Insecticidal Dusts for the Protection of Stored Peas and Beans against Bruchid Infestation

Abstract

Laboratory tests are described for determining the protective value of a number of physically and chemically active insecticidal dusts against Bruchid infestation of peas and beans. Acanthoscelides obtectus (Say) and Callosobruchus chinensis (L.) were used as the test insects and were found to be very susceptible to most of the treatments tried. Adults of A. obtectus were in general more resistant to the treatments than those of C. chinensis, but the multiplication of the former species was more easily stopped, apparently because of the vulnerability of its first-stage larvae. It is concluded that protection of peas and beans can be achieved by thoroughly mixing into 200 lb. of the commodity 6–8 oz. of one of the following dusts: colloidal silica, colloidal aluminium pentasilicate, finely ground diatomite, 0.05 per cent. y BHC (as lindane) on diatomite or kaolin, 0.5 per cent. technical DDT on diatomite or kaolin. Rock phosphate, kaolin, or talc are not recommended. Where lindane or DDT are used in the dosages given, it is unlikely that the commodity will be tainted or rendered toxic to man or animals, even if no cleaning is undertaken.