Biology of two spotted spider mite, Tetranychus urticae (Acari: tetranychidae) on taro

Abstract

The biology of twospotted spider mite, Tetranychus urticae Koch was studied at the Integrated Pest Management Lab of Entomology division, Bangladesh Agricultural Research Institute (BARI) Gazipur following leaf disc method during March-May, 2022 at 25±2⁰ C and 55±5% RH. It was revealed that biology of T. urticae consisted of egg, larva, protonymph, deutonymph and adult stages and brief quiescent period called nymphochrysalis, deutochrysalis and teliochrysalis. Egg incubation period 2.90±0.29, larval 1.3±0.2 and 2.7±0.54, protonymphal 2.8±0.25 and 3.0±0.35 and deutonymphal period of 2.4±0.43 and 2.9±0.51 days were recorded in its male and female, respectively. Males took less time to develop overall 6.45±0.30 days than females 8.25±0.28 days from egg to adult emergence. Males were smaller than females, according to morphometric measurements. Both parthenogenetic and bisexual reproduction were noted. The offspring of mated females were 1:2.32 males to females, while unmated females produced only males. An average of 62.0 ± 8.98 eggs were produced by mated females and 38.2 ± 6.36 by unmated females. Correspondingly mated females laid 7.0 to 10.0 (mean 8.6±0.68) and unmated females laid 2.0 to 5.0 (mean 4.0±0.55) eggs per day. The observed adult longevity was 9.30± 0.83 days for males, 12.2±0.80 days for mated females, and 10.0±1.3 days for unmated females, respectively.

Bangladesh J. Agril. Res. 49(3): 305-314, September 2024