Evaluation of different plastic packing materials and food substrates on efficacy of phosphine fumigation against larvae of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Trogoderma granarium (Everts) (Coleoptera: Dermestidae)

Abstract

Plastic packaging provides a barrier to insects and micro-organisms from getting access to food besides maintaining the internal temperature. In order to see the effect of different packing materials and food substrates on efficacy of phosphine fumigation against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Trogoderma granarium (Everts) (Coleoptera: Dermestidae), an experiment was conducted at the Entomological Laboratory of the University College of Agriculture and Environmental Sciences, The Islamia university of Bahawalpur. Insects were reared on natural diet at optimum conditions of 30±2 ºC and 65±5 % relative humidity. Three packing materials i.e. polyethylene, polypropylene, polyvinylchloride and four food substrates were used i.e. wheat flour, rice flour, corn flour and oat flour for T. castaneum while wheat, rice, mung bean and black gram for T. granarium. The effect of different packing materials on percent mortality of T. castaneum and T. granarium was significant at 24 and 48 hours after the treatment while the effect of food substrates on percent mortality was significant at 24 hours for T. castaneum and 48 hours for T. granarium. The maximum percent mortalities of 83% and 98% were recorded in T. castaneum at 24 and 48 hours in all the food substrates packed in polyethylene and polypropylene. Similarly, the maximum percent mortalities of 55% and 88% were recorded in T. granarium at 24 and 48 hours in all the food substrates packed in polyethylene and polypropylene.  It was concluded that polyethylene and polypropylene are the most suitable packing materials for various food substrates in order to control T. castaneum and T. granarium.