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

Abstract

The 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. During young age (1st and 2 nd instars) rearing the tender leaf and  late age (3rd , 4 th and 5 th 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. The young age (1st and 2 nd instars) silkworms were fed with daily once (8 am), twice (8  am and 8 pm) and thrice (8 am, 2 pm and 9 pm).While late age (3rd , 4 th and 5 th instars) 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). 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 2 nd instars)) and matured wet  castor plant leaf daily thrice for late age (3rd , 4 th and 5 th 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 2 nd instars) and normal three times/day castor leaf feeding at late age was  inferior in larval, cocoon and silk traits.