Insecticidal Effect of Inert Solid Diluents

Publisher Website
Google Scholar
Abstract
Working from the known fact that the inert diluents in insecticide dust mixtures have an influence on the toxicity of the mixtures, a number of such diluents were tested on groups of 24-hr. old 3d and 4th instar Mexican bean beetle larvae, and rates of mortality observed. Most effective diluents were Barden clay and Attaclay, fuller''s earth and asbestine, Bancroft clay; least effective: EMTCO 23 Talc, Filtrol X-415, and Talc No. 6-J. There is no evidence that any diluent particles entered the bodies of the larvae, either orally or through the spiracles. Electron microscope photographs showed, contrary to expectation, that the unsuccessful diluents have sharp edges, whereas the successful appear much less abrasive. An absorptive action on the waxy layer of the exocuticle is postulated.
Keywords