Pesticide toxicity to bees: Wikis

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Pesticides vary in their effect on bees. Contact insecticides, which kill by touching the organism, affect worker bees directly sprayed. Systemic insecticides, those incorporated by treated plants, can contaminate nectar or pollen, which then kills bees in the hive.

Dust and wettable powder pesticides tend to be more hazardous to bees than solutions or emulsifiable concentrates.

Actual damage to bee populations is a function of the degree of toxicity of the compound, in combination with the mode of application; a highly potent insecticide applied only to the soil, for instance, would be expected to kill mainly soil-dwelling insects, such as grubs or mole crickets, and not bees.

Contents

Classification of pesticide toxicity

Insecticide toxicity is generally measured using LD50 – the exposure level that causes 50% of the population exposed to die. Toxicity thresholds are generally set at

  • highly toxic (acute LD50 less than 2μg/bee)
  • moderately toxic (acute LD50 2ug/bee to 10.99μg/bee)
  • slightly toxic (acute LD50 11ug/bee to 100μg/bee)
  • non-toxic (acute LD50 more than 100μg/bee) to adult bees.

[1] [2]

LD50 and Colony Collapse Disorder

LD50 does not explain any relationship, or lack thereof, to Colony Collapse Disorder. LD50 is an incomplete measure of toxicity to social insects like honeybees (Apis mellifera) because it is a measure of individual toxicity, not colony toxicity. It does not account for the ways bee behavior can mitigate or exacerbate effects of the pesticide on the colony. For example, a moderate to low toxicity pesticide (by LD50 measurement) used in granular form that is collected and concentrated along with pollen might have little toxicity to adult bees, but devastate the colony by its indirect effect on hive reproduction or mortality rate of larvae or young bees. On the other hand, a pesticide that is so toxic that the exposed bees die in the field can be less dangerous to the colony than a less toxic pesticide that allows the exposed bees to return to the hive and contaminate their fellows. Likewise, a highly toxic pesticide (according to LD50 measures) is "safe" for bees if it is applied on a grass lawn or other location without blooming flowers that attract bees. Furthermore, LD50 studies are conducted against adult bees and do not measure the effects on larvae, etc.

Bee kill rate per hive

The kill rate of bees in a single bee hive can be classified as:

< 100 bees per day - normal die off rate
200-400 bees per day - low kill
500-900 bees per day - moderate kill
> 1000 bees per day - high kill

[3]

Toxicity of pesticides to bees

Common name (ISO) Examples of Brand names Pesticide Class length of residual toxicity Comments Bee toxicity
Aldicarb Temik Carbamate apply 4 weeks before bloom Relatively non-toxic
Carbaryl [4] Sevin,

(b) Sevin XLR

Carbamate High risk to bees

foraging even 10 hours after spraying; 3 – 7 days (b) 8 hours @ 1.5 lb/acre (168 g/Ha) or less.

