5/17/16

Honey Bee Toxicology: An overview of pes;cides and poisons in the hive Reed M. Johnson [email protected]

Paracelsus 1493-1541 The Father of Toxicology

Portrait by Quentin Massys

1

5/17/16

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

drugs

2

5/17/16

Toxic Gasses Carbon dioxide

-  Induces queens to begin laying eggs -  Reduces longevity of workers

Toxic Pollen

querce;n

3

5/17/16

Toxic Nectar Caffeine Nico;ne Amygdalin Bees may prefer nectar that is toxic Learn to avoid high concentra;ons

Toxic Honey

Hydroxymethylfurfural (HMF) Fructose is naturally converted to toxic HMF over ;me

4

5/17/16

Toxins produced by microorganisms

Aflatoxin B1

Aflatoxins are produced by Aspergillus fungi growing on pollen and bee bread

Bees have ways of dealing with exposure to natural toxins •  Detoxifica;on •  Avoidance •  Dilu;on Do these same processes work for modern pes;cides?

5

5/17/16

What is a “pes;cide”? •  •  •  •  •  • 

Insects Weeds Rodents Fungi Bacteria and viruses Mites

Ø Insec;cides Ø Herbicides Ø Roden;cides Ø Fungicides Ø An;microbials Ø Mi;cides

Drugs to control pests and pathogens

American Foulbrood (Paenbacillus larvae)

6

5/17/16

oxytetracycline

tylosin

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

Nosema apis and Nosema ceranae

7

5/17/16

fumagillin

Varroa destructor

USDA K5111-10, ScoC Bauer

8

5/17/16

coumaphos thymol (organophosphate) (monoterpenoid) tau-fluvalinate hops beta-acids (pyrethroid) oxalic and (organic acid) amitraz formic acids (formamadine) (organic acids) fenpyroximate (pyrazole)

49 g mono- terpenoids 1.4 g pyrethroid 0.7g phenylpyrazole

1.0 g formamadine

1.8 g organic acid

2.8 g organophosphate

9

5/17/16

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

Quentin Massys

no effect therapeutic

harmful deadly

10

5/17/16

no effect

harmful

therapeutic

deadly

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

11

5/17/16

Lab LD50 Bioassays

collect brood age adults 3-4 d.

pes;cide

12

5/17/16

13

5/17/16

collect brood age adults 3-4 d.

pes;cide count dead

14

5/17/16

15

5/17/16

bifenthrin LD50 = 0.01 micrograms / bee

tau-fluvalinate LD50 = 10 micrograms / bee

16

5/17/16

Wide variability in insec;cide toxicity to bees -  Some pes;cides 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: hcp://www.ipmcenters.org/Ecotox/index.cfm

hcp://cfpub.epa.gov/ecotox/

17

5/17/16

Lab LD50 tes;ng Advantages: - Reliable and straighjorward to compare -  Topical, contact, oral LD50 (or LC50) -  Adults or larvae -  Possible to test workers, queens and drones Disadvantages: -  Does not test colony-level effects -  Does not test long-term or sub-lethal effects

Risk = Hazard x Exposure LD50

FormulaXon FuncXon Label restricXons and Laws

18

5/17/16

Federal Insec;cide Fungicide and Roden;cide Act (FIFRA) of 1947, revised 1972, 1988, 1996

“unreasonable adverse effects on the environment.” Risk analysis of environmental effects includes a cost-benefit analysis Not the same as the “precauXonary principle” used in the European Union

Risk Quo;ent (RQ) =

Exposure (lb. a.i. / acre) LD50 (µg / bee)

Level of Concern (LOC) reached when RQ > 0.4 Historically, reduces mortality to 10% Pollinator Risk Assessment Framework Agency White Paper, US EPA, 2012

19

5/17/16

c

The Universe of Insecticides

Insec;cides: Organophosphates -  Nerve ac;on -  Rela;vely high toxicity to humans

Lorsban Chlorpyrifos LD50 = 0.059

Malathion Malathion LD50 = 0.20

Checkmite+ (Bayer) Coumaphos LD50 = 20.3

20

5/17/16

Insec;cides: Carbamates -  Nerve ac;on -  Somewhat toxic to humans

Temik (Bayer) Aldicarb LD50 = 0.285

Sevin Carbaryl LD50 = 1.02

Larvin (Bayer) Thiodicarb LD50 > 25

Insec;cides: Pyrethroids -  Nerve ac;on -  Based on natural product in chrysanthemums -  Rela;vely safe for humans -  Repellent effect on bees -  Contact toxicity

