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Pesticides in and around the hive

Reed M. Johnson The Ohio State University – OARDC,

Wooster, OH johnson.5005@osu.edu

Overview

• What are pesticides?

• Pesticides and drugs in beekeeping

• Determining a toxic dose (LD50)

• Routes of exposure (formulation, function and the law)

• Some pesticides are more toxic than others

• Avoiding pesticide damage

• What to do if you suspect a pesticide kill

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What is a “pesticide”? A pesticide is any substance or mixture of substances intended for:

• preventing, • destroying, • repelling, or • mitigating any pest. Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides, and various other substances used to control pests. http://www.epa.gov/pesticides/about/index.htm#what_pesticide

• Insects

• Weeds

• Rodents

• Fungi

• Bacteria and viruses

• Mites

Insecticides

Herbicides

Rodenticides

Fungicides

Antimicrobials

Miticides

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Which substances are regulated as drugs and which are regulated as

pesticides?

Food and Drug Adminsitration (FDA) is responsible for regulating animal drugs; however, some products to control external parasites come under the jurisdiction of the Environmental Protection Agency (EPA). FDA and EPA work together to ensure adherence to all applicable laws and regulations. In general, flea and tick products that are given orally or by injection are regulated by FDA.

http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm16983.htm

Drugs to control pests and pathogens

American Foulbrood (Paenbacillus larvae)

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oxytetracycline

tylosin

Nosema apis and Nosema ceranae

Tom Webster, http://www.extension.org/pages/27064/nosema-ceranae-the-inside-story

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fumagillin

Varroa destructor

USDA K5111-10, Scott Bauer

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tau-fluvalinate (pyrethroid)

coumaphos (organophosphate)

fenpyroximate (pyrazole)

amitraz (formamadine)

thymol (monoterpenoid)

oxalic and formic acids (organic acids)

hops beta-acids (organic acid)

http://www.centralapiary.com/uploads/products/apistan_label.pdf

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1.4 g pyrethroid

2.8 g organophosphate 1.0 g formamadine

49 g mono- terpenoids

1.8 g organic acid

0.7g phenyl-pyrazole

Quentin Massys

How can bees tolerate “pesticides” in the hive?

Paracelsus 1493-1541

The Father

of Toxicology

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drugs

poisons

"All things are poison and nothing is without poison, only the dose permits something not to be poisonous." -Paracelsus 1493-1541

drugs

poisons

“The dose makes the poison" -Paracelsus 1493-1541

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therapeutic

harmful

deadly

no effect

therapeutic

harmful

deadly

no effect

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What is a safe dose? What is a toxic dose? Lethal Dose 50% (LD50)

Lab LD50 Bioassays

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pesticide

collect brood

age adults 3-4 d.

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pesticide

collect brood

age adults 3-4 d.

count dead

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Wide variability in insecticide toxicity to bees

- Some pesticides have low toxicity to bees and can be safely used inside the hive

- Others have high toxicity to bees and should not be used if bees will contact them

- LD50 is useful for comparing toxicity: http://www.ipmcenters.org/Ecotox/index.cfm

Limitations of LD50 testing

Advantages: - Reliable and straightforward to compare - Topical, contact, oral LD50 (or LC50) - Adults or larvae - Workers, queens or drones Disadvantages: - Does not test colony-level effects - Does not test long-term or sub-lethal effects

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Risk = Hazard x Exposure LD50 Formulation

Function Label restrictions and Laws

Formulation determines bee and colony exposure

- Impregnated material - Seed treatment - Bait - Granular - Concentrates / suspensions (spray) - Wettable powder (spray) - Dust - Microencapsulated

better

worse

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Jon Sullivan, http://en.wikipedia.org/wiki/File:Bees_Collecting_Pollen_2004-08-14.jpg

Function determines bee exposure

1. Stomach poisons – enter through mouth

2. Contact poisons – enter through epidermis 3. Fumigants – enter through respiratory system

4. Systemic action – present in plant fluids

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Label restrictions determine bee exposure

PROTECTION OF LIVESTOCK Dangerous to bees. DO NOT spray any plants in flower when bees are foraging. Spray in the early morning when bees are not actively foraging.

http://codes.ohio.gov/oac/901%3A5-11-02

(15) Apply or cause to be applied any pesticide that is required to carry a special warning on its label indicating that it is toxic to honey bees, over an area of one-half acre or more in which the crop-plant is in flower unless the owner or caretaker of any apiary located within one-half mile of the treatment site has been notified by the person no less than twenty-four hours in advance of the intended treatment; provided the apiary is registered and identified as required by section 909.02 of the Revised Code, and that the apiary has been posted with the name and telephone number of the owner or responsible caretaker. (16) Apply pesticides which are hazardous to honey bees at times when pollinating insects are actively working in the target area; however, application of calyx sprays on fruits and other similar applications may be made.

