Field evaluation of neem and Canola oil for the selective control of the honey bee (Hymenoptera : Apidae) mite parasites Varroa jacobsoni (Acari : Varroidae) and Acarapis woodi (Acari : Tarsonemidae)

Neem oil, neem extract (neem-aza), and canola oil were evaluated for the ma nagement of the honey bee mite parasites Varroa jacobsoni (Oudemans) and Ac arapis woodi (Rennie) in field experiments. Spraying neem oil on bees was m ore effective at controlling V. jacobsoni than feeding oil in a sucrose-bas ed matrix (patty),feeding neem-aza in syrup, or spraying canola oil. Neem o il sprays also protected susceptible bees from A. woodi infestation. Only n eem oil provided V. jacobsoni control comparable to the known varroacide fo rmic acid, but it was not as effective as the synthetic product Apistan (ta u-fluvalinate). Neem oil was effective only when sprayed six times at 4-d i ntervals and not when applied three times at 8-d intervals. Neem oil spray treatments had no effect on adult honey bee populations, but treatments red uced the amount of sealed brood in colonies by 50% and caused queen loss at higher doses. Taken together, the results suggest that neem and canola oil show some promise for managing honey bee parasitic mites, but the negative effects of treatments to colonies and the lower efficacy against V. jacobs oni compared with synthetic acaricides may limit their usefulness to beekee pers.