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Subject: Nematology × Author: Babita Kumari × Start date: 1997 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Studies on the efficacy of native strains of entomopathogenic nematodes in the management of insect-pests of cauliflower
    (Chaudhary Charan Singh Haryana Agricultural University hisar, 2022-11) Babita Kumari; Anil Kumar
    Out of 280 soil samples collected from different localities, 83 samples contained EPNs with 29.6 per cent frequency of occurrence. Six isolate (strains) viz., HAR-St-I, HAR-St-II, HAR-St-III, HAR-Ht-I, HAR-Ht-II and HAR-Ht-III were selected from the EPNs isolated. On the basis of morphological, morphometric and molecular characterization, these isolates were identified as Metarhabditis amsactae. Efficacy of these strains of M. amsactae were tested against Pieris brassicae, Spodoptera litura and Plusia orichalcea under laboratory condition, at four inoculum levels i.e. 05, 10, 20 and 40 IJs /insect larva. In both strains (HAR-St-II and HAR-Ht-III), as the observation time and level of IJs increased, there was a significant increase in per cent mortality of all three insects. Recovery of M. amsactae was less from cadaver of Plusia orichalcea than Pieris brassicae and Spodoptera litura.In Wout’s medium-I, multiplication of strain HAR-St-II was more than strain HAR-Ht-III, both after 30 and 60 days. Multiplication of both strains of M. amsactae was higher after 30 days than after 60 days. Among cadaver based formulation, alginate gel, foam chips, clay chips and water dispersible granules, cadaver based formulation was found to be best. Maximum numbers of active IJs after 90 days were obtained from this formulation were 3370 and 2728 /Petri plate in strains HAR-St-II and HAR- Ht-III, respectively. In 25, 50, 75 and 100 μm nozzles, 100 μm nozzle gave maximum larval mortality of S. litura, and mortality increased with increase in size of nozzle and period of observation. Two sprays of both strains proved better than single spray, but it was less effective than Malathion 50 EC @ 400 ml/acre to control insect-pests of cauliflower.