Protecting Honey Bees from Pesticides
HYG-2161-97
Dr. James E. Tew
E-mail: Tew.1@osu.edu
Apiculture
Pesticide Problems
Honey bees and other insect pollinators play an important role
in the production of many crops in Ohio. However, since most crops
must be protected from insect pests and diseases, pesticide poisoning
is the most serious problem for pollinating insects in agricultural
areas. Protecting pollinators, especially honey bees, from pesticide
poisoning should be part of any pesticide program. The following
recommendations can help minimize bee kills.
Pesticides on Blossoms. The blossom is usually the only part
of a plant that bees visit. To avoid killing bees, do not apply
pesticides hazardous to bees during the blooming period. When
the treated area contains the only attractive plants, in bloom
within flight range, injury may occur to colonies several miles
away. Treating non-blooming crops with a hazardous pesticide when
cover crops, weeds, or wild flowers are in bloom within (or near)
the treated field may also cause heavy bee losses.
Drift of Pesticides. Drift occurs from nearly all spray or
dust applications of pesticides from a short distance to miles
downwind. Pesticide dusts drift farther than sprays. Pesticides
applied by plane usually drift farther than those applied by ground
equipment. Generally, it is less hazardous to apply pesticides
near apiaries with ground equipment than by plane. Drift can be
reduced by applying pesticides in the evening or early morning
when the air is calm.
Time of Application. Ideally, pesticides should be applied
when there is no wind and when bees are not visiting plants in
the area. The time and intensity of bee visitation to a given
crop depends on the abundance and attractiveness of the bloom.
For example, apple trees or clover in bloom may be attractive
to bees all day while cucumbers and corn are usually attractive
in the morning and early afternoon hours. In general, evening
or early night applications are the least harmful to bees.
Formulation of Pesticides. Dusts are usually more hazardous
to bees than sprays. Wettable powders often have a longer residual
effect than emulsifiable concentrates. Granular pesticides seem
to present very little hazard. Ultra-low volume (ULV) formulations
of some pesticides are much more toxic than regular sprays. No
effective repellent has been developed that can be added to pesticides
to keep bees from treated areas.
Toxicity of Pesticides. Most agricultural pesticides have been
tested for their toxicity to honey bees. However, laboratory and
field results do not always coincide, due to peculiarities of
bee behavior, length of residual life of the pesticide, or the
effects of different formulations.
Insecticides affect bees in one or more ways: as stomach poisons,
as contact poisons, and as fumigants. Pyrethroids, organophosphates,
and carbamates vary in their toxicity to bees from relatively
nonhazardous to very hazardous, depending upon the individual
material or combination of materials. Some bacteria, protozoans,
and viruses that are currently recommended for biological control
pose a serious hazard to bees.
Herbicides, defoliants, and desiccants such as paraquat, MAA,
and MSMA reportedly were extremely toxic when fed to newly emerged
worker honey bees or when sprayed onto older bees in field tests.
Most tests have shown other materials in this class to be nonhazardous
to bees, except that they kill or damage nectar- or pollen-producing
plants.
Fungicides seem to cause little trouble for bees. Captan at
field dosages has caused brood damage.
Sex Lures, Attractants, and other Hormones usually cause no
problem for bees. Occasionally, a few honey bees and bumblebees
have been found in traps containing Japanese beetle lures.
Precautions for Farmers and Applicators
- Apply pesticides only when needed.
- Use the recommended pesticide at the lowest effective rate.
- Use the pesticide least hazardous to bees that will control
the pest involved. If all recommended pesticides are equally
hazardous to bees, use the one that has the shortest residual
effect.
- Use sprays or granules instead of dusts.
- Use ground equipment instead of aerial application to apply
pesticides near bee hives.
- Apply pesticides in late afternoon or at night when bees
are not working the blooms.
- Avoid drift of pesticides onto plants that are attractive
to bees.
- Notify beekeepers several days before applying any pesticide
that is hazardous to honey bees. This will give them a chance
to protect their colonies. However, notifications are not a release
of responsibility.
Precautions for Beekeepers
- Place colonies where they will be away from fields that are
routinely treated with hazardous pesticides and will not be subjected
to pesticide drifts.
- Identify your apiary. Post your name, address, and phone
number in a conspicuous place near your apiary. Let farmers and
custom applicators in your area know where your apiaries are
located so they will not unknowingly poison them.
- Be familiar with pesticides commonly used in your area and
what their application dates are.
- Relocate colonies that are exposed repeatedly to hazardous
pesticides. Also, remember that soon after colonies are moved
to a new location, foraging bees search for water. They may collect
water that has been contaminated with pesticides. To reduce the
chance of bee losses, provide clean water near the hives.