Bees poisoned with carbaryl can take 2–3 days to die, appearing inactive as if cold. It allows them time to take contaminated nectar and pollen back to the colony. Some crops treated with Sevin under the wrong conditions (in bloom, using a dust formulation, with large numbers of bees in the field) have been responsible for disastrous kills. Sevin is one of the United States' most widely used insecticides for a wide variety of insect pests. It is also one of the most toxic to honey bees, in certain formulations. These should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. 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 poisoning. highly toxic
Carbofuran [5] Furadan Carbamate 7 – 14 days U.S. Environmental Protection Agency ban on use on crops grown for human consumption (2009) carbofuran (banned in granular form) highly toxic
Methomyl [6] Lannate, Nudrin Carbamate 2 hours + Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
Methiocarb Mesurol Carbamate highly toxic
mexacarbate Zectran Carbamate highly toxic
Pirimicarb Pirimor, Aphox Carbamate Relatively non-toxic
Propoxur [7] Baygon Carbamate highly toxic
Acephate [8] Orthene Organophosphate 3 days Moderately toxic
Azinphos-methyl [9] Guthion, Methyl-Guthion Organophosphate 2.5 days banned in the European Union since 2006. [10] highly toxic
Chlorpyrifos [11] Dursban, Lorsban Organophosphate banned in the US for home and garden use Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
Coumaphos [12] Checkmite Organophosphate This is an insecticide that is used inside the beehive to combat varroa mites and small hive beetles, which are parasites of the honey bee. Overdoses can lead to bee poisoning. Relatively non-toxic
Demeton[13] Systox Organophosphate <2 hours highly toxic
Demeton-S-methyl Meta-systox Organophosphate Moderately toxic
Diazinon [14] Spectracide Organophosphate Residential uses of diazinon were outlawed in the U.S. in 2004. Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
dicrotophos Bidrin Organophosphate highly toxic
Dichlorvos[15] DDVP, Vapona Organophosphate highly toxic
Dimethoate [16] Cygon, De-Fend Organophosphate 3 days Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
Fenthion [17] Entex, Baytex, Baycid, Dalf, DMPT, Mercaptophos, Prentox, Fenthion 4E, Queletox,Lebaycid Organophosphate Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
Fenitrothion [18] Sumithion Organophosphate highly toxic
fensulfothion Dasanit Organophosphate highly toxic
fonofos Dyfonate EC Organophosphate 3 hours List of Schedule 2 substances (CWC) highly toxic
Malathion Malathion USB, ~ EC, Cythion, maldison, mercaptothion Organophosphate >8 fl oz/acre (58 L/km²) ⇒ 5.5 days highly toxic
Methamidophos [19] Monitor, Tameron Organophosphate Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
Methidathion [20] Supracide Organophosphate Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
methyl parathion parathion Penncap-M Organophosphate 5–8 days 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 ingredient. 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 collected 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 poisoned by micro-encapsulated methyl parathion, so a beekeeper potentially could lose replacement bees for those already poisoned by the pesticide. It is, therefore, strongly recommended by experts that this formulation be used only when honey bee exposure is not a possibility.

It is classified as a UNEP Persistent Organic Pollutant and WHO Toxicity Class, "Ia, Extremely Hazardous".

highly toxic
mevinphos Phosdrin Organophosphate highly toxic
Monocrotophos[21] Azodrin Organophosphate Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
naled Dibrom Organophosphate 16 hours highly toxic
Omethoate Organophosphate Should never be sprayed on flowering crops especially if bees are active and the crop requires pollination. highly toxic
oxydemeton-methyl Metasystox-R Organophosphate <2 hours highly toxic
phorate Thimet EC Organophosphate 5 hours highly toxic
Phosmet [22] Imidan Organophosphate highly toxic
phosphamidon Dimecron Organophosphate highly toxic
pyrazophos Afugan Organophosphate fungicide highly toxic
tetrachlorvinphos Rabon, Stirofos, Gardona, Gardcide Organophosphate highly toxic
Trichlorfon, Metrifonate Dylox, Dipterex Organophosphate 3 – 6 hours Relatively non-toxic
Permethrin [23] Ambush, Pounce Synthetic pyrethroid 1 – 2 days safened by repellency under arid conditions. Permethrin is also the active ingredient in insecticides used against the Small hive beetle, which is a parasite of the beehive in the temperate climate regions. highly toxic
Cypermethrin [24] Ammo, Raid Synthetic pyrethroid Less than 2 hours Cypermethrin is found in many household ant and cockroach killers, including Raid and ant chalk. highly toxic
Fenvalerate [25] Asana, Pydrin Synthetic pyrethroid 1 day safened by repellency under arid conditions highly toxic
Resmethrin[26] [27]

[28] [29] [30]

Chrysron, Crossfire, Pynosect, Raid Flying Insect Killer, Scourge, Sun-Bugger #4, SPB-1382, Synthrin, Syntox, Vectrin, Whitmire PT-110 Synthetic pyrethroid highly toxic
Methoxychlor [31] DMDT, Marlate Chlorinated cyclodiene 2 hours available as a General Use Pesticide highly toxic
Endosulfan [32] Thiodan Chlorinated cyclodiene 8 hours banned in European Union (2007?), New Zealand (2009) moderately toxic
Clothianidin Neonicotinoid Banned in Germany

