The appropriate varieties of cassava for Eri silkworm rearing in the northeast

Abstract

Eri silkworm rearing experiment was undertaken at room temperature in 3 seasons (summer 31.1+2.5 oC, 59.4+8.1% RH; rainy 29.0+1.0 oC, 71.6+7.2% RH; cool 26.6+2.0 oC, 60.5+6.8% RH) using leaves of 9 cassava varieties, compared to castor. These cassava varieties were Rayong 2, 3, 5, 60, 72, CMR 14, 129, 5 Minute and KU 50. It revealed that the life cycles of silkworm fed with all tested host plants were similar in 3 seasons. The life cycle in cool season was longer than in summer – and rainy season. In summer – and rainy season, the shortest life cycle was obtained when fed with castor leaves of 54.67 and 54.33 days, respectively. Cassava Rayong 2 variety caused the longest life cycle of 56 days for both seasons but only in rainy season CMR 14 gave also the longest life cycle as Rayong 2. In cool season, Rayong 2 valued the longest life cycle of eri silkworm (59.34 days) and the Rayong 72 gave the shortest life cycle (57.33 days). On the consideration of yield components, castor was the best in summer. Cassava Rayong 72 was the best among cassava varieties. The average of total cocoon shell weights and total hatching eggs obtained from feeding of Rayong 72 were 9.75 g and 3,659.50 eggs, respectively. In rainy season, castor was a suitable host plant similar to summer. Among cassava varieties, the Rayong 72 and 5 Minute varieties were the most proper to feed in rainy giving average total cocoon shell weights 11.58 g and 11.51 g, and total hatching eggs of 4,429.07 and 3,376.67 eggs, respectively. In cool season, the cassava 5 Minute was the most suitable as host plant, expressed average of survival percentage, total cocoon shell weight and total hatching eggs as 95.56%, 9.38 g and 4,015.51 eggs, respectively. Rayong 2 was the least proper host plant in 3 seasons. The cocoon shells obtained from feeding with different host plants were produced for yarn by hand reeling and spinning using traditional spinning wheel. The result shows that there is no significance in time producing, yarn weight and length (P>0.05).