National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Native isolates of EPNs, Heterorhabditis bacteriophora and Oscheius chongmingensis were isolated from the tea plantation crop of Jorhat district of Assam and were tested against tea mosquito bug Helopeltis theivora andbunch caterpillar, Andraca bipunctata through mortality test under laboratory condition. For that 5, 10, 50, 100,150, 200 and 250 infective juveniles of each isolate were inoculated per insect. The insect mortality was observed after 24, 48, 72 and 96h exposure. It was observed that 50, 60 and 70 per cent mortality of H. theivora were recorded by H. bacteriophora (150 IJs/insect) at 48 h, 72h and 96h of exposure. It recorded that with the increase in the exposure period to 96 h, H. bacteriophora could induce up to 90% mortality of the tested insect at the dose of 250 IJs. Similarly, mortality of H.theivora increased with increase in the dosage of O.chongmingensis and recorded 50, 60 and 70 per cent mortality at 200 IJs/insect at 48 h, 72 h and 96h. Bioassay of H. bacteriophora and O. chongmingensis against the 3rd instar larvae of A. Bipunctata indicated that at 250IJs/larva recorded 70 and 60% mortality in 48 hours of exposure, while 100 and 90% mortality of A. bipunctatawas recorded at 96h.However, in the present investigation, probit analysis revealed that H. bacteriophora showed maximum mortality than O. chongmingensis against H. theivora and A. bipunctata at 48 h,72 h and 96h of exposure time.
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