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INVESTIGATIONS OF RESIDUAL ACTIVITY, TOXICITY, AND SORPTION OF CHLORPYRIFOS FORMULATIONS (KILLMASTER (REGISTERED TRADEMARK) AND DURSBAN (REGISTERED TRADEMARK)
Abstract
The potential use of a plastic resin lacquer (Killmaster('(REGTM))) to extend the residual activity of agricultural insecticides was investigated. Greenhouse tests indicated that the lacquer could be applied at manufacturer's recommended rates to various plant species without the production of phytotoxic symptoms. Field tests for control of corn rootworm larvae (Diabrotica spp.) and grasshoppers (Melanoplus spp.) revealed no significant differences in efficacy between insecticides emulsified with or without the lacquer. The possibility that emulsification disassociated the insecticide from the lacquer was investigated and discounted. Laboratory experiments with an insecticide-susceptible strain of German cockroaches, Blattella germanica, demonstrated no advantage for a lacquer formulation of chlorpyrifos as compared to an emulsifiable concentrate formulation in terms of topical toxicity and residual efficacy after one year. Additional laboratory tests showed the layer "integrity" of initial insecticidal-lacquer applications was not maintained when additional applications were made to painted wood surfaces. Lacquer did provide protection against desorption of chlorpyrifos by water from a treated surface. No practical advantage was demonstrated in the tests for the lacquer formulations over the conventional emulsifiable concentrates for any insecticide tested. Residual activities of various combinations of application rates and times were evaluated with ('14)C-chlorpyrifos labeled Dursban using susceptible German cockroaches. A standard procedure that utilized an initial application of 0.5% active ingredient (AI) Dursban and subsequent monthly applications of 0.25% AI Dursban was shown to produce insufficient availability of chlorpyrifos between treatments to provide acceptable control of German cockroaches under laboratory conditions. A theory was proposed to explain measured levels of chlorpyrifos under different treatment combinations. Evaluations of tissues from American cockroaches, Periplaneta americana, for ('14)C-chlorpyrifos revealed that: (1) chlorpyrifos and/or its labeled metabolite(s) concentrated in the gut tissues and malpighian tubules; (2) no measurable accumulation occurred in the brain samples; (3) approximately 31% of the ('14)C detected in the cockroaches was contained in the haemolymph; and (4) labeled material was translocated in the haemolymph.
Subject Area
Entomology
Recommended Citation
MILLER, TIMOTHY PATRICK, "INVESTIGATIONS OF RESIDUAL ACTIVITY, TOXICITY, AND SORPTION OF CHLORPYRIFOS FORMULATIONS (KILLMASTER (REGISTERED TRADEMARK) AND DURSBAN (REGISTERED TRADEMARK)" (1982). ETD collection for University of Nebraska-Lincoln. AAI8217546.
https://digitalcommons.unl.edu/dissertations/AAI8217546