Bee Kill Estimations |
0 - 100 dead bees per day |
Normal Die-off |
200 - 400 dead bees per day |
Low Kill |
500 - 900 dead bees per day |
Moderate Kill |
1000 or more dead bees per day |
High Kill |
The Insecticide Container Label
Though not a long document, the insecticide label represents
vast amounts of research, legal regulations, and instructions.
There are thousands of registered pesticide formulations. Each
label clearly gives a brand name in bold letters across the label
while the common name and chemical ingredients follow in the section
called "Active Ingredients." For example, the Chevron
Chemical Company manufactures Orthenex (brand name). In the "Active
Ingredients" section of the label, the name acephate (common
name), is followed by the chemical name.
The following partial list of pesticides represents groups
of materials ranked by toxicity to honey bees and is presented
for general information only. Toxicity ranking may vary depending
on the formulation of a pesticide. For specific information on
the effects of a specific pesticide on honey bees, contact your
county Extension office.
Pesticides Grouped According To Their Relative Degree of Hazard
to Honey Bees (Common name first, followed by a brand name example)
Group 1. Hazardous: Generally, these materials kill bees on
contact during application and for one or more days after application.
Highly toxic
- 2,4-D (Weed-B-Gone*)
- abamectin (Zephyr*)
- acephate (Orthene*)
- azinphos-methyl (Guthion*)
- bifenthrin (Capture*)
- carbaryl (Sevin*)
- carbosulfan (Advantage*)
- chlormephos (Dotan*)
- chlorpyrifos (Lorsban*, Dursban*)
- cyfluthrin (Baythroid*)
- d-phenothrin (Sumithrin*)
- demeton-s-methyl (Metasystox (i)* (50-% Premix))
- diazinon (Spectracide*)
- dichlorvos (DDVP)
- dicrotophos (Bibrin*)
- dimethoate (Cygon*, De-Fend*)
- esfenvalerate (Asana* XL)
- ethion (tech) (Ethanox*)
- etrimfos (Ekamet*)
- fenitrothion (Sumithion*)
- fenpropathrin (Farmatox*)
- fensulfothion (Dasanit*)
- fenthion (Baytex*)
- fenvalerate (DMSO) (Belmark*)
- flucythrinate (Pay-Off*)
- fonofos (Dyfonate*)
- heptachlor (Fennotox*)
- lindane (Lindane)
- malathion (Malathion 50*, Malathion ULV)
- methamidophos (Monitor*, Tamaron*)
- methidathion (Supracide*)
- methiocarb (Mesurol*)
- methyl parathion (Penncap-M*)
- mevinphos (tech) (Phosdrin*)
- monocrotophos (Azodrin*)
- naled (Dibrom*)
- omethoate (Folimat*)
- oxydemethon-methyl (Metasystox-R*)
- oxydisulfoton (Disyston S*)
- parathion (Bladan*)
- permethrin (Ambush*, Pounce*)
- phosmet (Imidan*)
- phosphamidon (Dimecron*)
- propoxur (Baygon*)
- pyrazophos (Afugan*)
- resmethrin (Chrysron*)
- tetrachlorvinphos (Gardona*)
- tralomethrin (Scout X-TRA*)
Group II. Moderately Hazardous: These materials can be used
with limited damage to bees if not applied on bees in the field
or on hives near the field. Correct application rate, timing,
and method of application, are factors that can reduce pesticide
kills.
Moderately Toxic
- Acetochlor (Acenit*)
- Aclonifen (Challenge*)
- allethrin (Pynamin*)
- alphacypermethrin (Fastac*)
- ametryn(Evik*)
- bromopropylate (Acarol*)
- cinmethylin (Argold*)
- crotoxyphos (Ciodrin, Decrotox*)
- DCPA (Dacthal*)
- diphenamid (Dymid*)
- disulfoton (DiSyston*, Ekanon*)
- endosulfan (Thiodan*)
- endrin (Hexadrin*)
- ethoprop (Mocap*)
- flufenoxuron (Cascade*)
- fluvalinate (tau-fluvalinate) (Mavrik*, Spur*)
- formetanate hydrochloride (Carzol*)
- mancozeb (Manzate*, Dithane*, Fore*)
- methanearsonic acid (MAA)
- neburon (Granurex*, Propuron*)
- pebulate (Tillam*)
- phorate (Geomet*, Thimet*)
- pirimiphos-methyl (Acetellic*)
- sethoxydim (Poast*)
- sulfosate (Touchdown*)
- terbufos (Counter*)
- thiocyclam hydrogen oxalate (Evisect*)
- thiodicarb (Larvin*, Nivral*))
- triforine (Denarin*, Funginex*)
Group III. Relatively Nonhazardous: These materials can be
applied with little harm to bees. Regardless, follow label instructions.
