Cellular Moth Examination: A Paradigm Shift in Oak Tasar Grainage Activity

Abstract

In India during some past years, the oak tasar cocoon production has drastically reduced due to certain disease in oak tasar silkworms, which has lead to significant mortality to the batches of oak tasar silkworms. The damage caused by this disease decreases cocoon crop production up to 80%. As the disease is transmitted through mother moth, it is very essential to avoid the transmission of disease during the grainage activities. The seed sector is backbone for the development of the silk industry. Quality of oak tasar seed and efficiency of grainage depend on the quality of the cocoons, selection of healthy seed cocoon, effective microscopic examination and production of healthy & quality Dfl's. Since long, many techniques have been identified to produce disease free layings (Dfls). Among them REC, Palampur preferred cellular moth examination technique (CMET) for the production of Dfl's. During the year 2016 to 2018, REC, Palampur used CMET by using small paper box of size lenght-3.5'', width-4.5'' and height-2.5'', in which single female moth was kept for oviposition. After the completion of oviposition, each moth was microscopically examined for identification of any infection such as bacteria, pebrine etc and in case of any infection, Dfl produced was rejected and destroyed instantly. Before the year 2016, mass oviposition was practiced, in which small nylon net was used to keep 10-15 moths together. This resulted to remarkable loss/ rejection of the Dfl's, leading to the reduction in Dfl's production. Pooled data of mass examination and cellular examination indicated that, cellular examination resulted with decrease in cocoon-Dfl ratio (from 13.64:1 to 4.36:1), decrease in rejection of Dfl's after microscopic examination (from 51.74% to 4.54%) and increasing trend in grainage from 48.26% to 95.21%. This trend clearly indicated that, cellular examination of egg layings is very much encouraging for production of oak tasar seeds and successful grainage activities.