Vol. 9 No. 2
Population dynamics and efficacy of some insecticides against aphid on okra in gangetic plains of West Bengal
Author(s): A. KONAR, KIRAN A. MORE AND S K DUTTA RAY
Abstract: An experiment was conducted during two consecutive kharif season of 2010 and 2011 at Adisaptagram Block Seed Farm, Hooghly, West Bengal, India to study the population dynamics of aphid, Aphis gossypii (Glover) and efficacy of some insecticides against it on okra. The incidence of aphid was initiated during second week of July in both the years. Population of aphid was increased gradually to reach its peak during first week of September (39.28 aphids/3 leaves) when minimum and maximum temperature was 26.10°C and 33.50°C; minimum and maximum R.H. was 72.57% and 97.57%, respectively with 1.6 mm rainfall and persisted throughout the crop period with low incidence. Imidacloprid (a) 30 g a.i/ha was found most effective in reducing population of aphids and maximum net return was obtained from emamectin benzoate @ 18 g a.i.ha-1, the cost benefit ratio was recorded from imidacloprid treated plots i.e. 1:12.16.
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