Relatively Non-Toxic
- 2,4-D butoxyethyl ester (Aqua-Kleen*)
- 2,4,5-T (2,3,5,-T)
- alachlor (Lasso*)
- aldicarb (Temik*)
- aldoxycarb (Standak*)
- alloxydim sodium (Kusagard*)
- amitraz (Taktic*)
- amitrole (Kytrol*)
- ammoniacal copper sulfate (Copac*)
- anilazine (Dyrene*)
- anthraquinone (Corbit*)
- atrazine (tech) (AAtrex*)
- azadirachtin (Margosan-O*)
- azamethiphos (Alfacron*)
- azocyclotin (Peropal*)
- Bacillus thuringiensis (Gnatrol*)
- benomyl (Benlate*)
- bentazon (Basagran*)
- bitertanol (Baycor*)
- Bordeaux mixture (Nutra-Spray*)
- bromacil (Hyvar*)
- bromadiolone (Boot Hill*, Maki*)
- bromofenoxim (Faneron*) (WP)
- bromoxynil (Emblem*)
- buminafos (Trakephon*)
- bupirimate (Nimrod*)
- butylate (Sutan+*)
- butylate (Anelda* Plus)
- captan (Captanex*)
- captfol (Haipen*)
- carbendazim (Delsene*)
- carbetamide (Carbetamex*)
- carboxin (Vitavax*)
- chinosol (Beltanol L*)
- chloramben (Amniben*)
- chloranil (Chloranil)
- chlorbromuron (Maloran*)
- chlordimeform (Chlordimeform)
- chlorflurenol (Maintain A*)
- chloridazon (Pyramin*)
- chlormequat chloride (Cycocel*)
- chlorobenzilate (Benzilan*)
- chlorophacinone (Caid*, Rozol*)
- chloropicrin (Chlor-O-Pic*)
- chlorothalonil (Bravo*)
- chlorotoluron (Dicuran*)
- chloroxuron (Tenoran*)
- chlorpropham (Taterpex*, Bud Nip*)
- clofentezine (Apollo* SC)
- copper oxide (Nordox*)
- copper oxychloride (form) (Recoup*)
- cyanazine (Bladex*)
- cycloate (Ro-Neet*)
- cycloxydim (Focus*)
- cyhexatin (Metaran*)
- cyproconazole (Sentinel*)
- dalapon (Dalacide*)
- daminozide (B-Nine*)
- dazomet (Basamid*)
- DCNA (Botran*)
- desmetryn (Semeron*)
- dibromochloropropane (Nemagon*)
- dicamba (Banvel*)
- dichlobenil (Casoron*)
- dichlofenthion (form) (VC-13 Nemacide*)
- dichloroprop-P (Duplosan* DP)
- dichlorprop (Polymone*)
- diclofop-methyl (Hoelon* 3EC)
- dicofol (Kelthane*)
- dienochlor (Pentac*)
- diflubenzuron (Dimilin*)
- dikegulac sodium (Atrimmec*)
- dimethirimol (Milcurb*)
- diniconazole-M (Spotless*)
- dinocap (Karathane*)
- diquat dibromide (Reward*)
- dithianon (Delan*)
- dithiocarbamates (Metam-sodium, Dithane*)
- diuron ((Seduron*)
- dodemorph acetate (E.C.) (Meltatox*)
- dodine (Melprex*)
- endothall (Entothal*)
- epoxiconazole (OPUS*)
- ethephon (Cerone*)
- ethidimuron (Ustilan*)
- ethion (Ethiol*)
- ethirimol (Ethirimol)
- ethofumesate (Nortron*)
- ethylfluralin (Sonalan*)
- fenaminosulf (Lesan*)
- fenamiphos (Nemacur*)
- fenarimol (Rubigan*)
- fenfuram (Pano-ram*)
- fenpropimorph (Funbas*)
- fentin hydroxide (Brestanid*)
- fenuron (Fenuron)
- ferbam (Carbamate*)
- fluometuron (Cotoran*)
- fluorodifen (Preforan*)
- fluoroglycofen (Complete*)
- folpet (Folpan*)
- fosamine ammonium (Krenite*)
- fuberidazole (Fuberidazol)
- furalaxyl (Fongarid*)
- gibberellic acid (ProGibb*, Gibrel*)
- glyodin (Glyodin)
- glyphosate (Round-Up*)
- glyphosate (Pondmaster*)
- guazatine (Kenopel*)
- indole-3-butyric acid (Hormodin*)
- iprodione (Chipco*)
- Isopropalin (Paarlan*)
- isoproturon (Alon*)
- lenacil (Venzar*)
- linuron (Lorox*)
- maneb (Manex*)
- MCPA (Chiptox*, Weedar*)
- MCPB (Thistrol*)
- mecoprop (Propal*)
- mecoprop-p (Duplosan*KV)
- MEMC (Bagalol*)
- mepiquat chloride (Pix*)
- metalaxyl (Ridomil*)
- metalaxyl (Apron*, Subdue*)
- metaldehyde (Slug N' Snail*)
- methamitron (Goltix*)
- methazole (Probe*)
- methoxychlor (Marlate* - EC Non-Toxic, Dusts toxic)
- methyl bromide (Meth-O-Gas*)
