Insects subsequently emerging were counted to estimate F1 progeny production. Counting was stopped after 35 days to avoid overlapping of generation .Weight loss was calculated as the difference between the final and initial weights of treated or untreated grain, corrected for changes in moisture content, and expressed as a percentage of
initial weight of grains. The following equation was used:
% WL= (IW-FW) X 100 / IW
Where, WL: Weight loss index.
IW: Initial weight and FW is the final weight. Mean of all determination (+SEM) were recorded. Statistical analysis
The experiment was carried out by adopting analysis of variance one way classification and the data thus collected were statistically analysed by using SPSS software in a microcomputer. The F-values and Critical Difference was calculated from the ANOV A table of analysis of variance.