Storable ready to use bait formulation for the control of Spodoptera litura F. with increased insecticidal activity

Abstract

The extensive problems by Spodoptera litura F. a polyphagous pest pointing the necessity of management tactics integration to minimise resistance development and effective control. This study aimed to standardise the storable ready to use bait formulations incorporating both Nucleopolyhedrovirus and botanical oils, neem and pongam oil, and evaluate their efficacy under laboratory and polyhouse conditions. A laboratory bioassay with serial dilutions of the SlNPV 105 to 1010 OBs/ml was used to assess the virulence of the virus and showed increased mortality with increased concentration. The results of the free-choice and no-choice studies revealed that the artificial diet recorded the highest attraction (13.33 to 33.33%) at 12-hrs after release followed by wheat bran (65%) + wheat flour (35%) + additives (26.67%) and wheat flour (75%) + chickpea flour (25%) (20.00%). Among the five combinations tested, a combination of wheat flour and an artificial diet exhibited the greatest attraction and consumption at 12 hours after release. The storable rehydratable bait formulations, wheat bran (65) + wheat Flour (35) + additives + SlNPV (107) + Pongum oil (3.0%) and wheat bran (65) + wheat Flour (35) + additives + SlNPV (107) + neem oil (2.5%) recorded more larval death of 100% and 93.33% respectively in laboratory bioassays from 6 days after treatment. The highest mortality of S. litura larvae was recorded in the treatments with a combination of baits followed by SlNPV spray compared to their single application. The prospective impact of storable baits infused with SlNPV and botanical oils on larval mortality ranges from 96.67% for bait containing pongam oil to 90.00% for bait containing neem oil, subsequently succeeded by the application of NPV.