Efficacy of food-grade diatomaceous earth as grain protection against Rhyzopertha dominica -Lesser Grain Borer in stored chickpea under tropical conditions

Abstract

The efficacy of different concentrations of diatomaceous earth against the Rhyzopertha dominica in chickpea was evaluated. The selected concentrations were 0.01%, 0.05%, 0.1%, 0.5%, and 1% on (W/W) basis. Each treatment was replicated three times and 20 same-aged unsexed adult Rhyzopertha dominica species were introduced into each jar. The percentage of mortality Rhyzopertha dominica species and weight reduction of chickpea commodity were recorded weekly for five weeks. After the 5th week onwards the samples were let to progeny development without any disturbance. The progeny counts were carried out at the end of the 9th week. The results showed that mortality percentage Rhyzopertha dominica species, weight reduction of chickpea commodity, and progeny emergence highly affected by different concentrations of diatomaceous earth (DE). The maximum percentage of mortality was attained early, when the concentration was 1%, at the end of the 3rd week (100%). The percentage of weight reduction is relatively less for 1% concentration compared with other treatments. After 9 weeks of exposure, the chickpea commodity treated with 1% and 0.5% concentrations of DE shows the zero number of visible pupal stage and F1 adult progeny of Rhyzopertha dominica species. While chickpea commodity treated with 0.1% concentration of DE shows the dead visible F1 generation of Rhyzopertha dominica species. This means, the larva has emerged as adults but at the end of the 9 weeks of the exposure period, F1 progenies were completely suppressed. The percentage of mortality Rhyzopertha dominica species, weight reduction of chickpea commodity, and the emergence of the progeny of Rhyzopertha dominica species depend upon the different concentrations of DE and applying 1% of DE highly effective concentration to control the Rhyzopertha dominica species in the chickpea commodity.