 1975. Repellent additives to reduce pesticide
hazards to honey bees: Field tests. Environ. Ent. 4 (2): 207-10.
Atkins, E. L., R. L. MacDonald, T. P. McGovern, M. Berosa and E. A. Greywood-Hale. 1975. Repellent
additives to reduce pesticide hazards to honey-bees: Laboratory tests. Jour. Apic. Res. 14 (2): 85-97.
Gary, N. E. 1967. A method of evaluating honey bee flight activity at the hive entrance. Jour. Econ. Ent. 60
Johansen, C. A., M. D. Levin, J. D. Eves, W. R. Forsyth, H. B. Busdicker, D. S. Jackson, and L. I. Butler.
1965. Bee poisoning hazard of undiluted malathion applied to alfalfa in bloom. Wash. Agric. Exp. Stn., Cir.
Womeldorf, D. J., E. L. Atkins, and P. A. Gillies. 1974. Honey bee hazards associated with some mosquito
abatement aerial spray applications. Calif. Vector News 21 (9): 51-55.
U.S. ENVIRONMENTAL PROTECTION AGENCY
PESTICIDE INCIDENT REPORT
This report is authorized by law(7 U.S.C. 135). Although you are not required to respond, your cooperation will help assure that our inform-
ation is comprehensive, accurate, and timely. Use Section X on the reverse for a brief description of the circumstances leading to the
incident and for additional comments. Please read the instructions before completing this report.
SECTION I IDENTIFICATION
DATE OF INCIDENT DATE OF REPORT
AUUKbESS (street, city, state, and ZIP code)
LOCATION OF INCIDENT (city, county, and state)
SECTION II PESTICIDE DESCRIPTION
PRODUCT TRADE NAME EPA REGISTRATION NUMBER
IF MORE THAN ONE
CHECK HERE WAND ACTIVE INGREDIENTS
LIST ON BACK.
TYPE OF PESTICIDE FORMULATION OF PESTICIDE
INSECTICIDE UNKNOWN BAIT EMULSIFIABLE CONCENTRATE
HERBICIDE OTHER (specify): DUST TECHNICAL GRADE
FUNGICIDEi GRANULATED AEROSOL
RODENTICIDE WETTABLE POWDER UNKNOWN
DISINFECTANT ___|_ ____ LIQUID OTHER (specify):
SECTION III HOW EXPOSED SECTION IV CIRCUMSTANCE SECTION V-LOCATION
ACCIDENTAL INGESTION HOUSEHOLD USE HOME OR YARD AREA
ACCIDENTAL SPILL FORMULATION, MIXING, OR LOADING AGRICULTURALLY RELATED AREA
SPRAY DRIFT APPLICATION: GROUND(1); AERIAL(2) INDUSTRIALLY RELATED AREA
EQUIPMENT FAILURE/MAINTENANCE FIELD REENTRY BUILDING: OFFICE, SCHOOL, ETC.
_SUICIDE OR HOMICIDE ATTEMPT DISPOSAL(1); TRANSPORTATION(2) POND, LAKE, STREAM OR RELATED AREA
UNKNOWN FIRE(1); FLOOD(2); OTHER DISASTER(3) NURSERY OR GREENHOUSE
OTHER (specify): UNKNOWN UNKNOWN
S_ OT HER (specify): OTHER (specify):
SECTION VI HUMANS) EXPOSED
OUTCOME MAJOR SYMPTOMS ROUTE OF o 0 '-
./EXPOSURE / 4~ /
% 9 O / O "/O 1 / 11 /' ^o OCCUPATION (specify):0,4I 0(
:::_:_:::::_:SECTION VII -O ANIMALS) EXPOSED ,
TYPE: LIVESTOCK POULTRY WILDLIFE BIRDS FISH PETS BEES THER (specify):
:0 .i 4,OA. o0. i: A A
COMMON NAMES) NO. EXPOSED NO. AFFECTENO. TREATED NO. FATALITIES WERE LAB TESTS DONE?
OES NO |UNKNOWN
SECTION VIII PLANTS EXPOSED
|'LAWN FLOWERS TREES | o COMMERCIAL TURF,- ,SHRUBS, -THER(specify): UPAT
A4, ,_':4 0 _' _"__ _______YES -NO UNKNOWN__UPA_'
SECTSECTION IX M EDIUM OR OBJECT CONTAMINATEDSED
TYPATER FOLIVESTOCK POUEHICLE BUILDING SOIL FISH PETS BEES THEIR (specify):
[-'-]YES L---NO [::]UNKNOWN
PRIMARY ROUTE OF EXPOSURE LIST MAJOR SYMPTOMS
3jORAL EZIDERMAL [:]IINHALATION -IIUNKNOWN
SECTION VIII PLANTS EXPOSED
TYPE:--IZCROP IZORCHARD -IIIFORESTS I--]NURSERY/GREENHOUSE Z--IPASTURE/RANGE LI--HOME VEGETABLE GARDEN
EZ]LAWN -IFLOWERS [::]TREES [-]COMMERCIAL TURF ZjSHRUBS --OTHER (specify):
COMMON NAME(S) WERE LAB TESTS DONE? AMOUNT OF PLANTS (number, acres, 20 foot rows, bushels, etc,).
DYES :INO LI]UNKNOWN
EPA Form 8550-5 (Rev. 2-79) REPLACES PREVIOUS EDITIONS OF EPA FORMS 8550-4, 5
Complete the above form and mail to: U. S. Environmental Protection Agency; c/o PIMS Research Center;
Division of Biostatistics, UMSM, R-30; Post Office Box 016960; Miami, Florida 33101
KI A = n= 0=0norco A C er F~e- I A -r I^ Ll /A~r
-- 1 r Iti
CVIV -hl le
NAM Ur -U1IF-
This publication was promulgated at a cost of $2074.00, or 30.5 cents per copy for the purpose of inform-
ing beekeepers and the general public about pesticides and honey bees. 2-6.8M-83
COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL
SCIENCES, K. R. Tefertiller, director, In cooperation with the United States Department of Agriculture, publishes this Infor-
mation to further the purpose of the May 8 and June 30, 1914 Acts of Congress; and is authorized to provide research, educa-
tional information and other services only to individuals and institutions that function without regard to race, color, sex or
national origin. Single copies of Extension publications (excluding 4-H and Youth publications) are available free to Florida
residents from County Extension Offices. Information on bulk rates or copies for out-of-state purchasers is available from
C. M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida 32611. Before publicizing this
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