ANTIXENOTIC & ANTIBIOTIC IMPACT OF BOTANICALS FOR ORGANIC MANAGEMENT OF STORED WHEAT PEST INSECTS

Abstract

Present study was planned to utilize the indigenous organic resources for the insect pest management of stored wheat with the purpose to provide safe food to the end users and to make the pest control technique environment-friendly. It will also be helpful to avoid heavy expenses being spent on the import of pesticides. The focus of the project was to provide a secure IPM protocol to the farmers for the easy and organic control of stored grains insect pests, at farm level. For this purpose, oils of Acorus calamus (Sweet flag), Azadirachta indica (Neem) and Ricinus communis (Castor) were applied individually and as combinations in various concentrations @ 15-18 ml solution per sq. ft. area of the jute/cotton bags of different densities. Infestation free wheat was packed in respective treated bags and stored under prevailing ambient conditions of the flourmills. Antixenotic and antibiotic effects of the botanical oils were determined at different storage intervals i.e. 30, 60 and 90 days against Rhizopertha dominica, Sitophilus granarius, Tribolium castaneum and Trogoderma granarium. Statistical examination of the data regarding percent mortality and population build up of the target insects has indicated that different concentrations, storage periods and packing materials have a momentous effect on the insects mortality and their penetration into the bags. Degree of antixenosis and antibiosis has a linear correlation with the concentration of the oils but inversely with the storage periods. Moreover, penetration into the bags was inversely but the mortality was directly proportional to the density of the packing materials. It was observed that fine packing material with 20% concentration, Neem oil conferred 90 %, sweet flag oil 94% and castor oil 82% mortality up to one month. Afterwards a gradient decrease in percent mortality was found in second and third months. Whereas, mixture of three oils in 10% concentration of each exhibited 100, 95.55, and 91.55% mortality for 30, 60 and 90 days respectively, in cotton bags, having mesh size of 0.1 x 0.1 mm. Farinographic studies indicated non significant differences on the water absorption of the dough made from the respective flours of the treatments and the control. Furthermore, sensory evaluation established that there was no distinguishable taste or taint found in the chapatties made from the respective flours of the treatments and the control. It is concluded that oils of Acorus calamus, Azadirachta indica and Ricinus communis are effective, with the selected dosage levels, to save the stored grains from insect pests, the food from toxic residues and the environment from chemical pollution. Mixture of three oils in 10% concentration showed a better performance than the rest of treatments. Therefore, packing of the cleaned wheat in new treated bags with selected botanical oils and proper sealing thereof can, certainly, provide better results for the safe storage of food grains. An addition of some appropriate IPM practices may also be a supplement for the accomplishment of the suggested insect pests control measure.