- Metiram (Polyram* DF)
- metobromuron (Patoran*)
- metolachlor (Dual*, Pennant*)
- metoxuron (Dosanex*)
- metribuzin (Sencor*)
- monalide (Potablan*)
- monolinuron (Aresin*)
- monuron (Monuron)
- MSMA (Diumate*, Daconate*)
- nabam (Spring-Bak*)
- napropamide (Devrinol*)
- naptalam acid (Alanap*)
- naptalam (Alanap*-L, Rescue*)
- nicotine (Nicotine)
- nitralin (Planavin*)
- nitrapyrin (N-Serve*)
- nitrofen (Nip*, Tok*)
- norflurazon (Evital*, Predict*)
- nuarimol (Trimdal*)
- oryzalin (Surflan*)
- ovex (Sappiran*)
- oxycarboxin (Plantvax*)
- oxyfluorfen (Goal*)
- oxythioquinox (Morestan*)
- paraquat (Gramoxone*, Starfire*)
- PCNB (Terraclor*, Turfcide*)
- pendimethalin (Prowl*)
- phenmedipham (Spin-Aid*, Betanal*)
- phosalone (Asofene*, Zolone*)
- picloram (Grazon*, Tordon*)
- pirimicarb (Pirimor*)
- PMA (Unisan*)
- prochloraz (Abavit*, Omega*)
- procymidone (Sumilex*)
- profluralin (Tolban*)
- prometon (Pramitol*)
- prometryn (Caparol*)
- pronamide (Kerb*)
- propachlor (Ramrod*)
- propam (Birgin*)
- propamocarb hydrochloride (Banol*, Prevex*)
- propargite (Comite*, Omite*)
- propazine (Milo-Pro*, Primatol*P)
- propineb (Airone*, Antracol*)
- prothiocarb (Previcur*)
- pyrethrins (EC toxic, sprays repellant effects)
- pyridate (Tough*)
- pyroquilon (Coratop*, Fongorene*)
- quinclorac (Facet*)
- quizalofop-ethyl (Assure*)
- rotenone (Prentox*, Prenfish*)
- ryania (Natur-Gro R-50)
- sabdilla (Sabdilla)
- sethoxydim (Poast*, Vantage*)
- simazine (Princep*)
- sulfur (Uniflow*, Sulfox*, Cosan*)
- TCA (TCA)
- terbacil (Sinbar*)
- terbumeton (Caragard*)
- terbutryn (Terbutrex*)
- tetradifon (Tedion*)
- thiabendazole (Arbortect*, Mertect*)
- thiophanate-methyl (Pinnacle*)
- thiram (AAtack*, Chipco*)
- triadimefon (Bayleton*)
- triadimenol (Baytan*)
- tribufos (Folex*, DEF*)
- trichlamide (Hataclean*)
- trichlorfon (Dipterex*, Proxol*)
- triclopyr (Garlon*, Pathfinder*, Remedy*)
- trietrazine (Trietrazine)
- trifluralin (Treflan*)
- triphenyltin hydroxide (Brestanid*)
- validamycin A (Validacin)
- vernolate (Vernam*)
- vinclozolin (Curalan*, Ornalin*)
- warfarin(Co-Rax*, Cov-R-Tox*)
- WSSA (Herbisan* 5(EXD, Sulfasan*)
- zineb (Cuprothex*)
- ziram (Ziram 76*)
* Brand name of proprietary product
Information taken from:
Farm Chemicals Handbook, '95, Meister Publishing Company.
Pollinator Protection, Johansen & Mayer, Wicwas
Press, 1990.
The New Pesticide User's Guide, Bert L. Bohmont, Reston
Publishing Company.
If you have had a serious pesticide kill and need to know the
pesticide responsible, dead bee samples must be sent to chemical
laboratories for analysis. This service is for hire and is not
always easily obtainable. Contact your county Extension office
for assistance.
Produced in cooperation with the Department of Entomology,
Auburn University. March, 1996
All educational programs conducted by Ohio
State University Extension are available to clientele on a nondiscriminatory
basis without regard to race, color, creed, religion, sexual orientation,
national origin, gender, age, disability or Vietnam-era veteran
status.
Issued in furtherance of Cooperative Extension work, Acts of
May 8 and June 30, 1914, in cooperation with the U.S. Department
of Agriculture, Keith L. Smith, Director, Ohio State University
Extension.
TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868
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