Temperatures lethal for citrus blackfly parasites,Encarsia opulenta andE. Smithi [Hym.: Aphelinidae]

Seasonally acclimatized adult and immature parasites of the citrus blackfly (CBF),Aleurocanthus woglumi Ashby, were exposed to high or low temperature extremes for 3 h periods. Death of all summer adults ofEncarsia opulenta Silvestri andE. smithi Silvestri occurred between 35° and 40°C. Within CBF hosts,E. opulenta were not able to emerge when temperatures reached between 45° and 50°C. In winter experiments adults of bothEncarsia species succumbed between −5° and −10°C. In a comparison of the 2 seasonal tests, a higher percentage ofE. smithi adults were able to survive both higher and lower temperatures thanE. opulenta, but the main interspecific difference was the ability ofE. opulenta within CBF to survive −10° to − 15°C whileE. smithi did not. Limited data forAmitus hesperidum Silvestri [Hym.: Platygasteridae] indicated that the immatures survived better at low, and not as well at high, temperatures as either species ofEncarsia. Florida Agricultural Experiment Station Journal Series # 5549.