Biology of aphid, Aphis gossypii Glover in cumin

Abstract

The experiment on biology of aphid, Aphis gossypii infesting cumin crop was conducted under ambient conditions in the Entomology Laboratory, Agricultural Research Station, Mandor, Jodhpur. The study was conducted on potted plants of cumin variety GC-4. The aphid, A. gossypii nymphs were moulted four times before attaining the adult stage. The mean body length, width, antennal length and cornicle length of first, second, third and fourth instar nymphs were 0.50 ± 0.04, 0.28 ± 0.03, 0.28 ± 0.02 and 0.036 ± 0.01 mm; 0.90 ± 0.04, 0.38 ± 0.04, 0.40 ± 0.03 and 0.065 ± 0.01 mm; 1.11 ± 0.05, 0.49 ± 0.04, 0.54 ± 0.03 and 0.095 ± 0.01 mm and 1.31 ± 0.06, 0.65 ± 0.05, 0.64 ± 0.04 and 0.175 ± 0.01 mm, respectively. The mean body length, width, antennal length and cornicle length of adult aphid were 1.68 ± 0.06, 0.71 ± 1.53, 0.88 ± 0.02 and 0.266 ± 0.01 mm, respectively. The mean duration period of first, second, third and fourth instar nymphs were 1.30 ± 0.42, 2.05 ± 0.62, 2.40 ± 0.52 and 1.45 ± 0.45 days, respectively. The total nymphal duration was 7.75 ± 1.61 days. The mean longevity of adult aphid was 9.65 ± 1.75 days with an entire life span of 17.75 ± 2.91 days. The pre-reproductive, reproductive and post-reproductive periods were 1.35 ± 0.56, 7.20 ± 1.47 and 1.75 ± 0.71 days, respectively. The fecundity of the adult female was 24.45 ± 6.21 nymphs per female and the intrinsic rate of single female per day was an average of 4.80 ± 2.01 nymphs/day.