Ortho Home Pyrethrum Apistan Defense Max 5EC (Wellmark) Bifenthrin LD50 = 0.015

Pyrethrum LD50 = 0.02

Fluvalinate LD50 = 1.9

21

5/17/16

Insec;cides: NeonicoXnoids -  Nerve ac;on -  Analogs of nico;ne - rela;vely safe for humans

Bayer Advanced Imidacloprid LD50 = 0.044

Safari (Valent) Dinotefuran LD50 = 0.047

Assail

(United Phosphorus) Acetamiprid LD50 = 7.07

Insec;cides: New Rela;ves of NeonicoXnoids

Sivanto (Bayer) Flupyradifurone LD50 = 122

Transform (Dow) Sulfoxaflor LD50 = 0.13

22

5/17/16

Insec;cides: Diamides -  nerve and muscle ac;on -  contact poison -  rela;vely safe for humans

Lumivia (DuPont) Chlorantraniliprole LD50 > 100

Belt (Bayer) Flubendiamide LD50 > 200

Cyazapyr (DuPont) Cyantraniliprole LD50 = 0.55

Other Insec;cides Insect Growth Regulators (IGRs): 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

23

5/17/16

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

Captan

Rovral

Ziram

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

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??

2,4-D

Paraquat

24

5/17/16

“bee safe” insec;cide

Cytochrome P450 monooxygenases detoxify

25

5/17/16

SBI Fungicide

“bee safe” insec;cide

Risk = Hazard x Exposure LD50

FormulaXon FuncXon Label restricXons and Laws

26

5/17/16

Figure 3.1, “Risk assessment for bees”, EFSA, 2012

FormulaXon determines bee and colony exposure becer

worse

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

27

5/17/16

Systemicity determines exposure Guca;on water Pollen Nectar

Bee-life.eu

Bayer CropScience

Purdue Extension

Crop type determines exposure

hcp://water.usgs.gov/nawqa/pnsp/usage/maps/

28

5/17/16

Label restricXons 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 ac;vely foraging.

ApplicaXon rate determines bee exposure

29

5/17/16

hcp://www.cdms.net/Label-Database

hcp://www.cdms.net/Label-Database

30

5/17/16

hcp://www.cdms.net/Label-Database

31

5/17/16

32

5/17/16

Bee Hazard Icon •  Highly toxic neonico;noids: Imidacloprid, dinotefuran, clothianidin, thiamethoxam •  Limits to applica;on –  When blooming –  When bees are foraging

33

5/17/16

Big Changes in Regulatory Risk Assessment

The Hive and the Honey Bee

Old Protec;on Goal: Stop Bee Kills

New Pollinator ProtecXon Goals: 1.  Delivery of pollinaXon services 2.  ProducXon of honey and hive products 3.  Biodiversity of pollinators EPA: Pollinator Risk Assessment Framework Agency White Paper, US EPA, 2012. hcp://www.regula;ons.gov/#!documentDetail;D=EPA-HQ-OPP-2012-0543-0004 EFSA: ScienXfic Opinion on the science behind the development of a risk assessment of Plant ProtecXon Products on bees (Apis mellifera, Bombus spp. and solitary bees), EFSA, 2012. hcp://www.efsa.europa.eu/en/efsajournal/pub/2668.htm

34

5/17/16

Tier 1: Laboratory studies on adults and larvae Tier 2: Semi-field studies with whole colonies in tents Tier 3: Full field studies with treated crop

Summary 1. Bees have always been exposed to toxic compounds 2. Both exposure and toxicity are required to cause harm 3. Insec;cides are riskiest pes;cides for bees 4. Formula;on, rate and ;ming of applica;on limit bees’ exposure 5. Pes;cide risk assessment is changing

35

5/17/16

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 Pes;cides PNW 591, A Pacific Northwest Extension Publica;on. 2006. hcp://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/20772/ pnw591.pdf 3.  Pes;cide Risk Assessment for Pollinators: Execu;ve Summary from SETAC. 2011 hcp://www.setac.org/node/265 Data: IPM Centers Pes;cide Data Page hcp://www.ipmcenters.org/pes;cides.cfm US EPA Databases hcp://www.epa.gov/opp00001/science/databases_pg.htm Insec;cide Resistance Ac;on Commicee Mode of Ac;on Guide hcp://www.irac-online.org CDMS Label database hcp://www.cdms.net/labelsmsds/lmdefault.aspx

36