Department of Entomology, Punjab Agricultural University, Ludhiana-141 004, Punjab, India.
Optical brighteners when used with baculoviruses have improved their field performance against insect-pests in most agricultural ecosystems. The co-toxicity factors as well as various interaction-responses between the HearNPV (PAU-1 strain) @ 6 × 106 OBs/ml and two selected optical brighteners (‘Ranipal’ and ‘Ujala’, each at 0.5 and 1% concentration) were worked out by feeding these entities through tomato leaves cv. Punjab Chhauhara to Helicoverpa armigera (Hübner) larvae (1.84 ± 0.29 cm). Feeding virus with ‘Ranipal’ (1%) produced acute-virosis induced cent per cent larval mortality within 8-days post treatment (DPT) periods, yet was also at par with ‘Ujala’ (1%) causing 96.8 per cent similar larval death, in contrast to 48.3 per cent larval death in virus alone within 8-DPT, as well as nil mortality among both the optical brighteners at both the tested concentrations. The calculated co-toxicity factors indicated that two optical brightnes can be used to enhance the performance of HearNPV against H. armigera on tomato crop.
