| Popis: |
Laboratory bioassays were conducted to evaluate the effect of the diatomaceous earth (DE) formulation SilicoSec (Biofa GmbH, Munsingen, Germany), against two stored-product mite species, Tyrophagus putrescentiae (Shrank) and the predator Cheyletus malaccensis Oudemans. For this purpose, DE was applied in wheat, oat, rye, and maize, at the dose rates 0, 0.5, 1, and 2 g/kg grain. The mortality of the exposed mites was assessed after 24 h, 48 h, 7 d, and 14 d of exposure in the treated substrate. After this interval, the treated grains were checked for oviposition or progeny. The tests were conducted at 80% RH and at two temperatures, 20 and 25°C. Generally, for both species, mortality was higher at 25°C than at 20°C. For T. putrescentiae, at both temperatures, the mortality in grains treated with the highest DE rate was 100% after only 24 h of exposure, with the exception of maize at 20°C, where mortality was 91.7%. The mortality of C. malaccensis after 24 h of exposure to the treated grains, in th... |
