STUDIES ON Development OF RESISTANCE TO PHOSPHINE AND CARBON DIOXIDE IN SOME STORED.PRODUCTS PESTS

Abstract

The ma111 objective of the present work was to study the development of re istance in two mite species inte ting stored products, namely, the grain and flour mites Aleuroglyphus ovatus, Troupeau and Tyrophagus putrescentiae (Schrank), to1:phosphine, carbon dioxide and their mixtures, in comparison wit!one of the pulse insects, namely Callosobruchus maculatus (Fab.).! I Also some biological characteristics of the obtained resistant strains of C. macula/us were investigated in the laboratdry.

This Department, University .

1 I study was . performed at the Plant &rotection I Faculty of Agriculture at Moshtohor,l Zagazig

. . I The obtained results are summerarized under the following topics:- \

1. Development of resistance in the two mite specois (. ovatus and T. putrescentiae) to pllosphine:- . • \ . I Adult populations of the two mite species A. ova:tus and T. putrescentiae were exposed in the laboratory for 17 gen rations.to a fixed concentration of phosphine (200 vpm) at 26+ 1 C, 85 5% RH at varying exposure periods in order to select strains resistant

to Pl-13 .

• • I • I

Selection pressure was carried out at the median l thaidose (LC.Tso) inducing • mortalities between 50-70o/ . The . susceptibility of the achieved strains was compared with the parent strain. I

Results showed that the lethal times needed forla certain . I mortality w re somewhat longer ,in the 17th g neratioln of A. ovatus and 7. putrescentzae, than of the parent strams. I