Effect of Wet Castor Leaf Feeding and Feeding Frequencies on Economic Traits of Eri-Silkworm, Samia cynthia ricini Boisduval (Saturnidae: Lepidoptera)

Abstract

This study was carried out at Melkassa Agricultural Research Center in the sericulture and apiculture research laboratory during 2012 and 2013G.C. cropping seasons. Both tender and matured castor leafs were obtained from Melkassa Agricultural Research Center, sericulture research field to investigate the effects on castor feeding silkworms. The treatments consist of young and late age rearing of silkworm. During young age (1st and 2nd instars) rearing, the tender leaf and late age (3rd, 4th and 5th instars) rearing, matured castor leaf were dipped in the water and excess water was drained out by shaking and fed to the silkworms as per the treatments. Feeding the 1st and 2nd instars silkworms (young age) with daily once (8 am), twice (8 am and 8 pm) and thrice (8 am, 2 pm and 9 pm) with tender wet leaf. While at late age (3rd, 4th and 5th instars) the silkworms were fed with daily twice (8 am & 8pm), thrice (8am, 2pm and 8 pm) and four times (8am, 12 noon 4 pm and 9 pm) with matured castor leaf. The control batch silkworms were reared as per the standard rearing practices. The experiment was laid out in a randomized block design in three replications with a disease free laying per replication. Rearing of castor feeding silkworm by giving tender wet leaf daily twice at young age (1st and 2nd instars)) and matured wet castor plant leaf daily thrice for late age (3rd, 4th and 5th instars) silkworm significantly reduced the larval duration and diseases incidences and improved all the larval, cocoon and silk traits as compared to other feeding frequencies. While, the recommended normal three times/day castor leaf feeding at young age (1st and 2nd instars) and normal three times/day castor leaf feeding at late age was inferior in larval, cocoon and silk traits.