Biology, morphometry and damage assessment of papaya mealybug, paracoccus marginatus williams and granara de willink (Hemiptera: pseudococcidae)

Abstract

Two experiments were conducted to study the biology and damage assessment of papaya mealybug in Sher-e- Bangla Agricultural University. In Biology study, each adult female laid one egg sack and per egg sack contained 123±19.52 eggs in average. The female had three instars’ nymphs and male had four. Average duration of female and male was 22.4±3.7 and 17.2±2.86 days, respectively. At 1^st instar male and female could not be distinguished, average length and breadth was 0.41±0.08 and 0.25±0.03 mm, respectively. Average length and breadth of 2^nd, 3^rd instar nymph and adult female were 0.69± 0.03, 0.44±0.02; 1±0.14, 0.72±0.05 and 1.94±0.27, 1.38 ±0.05 mm, respectively. The average length and breadth of 2^nd, 3^rd instar, pupa and adult male were 0.70±0.06, 0.38 ±0.04; 0.85±0.02, 0.41 ±.02; 0.94±0.04, 0.26 ±0.03 and 0.98 ±0.03, 0.26±0.01 mm, respectively. In damage assessment study, papaya plant was covered with fine net and imidacloprid (Admire) 200 SL @ 1ml/L of water was sprayed at 7 days interval and plants also artificially infested by papaya mealybug (100 papaya mealybugs per plant. Mealybug infestation reduced plant height (34.35%), number of leaves per plant (86.08%), petiole length (53.31%), number of flowers per plant (86.23%), number of fruits per plant (89.43%), individual fruit weight (88.01%) as well as total fruit yield per plant (98%). However, some plants showed a total loss in yield, indicating that 100% damage occurred for those plants.

Bangladesh J. Agril. Res. 49(2): 175-188, June 2024