Mortality of Bumble Bees in Commercial Low-Bush Blueberry Fields Dusted with Calcium Arsenate1

Abstract

The oral toxicity of calcium arsenate (as the clement) to the worker bumble bee was determined by feeding measured doses of poison to bees collected from undusted areas and recording mortality at regular intervals. The LD50 (at 96 hours) was approximately 5 p.p.m. (1.4 to 2.1 micrograms per bee). A detailed description of a technique to measure micrograms of ingested arsenic is also given. Data are presented to show that the treatment of commercial blueberry fields with arsenical dusts is contributing to a reduction in the worker bee populations.