# Lawn Herbicides?



## DrStickles (Aug 23, 2014)

Dear CCD Forum Readers:

I know that neonicotinoids are currently receiving a lot of attention in discussions about Colony Collapse Disorder. But since there may be more than one way to depopulate a hive in the middle of the summer, I would like to share with you the text of an email I sent to [email protected] yesterday, describing my recent experience relative to lawn herbicide application:

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Dear Environmental Pollution Agency Staffers: 

Just wanted to pass along this observation, in case you should run across reports of similar experiences by other beekeepers. I'd be glad to provide more information at a later date if requested:

I am a hobby beekeeper with a total of about ten years experience. I lost 2 of my 3 hives this summer to a "mystery" condition--one in early July and the other early August. Both colonies were ultimately done in by wax moths, due to depopulation. Both had previously swarmed one or more times. In both cases, it seemed to take a long time for the new queen to "kick into gear." When she did, only a small number of eggs, larvae, and capped brood--mixed together with empty cells and in no particular pattern--were in evidence. Interestingly, in an area of the comb where a group of empty cells was available, at least one of the queens had laid a very solid pattern of eggs. There were no K-winged bees, no dead or dying bees in front of the hive, no abnormal smell, no shriveled or dry or ropey or oddly-positioned larvae, no sunken or discolored cell caps--no symptoms of "typical" bee diseases that I was aware of. There was an abundance of both pollen and sealed honey available from spring and early summer foraging activities. None of the brood combs were more than 3 years old, and most were only 1 or 2. Our KS State Naturalist was stumped. Just to be on the safe side, I did a home test for European Foul Brood, and it was negative.

This is my fourth year raising bees at this suburban residential location, and I have not seen anything like it before. The one variable I could point to as being "different" this year is that we had contracted with a lawn care company to apply selective herbicides and pre-emergents to our rather large (2/3 acre) lawn on a regular schedule. If there is another "different" thing, it might be that this year my bees quit gathering water at the bird bath I fill daily for them--and they subsequently refused to gather water from a 5-gallon chicken waterer I placed squarely in front of their entrances!

So… I suspect that my bees have been gathering water from small puddles after rains and after the lawn is irrigated (which it has been, most mornings) and using some of that water to dilute honey for feeding the brood. To my eye, the larvae all looked perfectly normal, but.. I'm wondering if some of those larvae were failing to thrive, and were being removed from their cells by nurse bees. And.. I'm wondering if other suburban bee keepers might be having similar experiences. 

I am not "blaming" anyone here. We've had good communication with our lawn chemical company--Scotts Lawn Service. I'm sure they are following industry, state, and federal standards and regulations. They provided a list of chemicals they would be using in advance, and--according to my research--none of those on their list* (save the one insecticide, which they assured us they would not use) is considered to be toxic to adult honeybees.

HOWEVER… as you may be aware.. there is a dearth of research available on the sub-lethal effects of common herbicides on honeybees, and their effects on queen fertility and larval viability. This has been a concern of Randy Oliver, who cited a well-designed study** in which the effects of paraquat (not one of those used on our lawn) on honeybee larvae were explored. Randy states the study found strong adverse effects on bee larvae at one part per trillion--as difficult as that may be to believe! I am also aware of at least one study*** that found adverse effects on butterfly larvae from exposure to fluazifop-p-butyl and sethoxydim (also not on the Ortho list).

Of course… my 2/3 acre lawn is not a covered petri dish, and this is not a controlled experimental study. I have neighbors on all sides--some of whom may have used insecticides on their lawns and flowers this year, for all I know. Or it could be something else entirely. I should note that my one remaining hive seems be thriving at this point (knock on wood)! But thanks for your concern and vigilance regarding potential bee kill issues. Again, I would be glad to provide additional information if requested. I would also welcome notice of any additional research along these lines you might be aware of.


*Herbicides I have record of having been applied:
Triclopyr
2,4-D
MCPP
Dicmaba
Prodiamine
Herbicides also on the Scotts list which may or may not have been applied:
Glyphosate
Simazine
MSMA

**Cited in Randy Oliver's "Sick Bees Part 18F7 Colony Collapse Revisited Part II: Pesticide Exposure" in the November 2013 issue of American Bee Journal: 

Cousin M, Silva-Zacarin E, Kretzschmar A, El Maataoui M, Brunet J-L, et al. (2013) Size changes in honey bee larvae oenocytes induced by exposure to paraquat at very low concentrations. PLoS ONE 8(5): e65693. doi:10.1371/journal.pone.0065693http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0065693

***Russell, C. & Schultz, C.B. (2010). Effects of grass-specific herbicides on butterflies: An experimental investigation to advance conservation efforts. Journal of Insect Conservation, 14, Issue 1, pp. 53-63. Abstract available at:
http://link.springer.com/article/10.1007/s10841-009-9224-3#page-2


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## DrStickles (Aug 23, 2014)

PS. I would be interested in hearing from any readers who have had similar experiences.


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