Management of Helicoverpa armigera with Nuclear Polyhedrosis Virus on Cotton Using Different Spray Equipment and Adjuvants

Results of a field experiment on the control of Helicoverpa armigera Hbn. on cotton with nuclear polyhedrosis virus (NPV) at a dose of 3×10¹² polyhedral occlusion bodies/ha using different spray equipment revealed that significant control of the pest and its damage to squares and bolls could be achieved in an the treatments. Seed cotton yields in plots sprayed with the virus by all the three spray equipment were significantly higher than in control and the difference between the treatments were not significant showing that for the control of H. armigera on cotton with NPV, anyone of the spray equipment can be used. In another experiment which evaluated the efficacy of NPV applied with certain adjuvants by a mist blower, it was found that a combination of NPV with cotton seed kernel extract (2.5 kg/ha) and crude sugar (2.5 kg/ha) recorded significantly lower boll damage than NPV applied alone. The seed cotton yield in the different treatments as well as in the control however did not differ significantly.