Document Type : Original research papers
Authors
1
Plant Protection Dept. Fac. of Agric. Damietta Univ., Egypt
2
Economic Entomology Department, Faculty of Agriculture, Mansoura University
3
Plant protection, Agriculture, Damietta University, Damietta, Egypt
4
Faculty of Agriculture, Omar El-Mokhtar University, Libya
5
Plant Protection Department, Faculty of Agriculture, Damietta University
Abstract
The khapra beetle, Trogoderma granarium (Coleoptera: Dermestidae) is a cosmopolitan species and one of the most destructive insect pests of stored grain products, and dozens of other commodities, with great importance. Temperature is a major driver of key insect functions, involving development, survival, longevity, and reproduction. Therefore, this work designed to study effect of different temperature regimes (22°, 27°, 32°, 37º, and 42ºC) on development, reproduction, longevity and grain weight loss of T. granarium using the whole wheat grains as a feeding substrate. The developmental time and rate were used to estimate the lower developmental threshold (T0) and then the degree-days (dd's) required to compete development. Temperature had significant effects on total development, longevity, life span, fecundity, and weight loss of T. granarium. Except at 42°C, the survival rates of immature stages increased as the temperature increased. As well, sex ratio biased for females as temperature increased from 22º to 37ºC, but at 42ºC the sex ratio biased for males. The lowest T0 was recorded for male's life span, followed by that for female's life span. On average, the total life cycle, and female and male life spans of T. granarium beetles needed 602.0 ± 15.08, 938.14 ± 31.86, and 950.23 ± 22.34 dd's, respectively to complete their development. This study recommends the wholesalers to use temperature of 42ºC or above to protect stored wheat, since it increased mortality rates, reduced fecundity and longevity, and minimized wheat weight loss by T. granarium.
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