Common crop pesticides kill honeybee larvae in the hive

Courtesy of Penn State News:

UNIVERSITY PARK, Pa. — Four pesticides commonly used on crops to kill insects and fungi also kill honeybee larvae within their hives, according to Penn State and University of Florida researchers. The team also found that N-methyl-2-pyrrolidone (NMP) — an inert, or inactive, chemical commonly used as a pesticide additive — is highly toxic to honeybee larvae.

“We found that four of the pesticides most commonly found in beehives kill bee larvae,” said Jim Frazier, professor of entomology, Penn State. “We also found that the negative effects of these pesticides are sometimes greater when the pesticides occur in combinations within the hive. Since pesticide safety is judged almost entirely on adult honeybee sensitivity to individual pesticides and also does not consider mixtures of pesticides, the risk assessment process that the Environmental Protection Agency uses should be changed.”

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According to Frazier, the team’s previous research demonstrated that forager bees bring back to the hive an average of six different pesticides on the pollen they collect. Nurse bees use this pollen to make beebread, which they then feed to honeybee larvae. Continue reading