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http://www.irac-online.org

Insecticides: Organophosphates

- Nerve action - Relatively high toxicity to humans - Contact, stomach and systemic toxicity - LD50 range: 0.018 – 59.8 micrograms / bee

Chlorpyrifos LD50 = 0.059 Malathion LD50 = 0.20 Coumaphos LD50 = 20.3

Lorsban (Dow AgroSciences) Spectracide Malathion Checkmite+ (Bayer)

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Insecticides: Carbamates

- Nerve action - Somewhat toxic to humans and bees - Contact, stomach and systemic toxicity - LD50 range: 0.16 – 25 micrograms / bee

Aldicarb LD50 = 0.285 Carbaryl LD50 = 1.02 Thiodicarb LD50 > 25

Temik (Bayer) Sevin (GardenTech) Larvin (Bayer)

Insecticides: Pyrethroids

- Nerve action - Contact poisons - Based on natural product in chrysanthemums - Relatively safe for humans, highly toxic for bees - Repellent to bees - LD50 range: 0.0015 – 3.94 micrograms / bee

Bifenthrin LD50 = 0.015 Pyrethrum LD50 = 0.02 Fluvalinate LD50 = 1.9

Ortho Home Defense Max Pyrethrum 5EC Apistan (Wellmark)

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Insecticides: Neonicotinoids - Nerve action - Analogs of nicotine - Systemic, contact and stomach poison - Relatively safe for humans, toxic for bees - LD50 range: 0.024 – 37.8 micrograms / bee

Imidacloprid LD50 = 0.044 Dinotefuran LD50 = 0.047 Thiacloprid LD50 = 37.8

Bayer Advanced Safari (Valent) Calypso (Bayer)

Insecticides: Diamides

- nerve and muscle action - contact poison - Relatively safe for humans and bees - LD50 > 100 micrograms / bee

Chlorantraniliprole LD50 > 100 Flubendiamide LD50 > 200

Rynaxypyr (DuPont)

Belt (Bayer)

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Other Insecticides

Growth regulators: Diflubenzuron, methoprene - LD50 > 100 micrograms / bee to adults

- Cause problems in brood development Energy metabolism: Rotenone, fenpyroximate - LD50 0.024 – 60 micrograms / bee Lipid synthesis inhibitors: Spirotetramat - LD50 > 100 micrograms / bee

Fungicides

- May be applied during bloom - High exposure is possible - Can be found in pollen (up to 400 ppm) - LD50 > 10 micrograms / bee - High doses may have effects on brood??

Mussen et al., 2004; http://dx.doi.org/10.1603/0046-225X-33.5.1151

Ziram Rovral Captan

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Herbicides

- Kill flowering “weeds” bees on which bees feed - Bees may be present - High exposure is possible - LD50 > 100 micrograms / bee - Possible effects at high doses??

Paraquat 2,4-D

Planning for pesticide exposure

Applicators

An applicator can call the Ohio Department of Agriculture at 614-728-6373 and obtain a list of registered apiaries by location. This file is sent electronically usually within 24 hours of the request.

Beekeepers Post your name and phone number in the apiary. Communicate with neighbors so that they are aware that your apiary exists.

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Preparing a hive for pesticide exposure 1. Move the hive someplace else 2. Confine bees to the hive (but beware overheating) -Screen off entrance -Screen lid -Screen whole hive -Cover hive with wet burlap sack

Do not return or release bees for at least 24 hours

Dealing with a suspected pesticide kill 1. Take photos and record the location of apiary, number

of hives affected, problems observed

2. Collect 50-100 affected bees from bottom board in plastic bag, store in freezer (but don’t take them all)

3. Contact your county apiary inspector and the Ohio Department of Agriculture (614-728-6373)

4. Report the incident to USEPA: beekill@epa.gov

5. Get bees tested for pesticide residues: Contact Roger Simonds (Roger.Simonds@ams.usda.gov ) at USDA-AMS Lab in Gastonia, NC ($300 / sample)

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Summary 1. Some pesticides are more toxic to bees than

others

2. Formulation and label guidelines can limit bees’ exposure

3. Both exposure and toxicity are required to cause harm

4. Some pesticides are useful in beekeeping

5. Bees can have all sorts of problems and can get exposed to many different pesticides: Proving that a particular pesticide is responsible for a bee kill is challenging

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Suggested reading: 1. Atkins E (1992) Injury to honey bees by poisoning. The Hive

and the Honey Bee. Hamilton, IL: Dadant & Sons, Inc. pp. 1153–1208.

2. How to Reduce Bee Poisoning from Pesticides PNW 591, A Pacific Northwest Extension Publication. 2006. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/20772/pnw591.pdf

3. Pesticide Risk Assessment for Pollinators: Executive . Summary from SETAC . 2011

http://www.setac.org/node/265 Data: IPM Centers Pesticide Data Page http://www.ipmcenters.org/pesticides.cfm US EPA Databases http://www.epa.gov/opp00001/science/databases_pg.htm Insecticide Resistance Action Committee Mode of Action Guide http://www.irac-online.org