Japanese Beetle treatment in proximity to honeybee colonies?

Asked February 27, 2020, 10:29 AM EST

A TVBA member has asked if Japanese beetle treatment (described in a request for consent to treat letter as "allowing ODA to apply a granular larvicide (Acelepryn® G) treatment to lawns and ornamental planting beds on your property or residence.") will impact his colonies, in specific developing eggs and larvae. Can you please advise on this? Thank you!

Washington County Oregon

1 Response

Great question. The short answer is that granular Acelepryn treatments (which contain the insecticide chlorantraniliprole) are of very low risk to bees. Acelepryn is a very low hazard insecticide and frequently recommend for pest management situations around bees. Furthermore, the granular formulation is one of the least hazardous formulations, because it does not drift off-target like sprays do. There was an excellent study that simulated a higher risk scenario using the same product. In the study they treated a plot of lawn with blooming clover. They then enclosed a bumble bee nest and compared the colony growth rate on the Acelepryn-treated plot, an untreatred plot and a plot treated with an insecticide known to be toxic to bees. What they found was that the bumble bees grew at the same rate on the Acelepryn and untreated plots, but experienced low growth when they were enclosed on the plot treated with the toxic insecticide.
Larson, J.L., Redmond, C.T. and Potter, D.A., 2013. Assessing insecticide hazard to bumble bees foraging on flowering weeds in treated lawns. PLoS one, 8(6).
You can access the article here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0066375

Finally, we are anticipating that if Japanese Beetle establishes in Oregon, it will result in increased insecticide use, which will effectively harm bees. Any effort to eradicate this pest will pay dividends down the road at helping bees.