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Srivilliputtur, India

Sharma S.P.,Research Extension Center
Indian Silk

Stink bug is a known predator of tasar silkworm in early instars. But, it turns out to be bio-control agent of tasar against leaf gall. The author dwelling upon the issue, suggests to cash on this potential and use it as a bio-control agent to protect tasar silkworm. Source

Sakthivel N.,Research Extension Center
Indian Journal of Sericulture

The comparative efficacy of Dichlorvos and dimethoate solely and in combination with neem oil and fish oil rosin soap (FORS) against spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) and papaya mealybug, Paracoccus marginatus Williams Granara de Willink (Hemiptera: Pseudococcidae) infesting tapioca (Manihot esculenta Crantz), the food plant of eri silkworm (Sarnia cynthia r/c/u/Boisduval) was assessed under field condition. The synergistic effect of dimethoate (0.05%) with neem oil (3%) as well as FORS (2%) have been found equally promising with highest reduction in population of spiralling whitefly (85.37 & 85.14%) and papaya mealybug (81.00 & 80.10%) than its sole application (76.18 & 70.16%) and when compared to the respective treatments of dichlorvos against spiralling whitefly (78.17 & 73.58 and 64.91%) and papaya mealybug (69.35 & 66.88% and 52.49%). These combinations also recorded highest leaf yield i.e. 669.73 & 672.16 g/plant and 655.94 & 657.27 g/plant in the plots treated against spiralling whitefly and papaya mealybug respectively than other treatments, over control (515.30 & 478.63 g/plant) and may be used to manage both the pests successfully in tapioca garden. Source

Himantharaj M.T.,Research Extension Center | Vindhya G.S.,Central Scricultural Research and Training Institute
Indian Journal of Sericulture

Mulberry leaf is the exclusive food for the silkworm, Bombyx mori. The growth and development as well as the quality of cocoons are largely dependent on the nutritional status of the mulberry leaves (Bhuyian, 1981; Ito and Arai., 1963). Mulberry leaf quality is influenced by factors like variety, climate, fertilizers, water management and cultural practices (Krishnaswami et al., 1970). Ë number of practices are employed to assess the quality of mulberry leaves. These include thickness, weight per unit leaf area, stiffness, specific gravity as well as percentage of intercellular cell sap and its concentration (Mallikarjuna et al., 2000). Also, the'leaf quality can be evaluated by chemo assay and bioassay (Yoshida, 1955). Assessment of leaf quality through bioassay, considering silkworm rearing performance and cocoon quality as yardsticks, is understood to be one of the straight and accurate methods. However, the method is laborious, time consuming and difficult to conduct full rearing if a large number of varieties or treatments are to be evaluated. In India, to tide over this problem, moulting test is adopted to shortlist the mulberry varieties or treatments (Benchamin and Anantha Raman, 1989; Bongale and Chaluvachari, 1993). In sericulturally advanced countries, different methods viz., fasting test in China (Takeuchi; 1961; Ting Zingetal, 1994) and Keburui test in Japan (Anonymous, 1997) are employed for understanding the mulberry leaf quality. As these tests have so for not been tried in India, attempts have been made in the present study to document the efficacy of Keburui test as an alternative to the conventional moulting test for understanding the quality of the mulberry leaves. Source

Sakthivel N.,Research Extension Center | Qadri S.M.H.,Central Sericultural Research and Training Institute
Indian Journal of Sericulture

The jaggery solution and soya flour were supplemented with senescent tapioca leaves at different dosages and fed to eri silkworm,Samia cynthia ricini Boisduval during fifth instar and their effect on the economic traits was studied. The important economic parameters such as ERR %, cocoon yield (kg/100 dfls), shell yield (kg/100 dfls) and SR(%) of eri silkworm reared on senescent tapioca leaves were drastically reduced (46.24,21.214, 1.824 & 8.60) compared to the normal matured leaf (96.77, 74.105, 11.287 & 15.23). Fortification of the senescent leaf with jaggery solution and soya powder exhibited significant improvement in all treatment. However, maximum enhancement (72.94, 44.849, 5.650 & 12.60) was observed when the leaves were supplemented with 10% jaggery solution + soya powder @ 10g/100g leaves followed by 10% jaggery solution + soya powder @ 5g/ 100g leaves (70.37,43.329, 4.641 & 10.71). Source

Shoot cum bunch feeding method of tapioca leaves registered significantly highest cocoon yield, shell yield and silk ratio of eri silkworm, Samia cynthia ricini Boisduval in summer, rainy and winter seasons. The next best method was shoot feeding followed by leaf cum bunch feeding and bunch feeding. Leaf feeding method was recorded least except that of winter season in which it was on par with bunch feeding. Source

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