Lethality of Inert Dust Materials to Kalotermes minor Hagen and Their Role as Preventives in Structural Pest Control

Abstract

Samples of 162 insecticide diluents and other finely divided inert materials were first screened in a pilot test in which drywood termites were placed in 1 cc. of the material in 100-ml. beakers, then in a test in which they were confined with blocks of wood that had been dusted at all air velocity of 1,400 feet per minute in a specially constructed wind tunnel. In the latter tests, the four outstanding groups of materials, in descending order of effectiveness, were silica gels, aerogels. or precipitates> montmorillonite days=attapulgite clays> diatomites. In tests made in attics of residences, blocks of wood were placed in a number of locations representing different distances and degrees of accessibility from the point of discharge of the dust. After the dust was applied the wood blocks were taken to the laboratory and termites were confined with them. These tests revealed a property of the sorptive dusts not evaluated in the pilot or wind-tunnel tests, namely, their bulk density. The lighter materials were more uniformly distributed throughout the attic and their superiority to the heavier materials increased with increasing distances from the point of discharge.