Abstract
Fenpropathrin (α-cyano-3-phenoxybenzyl 2, 2, 3, 3-tetramethylcyclopropanecarboxylate) was examined for toxicity to mites and for effect upon fecundity, paralyzing action and repellency. Fenpropathrin was highly toxic to adults of carmine mite, Tetranychus cinnabarinus BOISDUVAL and citrus red mite, Panonychus citri MCGREGOR, and its ovicidal activity was comparable to that of dicofol and amitraz. It weakened the feeding activity of adult mites, and consequently reduced the number of eggs laid. It also showed characteristic repellency which induced changes in mite's behavior on the host plants. Carmine mites treated with fenpropathrin at low concentrations moved away from treated leaves. When treated with fenpropathrin at 0.16ppm, mites hung on threads from the leaves, and this “spinning down” increased with the dose. The decrease in the number of mites leaving treated leaves at higher concentrations was attributed to the quick paralyzing action by fenpropathrin. More carmine mites spun down from completely treated plants than from partially treated ones, where they had a choice between treated and untreated parts of each plant. Most of the citrus red mites treated with 25ppm and 50ppm fenpropathrin spun down from the host plants within 9hr.
