Biology of Aphid, <i>Aphis gossypii</i> (Hemiptera: Aphididae) Glover Infesting Isabgol Crop

Abstract

Studies on the biology of aphid, Aphis gossypii (Glov.)on isabgol were carried out in laboratory condition at department of Agricultural Entomology, C. P. college of Agriculture, S. D. Agricultural University Sardarkrushinagar during 2008-2009. The results indicated that A. gossypii passed through four nymphal instars. The first instar nymph was oval in shape. The greenish brown to yellowish brown coloured first instar nymph subsequently changed to greenish brown to willow green, spinach and emerald green colour in second, third and fourth instars, respectively. The adult were bottle green to dark green in colour. The average duration of first, second, third and fourth instar nymphs was (2.04±0.16) days, (1.68±0.16) days, (2.00±0.17) days and (1.64±0.13) days, respectively with total nymphal duration of (8.64±0.20) days. The average length of first, second, third and fourth instar nymphs was (0.510±0.007) mm, (0.790±0.014) mm, (1.140±0.012) mm and (1.390±0.013) mm, respectively. The average longevity of adult was recorded as (16.36±0.54) days. Adults measured (1.68±0.020) mm in length and (0.890±0.110) mm in breadth. Average pre-reproduction, reproduction and post-reproduction period was (0.68±0.48) days, (15.50±0.56) days and (1.40±0.12) days, respectively. The total life span of A. gossypii was (23.76±0.65) days. The reproductive potential of the aphid was 46.50±0.65 nymphs per female for its entire life period and the average rate of birth was 6.50±0.52 nymphs per day per female.