Temperature-dependent development of Anagyrus pseudococci (Hymenoptera: Encyrtidae) as a parasitoid of the vine mealybug, Planococcus ficus (Homoptera: Pseudococcidae)

The influence of temperature on Anagyrus pseudococci (Girault) development and overwintering was investigated to improve biological control of the vine mealybug, Planococcus ficus (Signoret), in California vineyards. At a constant 32 °C, egg development required 2 days, larval development ranged from 0.7 ± 0.1 (second instar) to 1.9 ± 0.1 (fifth instar) days, and pupal development was 3.9 ± 0.1 days. Under eight constant temperatures (12, 14, 17, 22, 27, 32, 34, and 36 °C), A. pseudococci completed development (egg to adult eclosion) from 14 to 34 °C. Development times ranged from 79.1 ± 1.0 days (14 °C) to 10.2 ± 0.3 days (34 °C). We determined optimal, maximum and minimum development temperatures to be 24.7, 36.0 and 11.6 °C, respectively, and the thermal constant is 223.5 degree-days. We compared these laboratory-derived temperature relationships to A. pseudococci field-monitored populations from March through November. Laboratory-data suggests there are seven to eight A. pseudococci generations during this period, two generations to each vine mealybug generation. Overwintering studies show that A. pseudococci emergence was concentrated over a 15 day period in early May, regardless of when vine mealybugs were exposed (October 2001 to March 2002). Results suggest that cues other than temperature are used to synchronize overwintered A. pseudococci adult emergence with field availability of vine mealybug.