Studies on Nursery Raising, Pests and Culturing Eri Silkworm (Samia cynthia ricini Boisdual) on Flemigia semialata Roxb.
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Date
2017-12
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University of Agricultural Science, Dharwad
Abstract
Studies on nursery raising, pests and culturing eri silkworm on Flemingia semialata Roxb. were carried out at Ericulture laboratory, Department of Agricultural Entomology, UAS, Dharwad during, 2015-16. The study on nursery raising with different pre-sowing seed treatments of F. semialata revealed that seed germination parameters were higher on treating seeds with concentrated H2SO4 viz., germination, shoot length, root length, number of roots, number of leaves and seedling vigour index (75.00 %, 11.15 cm, 8.65 cm, 13.96, 9.08 and 1482 respectively) when compared to other treatments. With respect to stem cuttings, treatment with IBA @ 2000 ppm on hardwood cuttings gave significantly higher results viz. sprouting, establishment and seedling vigour index (46.67 %, 33.33 % and 1718 respectively) than other treatments.
About twenty three insect-species were recorded during the study period (Jun to Feb, 2015-16) on F. semialata plants. Among the different orders observed, Lepidoptera was the dominant group comprising ten insects. Nine insects belonged to Hemiptera and one each to Coleoptera, Orthoptera, Isoptera and Diptera. Major insects causing significant damage were pigeonpea pod fly (88.65 %), mealy bug (22.28 %) and spiraling white fly (18.43 %).
Culturing eri silkworm revealed that among the host plants tried for eri silkworm rearing high survival rate (97.03 %), larval weight (7.10 g), silk gland weight (0.54 g), higher shell percentage (13.87 %), ERR (96.52 %), short larval duration (19.96 days) and short life cycle (45.96 days) were observed when reared on castor. Within Flemingia treatments high survival rate (67.18 %), larval weight (4.68 g), silk gland weight (0.41 g), ERR (42.87 %), short larval duration (40.95 days) and short life cycle (66.89 days) was observed when reared on tender leaves upto 3rd instar and medium mature leaves in 4th and 5th instar.