In June 2008, the Federal Ministry of Food, Agriculture and Consumer Protection (Germany) suspended the registration of eight neonicotinoid pesticide seed treatment products used in oilseed rape and sweetcorn, a few weeks after honey bee keepers in the southern state of Baden Württemberg reported a wave of honey bee deaths linked to one of the pesticides, clothianidin.[33]

Imidacloprid Confidor, Gaucho, acetamiprid, clothianidin, nitenpyram, thiacloprid, thiamethoxam, Kohinor, Admire, Advantage, Merit, Confidor, Hachikusan, Premise, Prothor, and Winner Neonicotinoid (see also Imidacloprid effects on bee population)Banned in France since 1999 highly toxic
dicofol Acaricide Relatively non-toxic
petroleum oils Relatively non-toxic
2,4-D [2] ingredient in over 1,500 products Synthetic auxin herbicide Relatively non-toxic

Source: Protecting Bees When Using Insecticides University of Nebraska Lincoln, Extension, May 1998

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Common insecticides toxic to bees and used on soybeans

Many insecticides used against soybean aphids are highly toxic to bees.

  • Orthene 75S (acephate)
  • Address 75 WSP (acephate)
  • Sevin (Carbaryl)
  • Lorsban 4E (Chlorpyrifos)
  • Dimate (Dimethoate)
  • Steward 1.25 SC (Indoxacarb)
  • Lannate (Methomyl)
  • Cheminova Methyl 4EC (Methyl Parathion)
  • Penncap M (microencapsulated Methyl Parathion)
  • Tracer (Spinosad)

[34]

Highly toxic and banned in the US

Lawsuit against the EPA in the United States

In August 2008, the National Resources Defense Council, a New York environmental advocacy group, filed a lawsuit against the federal Environmental Protection Agency accusing the agency of withholding information about the risks pesticides pose to honeybees. [35]

See also

References

  1. ^ [1] Pollinator protection requirements for Section 18 Emergency Exemptions and Section 24(c) special local need registration in Washington State; Registration Services Program Pesticide Management Division Washington State Dept of Agriculture, Dec 2006
  2. ^ Hunt, G.J.; Using honey bees in pollination Purdue University, May 2000
  3. ^ Radunz, L. and Smith, E. S. C. [http://www.nt.gov.au/d/Content/File/p/Anim_Dis/677.pdf Pesticides Hazard to Honey Bees] Entomology, Darwin, Australia
  4. ^ carbaryl
  5. ^ carbofuran
  6. ^ methomyl
  7. ^ propoxur
  8. ^ acephate
  9. ^ azinphos-methyl
  10. ^ Scott, Alex (August 4, 2008). "Europe Rejects Appeal for Use of Azinphos-methyl Pesticide". Chemical Week. http://www.chemweek.com/envirotech/regulatory/13435.html. Retrieved 2008-08-11. 
  11. ^ chlorpyrifos
  12. ^ coumaphos
  13. ^ demeton
  14. ^ diazinon
  15. ^ dichlorvos
  16. ^ dimethoate
  17. ^ fenthion
  18. ^ fenitrothion
  19. ^ methamidophos
  20. ^ methidathion
  21. ^ monocrotophos
  22. ^ phosmet
  23. ^ permethrin
  24. ^ cypermethrin
  25. ^ esfenvalerate
  26. ^ resmethrin
  27. ^ Resmethrin Technical Fact Sheet - National Pesticide Information Center
  28. ^ Pyrethrins and Pyrethroids Fact Sheet - National Pesticide Information Center
  29. ^ Resmethrin Pesticide Information Profile - Extension Toxicology Network
  30. ^ MSDS for Scourge' Formula II
  31. ^ methoxychlor
  32. ^ endosulfan
  33. ^ "Emergency Pesticide Ban for Saving the Honeybee"
  34. ^ Commonly Used Insecticides for Soybeans Kansas State University Extension, Aug 2004
  35. ^ EPA sued after allegations Bayer pesticide killing honeybees

External links


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