Insecticidal properties of actinobacterial extracts against selected lepidopteraninsect pests under laboratory and greenhouse condition

Abstract

Microbial pesticides have evolved as an alternate technique to chemical insecticides due to their high targetspecificity and ecological safety. Investigations were carried out to explore the efficacy of 28 actinobacterial extracts againsta day old second instar larvae of Plutella xylostella, Spodoptera litura and Spodoptera frugiperda. Among the actinobacterialextracts, DBT-64 recorded 78.85, 76.50 and 76.00 per cent mortality of P. xylostella, S. litura and S. frugiperda respectivelyfollowed by DBT-80 with 80.75, 75.25 and 77.50 per cent mortality. Further, DBT-59 has recorded 79.50, 78.25 and 75.25per cent larval mortality of P. xylostella, S. litura and S. frugiperda respectively at 72 HAT under in-vitro conditions. Amongthe actinobacterial extracts, three potent extracts (DBT-64, DBT-80 and DBT-59) were taken forward to greenhouseconditions to test verify their efficacy against P. xylostella, S. litura and S. frugiperda. DBT-80 has caused highest larvalmortality in P. xylostella (84%), S. litura (82.75%) and S. frugiperda (80.50%) followed by DBT-64 with 81.00, 80.00 and79.50 per cent larval mortality in P. xylostella, S. litura and S. frugiperda respectively at 96 HAT under green housecondition. Among the isolates, DBT-80 showed higher insecticidal activity against the test insects followed by DBT-64 andDBT-59. These potential actinobacterial extracts can be used in the Integrated Pest Management programmes of Plutellaxylostella, Spodoptera litura and Spodoptera frugiperda which are found very effective under laboratory and greenhousecondition.