An investigation was conducted for biology, nature of infestation and control of Aphis gossypii against cultivated arum plants Colocasia esculenta. Morphological characteristics of the adults and nymphs were observed by a compound microscope. The adults were quite variable in color (viz. whitish, yellowish, pale or dark green). The 4 th instar nymph and adults were almost equal in size (0.22 ± 0. 005 mm long and 0. 05 ± 0. 002 mm broad). The most important feature of the adults was a pair

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... cles" or "siphunculi. These were gregarious on the host leaves, the numbers varied from on average from 250 to 280 on leaves and 210 to 250 on peduncles of leaves during the study periods. The highest 62% aphids were controlled using hand crushing technique in the month of February, 2012. The average value recorded from untreated experiments in October 2011 compared to data found in each month from mechanically treated plants by t-tests were significantly different (p < 0.05). Mean of the each month data were compared with each other using Tukey's Honest Significance Difference (HSD) test, where, no values were significantly different each other (p < 0.05) except data from first spread leaf in January, 2012.