The Effect of Diluents on the Toxicity of Pure Ground Derris Root in Dusts1

Abstract

Pyrophyllite used as a diluent resulted in a higher mortality of Aphis rumicis than a clay or fibrous talc, both of which were less effective than an equal quantity of derris without a diluent. Slate dust and flaky talc were also inferior to pyrophyllite. Dosage-response tests in the field showed that 3-5 parts of rotenone were required with clay to produce mortality or protection of the foliage equal to 1 part of rotenone with pyrophyllite as a diluent. The test insects were the potato flea beetle, striped cucumber beetle, Mexican bean beetle, and cabbage worms.