Abstract

An invasive mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) has attacked cotton (Gossypium hirsutum L.) seriously in Pakistan and India, and caused great loss in the production of cotton in recent years. This kind of pests can probably spread rapidly and would threaten cotton and other crops in many infested and non-infested countries. P. solenopsis has first been reported to severely damage Chinese hibiscus (Hibiscus rosa-sinensis) in Guangzhou, in December, 2008. In order to understand the effects of temperature on the development of P.solenopsis, the developmental threshold temperature (C_t) and effective accumulated temperature (K) were calculated for each developmental stage. A total of 30 P. solenopsis individuals were divided into 6 groups and reared at six constant temperatures (18, 21, 24, 27, 30, and 33°C). Total developmental duration ranged from 81.3 days at 18°C to 24.06 days at 30°C for female mealybug, and from 44.21 days at 18°C to 12.95 days at 30°C for male mealybug. Degree-day values for each developmental stage for both male and female mealybugs were determined. Total degree-day values required for full  development for female and males were 414.9 and 218 degree-days respectively. Estimated threshold temperatures for different life stages ranged from 12.8°C (pre-oviposition) to11.7°C (3^rd instar) for female mealybugs, and 16.5°C (prepupa) to 11.5°C (2^nd instar) for male mealybugs.

Key words: Mealybug, Phenacoccus solenopsis, development, temperature.