Bücher von A V Khanpara

The adults were yellowish green in colour, wedge shaped and walked diagonally in a characteristic manner. The nymphal stage passed through five instars. The female inserted eggs into leaf tissue. The total duration of life cycle was 18 to 30 days in case of male, while it was 20 to 34 days in case of female at an average temperature of 31.30 ± 1.96° C and the relative humidity of 73.96 ± 3.02 per cent. The genotypes / varieties GG-5 and GG-2 were found least susceptible to jassid. Two type of predators viz., Chrysoperla carnea (Stephens) and Crossopalpus sp. were found in the field. The treatments monocrotophos 0.04 per cent, methyl-o- demeton 0.025 per cent and dimethoate 0.03 per cent were found most effective for the control of jassid under field conditions. Considering the yield and economics, two sprays of monocrotophos 0.04 per cent gave maximum yield of groundnut pod and haulm (2014 kg/ha and 2812 kg/ha) and the highest cost benefit ratio of 1:19.85 followed by methyl-o-demeton 0.025 per cent (1910 kg/ha and 2622 kg/ha) (1:17.94) and dimethoate 0.03 per cent (1806 kg/ha and 2413 kg/ha) (1:18.27).

Among various insect-pests attacking pigeonpea, H. armigera (Hübner) Hardwick is a cosmopolitan and highly polyphagous insect and is the major biotic constraint. In Asia, H. armigera has developed high levels of resistance to organochlorine, organophosphates and synthetic pyrethroids. The trends also highlight the need for safe and effective management strategies for H. armigera, given impetus to the development and use of alternative and has less negative impact on beneficial organisms than conventional insecticides. At present, alternative is the biopesticides for its eco-friendly management. The effectiveness and economics of different treatments Bt @ 1.0 kg/ha and Bb @ 1.5 kg/ha along with half dose of endosulfan 0.035 per cent per cent were found as effective as the recommended synthetic insecticides for the eco-friendly management. The persistence of B. thuringiensis @ 2.0 kg/ha and B. bassiana @ 3.0 kg/ha became half within 3 days and caused the mortality in H. armigera larvae up to 7 and 11 days, respectively. Both the application methods (spraying and irrigation) of Bb proved to be equally effective in affecting the post-development of Helicoverpa larvae.