The effect of synthetic pyrethroid insecticides on honey bees in Indiana: Laboratory studies and a survey of beekeepers and pesticide applicators

Insecticides are an important component of the row crop production system in Indiana. Concern for the safe use of these products has lead to a system of regulating the application of pesticides that is designed to protect the public, the environment and the applicator. One non-target organism that is affected by some pesticide applications is the honey bee. Because of its social nature, the impact of pesticides on bees is sometimes expressed as detrimental effects on the colony to which the exposed bee delivers her contaminated nectar or honey. This study looked at several aspects of the honey bee/pesticide problem, including one class of insecticides about which there is controversy concerning their impact on bees. This class is the synthetic pyrethroids. These studies found that the relative toxicity to adult bees of the four products examined was: permethrin $\u3e$ flucythrinate $\u3e$ fenvalerate $\u3e$ fluvalinate, in decreasing toxicity. The toxicity of these products was also shown to increase at 18$\sp\circ$C and 12$\sp\circ$C as compared to their toxicity at 25$\sp\circ$C. These are temperatures in a range which might be experienced by bees in a colony in Indiana during the winter. This study also demonstrated that no synergism or antagonism was seen when permethrin and fluvalinate were fed to adult bees together with carbaryl, paraquat or mancozeb. This study did demonstrate that some colonies were more resistant to permethrin and carbaryl than others and that this resistance was related to the race of the queen heading the colony. Beekeepers, public pesticide applicators and private pesticide applicators were surveyed to examine their knowledge of and attitudes toward the poisoning of honey bee colonies by pesticides. The response rate was not significantly different among the groups. The mean response rate was 75%. Less than 10% of the beekeepers and none of the applicators reported any knowledge of specific incidents in which bees were poisoned by pesticides in 1986. Both the beekeepers and the applicators were concerned about this issue and both groups indicated a willingness to take specific actions to attempt to prevent future poisonings. Each of the three groups showed a poor level of knowledge about pesticides as they relate to bees and about integrated pest management