Virulence Determination Nuclear Polyhedrosis Virus on Cotton Bollworm Helicoverpa armigera and Diamond Back Moth, Plutella xylostella

Nucleopolyhedro virus (NPV) has an important role in pest management programs. Because of many advantages such as selective effect on larvae of insect pest, no undesirable effects on environment and non-target organisms and also compatibility with other pest management tactics. In this research, the virulence of a native isolate was evaluated on the larvae of cotton bollworm, Helicoverpa armigera Hübner and diamond back moth, Plutella xylostella at 27±2 oC, 65±5% RH and 16L: 8D photoperiod. Based on the results, 50% lethal concentration (LC50) of virus on the 2nd larval instars of H. armigera and P. xylostella were determined as 9.2×103 OB/ ml -1and 3.8×104 OB/ml -1, respectively. Also results (LC50 – values), showed that NPV was more virulent on H. armigera than on the P. xylostella. Values obtained for 50% lethal time (LT50) of NPV were almost similar 5 and 4.8 days post treatment for H. armigera and P. xylostella, respectively.