Bio-ecology and Management of Cotton Bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Studies were carried out to evaluate the seasonal incidence of population of Helicoverpa armigera, Chrysoperla carnea and parasitism of H. armigera by Habrobracon hebetor in three districts, i.e. Faisalabad, Multan and Rahim Yaar Khan, temperature dependent biological parameters, drought influence on H. armigera along its natural enemies [C. carnea (Stephens) and H. hebetor (Say)] and development of IPM module against H. armigera in cotton agro-ecosystem. The maximum population of adults and larvae of H. armigera recorded during the month of August was 4.10 per trap and 0.52 per plant, respectively. The lowest population was recorded in October, with values of 0.87 adults per trap and 0.12 larvae per plant. Population of C. carnea was highest (0.90 per plant) in September and the lowest number (0.21 per plant) was recorded in July. Similarly, parasitism rates were highest (33.7%) and lowest (04.87%) in September and July, respectively. Adults and larvae of H. armigera were highest in R.Y. Khan i.e. 3.48 and 0.44 per plant, respectively. In contrast, C. carnea population was highest (0.72 per plant) in Faisalabad which was followed by Multan (0.55 per plant) and R.Y. Khan (0.38 per plant). Parasitism was also high in the district Faisalabad (13.39%) followed by Multan (6.36%) and R. Y. Khan (6.23%). Adults and larvae were positively correlated with temperature and r values were calculated at 0.5818 and 0.5240, respectively. Population of C. carnea was negatively correlated with temperature with an r value of -0.5546. Similarly, the parasitism of H. armigera by H. hebetor was negatively correlated with temperature (r= -0.5768). Higher temperatures decreased the duration of development and also decreased the reproductive capacity of H. armigera, C. carnea and H. hebetor. Degree days for developmental period for H. armigera, C. carnea and H. hebetor were 250, 166.67 and 71.43, respectively. The drought caused significant detrimental effects on population of H. armigera and parasitism by H. hebetor. In contrast, C. carnea population was not significantly (F= 2.01, DF= 4 and P>0.05) affected by drought. The maximum yield was recorded 1639.52 kg/ha (16.0 kg/plot) in T15 [T1 (spray of Spinosad) + T2 (spray of neem seed kernel extract) + T3 (release of C. carnea) + T4 (release of H. hebetor)] which was followed by T12 [T1 (spray of Spinosad) + T2 (spray of neem seed kernel extract) + T4 (releases of H. hebetor)] and T13 [T1 (spray of Spinosad) + T3 (release of C. carnea) + T4 (release of H. hebeor)] with values of 1475.568 and 1332.11 kg/ha, respectively. T1 (spray of Spinosad), T5 [(spray of Spinosad) + (spray of neem seed kernel extract)] and T15 proved the most economical pest management modules exhibiting CBR 1:6 followed by T7 [(sprays of Spinosad) + (releases of H. hebetor)] and T12 [(spray of Spinosad) + (spray of neem seed kernel extract) + (releases of H. hebetor)] which explained a CBR of 1:5.5 approximately.