Efficacy of different doses of phosphine against Tribolium castaneum (Herbst.) in stored rice

Abstract

Rice is an important and staple cereal food in India after wheat. When rice grains are stored under bulk conditions and larger quantities, it is being damaged by several insect pests. Among different insects infesting stored rice grains, the red flour beetle, Tribolium castaneum cause significant damage as secondary storage pest. Studies were conducted on the efficacy of two different doses of phosphine such as 2 gram per MT and 3 gram per MT (metric tonne) in food grain warehouse. The results revealed that the highest concentration of phosphine was recorded on the 3rd day of fumigation and concentrations were decreased thereafter in both the dosages. It was observed that that the lower dosage 2 gram per MT was also effectively killed the adults of T. castaneum significantly as that of 3 gram per MT dosage and there were no post fumigation emergence of the pest in bioassay samples in both the dosages. By following proper fumigation procedure especially complete sealing of enclosure, the existing dosage of 3 gram per MT will work effectively in killing the stored pests in large food grain warehouses.