Author(s): D. DAHAL, P. S. MEDDA* AND J. GHOSH

Abstract: Black fly (Aleurocanthus rugosa Singh) is an important pest in betel vine particularly under Tarai region of West Bengal. Experiments were conducted to find out the population build up of black fly in betel vine as influenced by climatic factors and efficacy of some insecticides under the boroj of the instructional farm, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal during the period from Nov.,2005 to Apr.,2007. Population of black fly was found active throughout the year but the maximum (20 nos./ leaf) and minimum (1.2 nos./ leaf) population (nymphs & adults) was recorded at 44th standard week of 2006 and at 16th standard week of 2007 respectively. Simple correlation analysis revealed no significant correlation between abiotic factors with black fly population; though population was positively correlated with maximum and minimum temperature, maximum relative humidity but negatively with minimum relative humidity and rainfall in the present study. Multiple regression analysis showed significant variation and the R2 value suggested that the biotic factors contribute 20% variation in blackfly population. Among ten (10) different insecticides, the highest mortality (74.53%) of black fly was found in the Imidachlorprid treated plots though it was at par with acetamiprid and quinolphos + cypermethrin combined product..

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