LETHAL TEMPERATURES OF CITRUS BLACKFLY ALEUROCANTHUS-WOGLUMI [HOM, ALEYRODIDAE] AND ITS PARASITE, AMITUS-HESPERIDUM [HYM, PLATYGASTERIDAE]

Seasonally acclimatized citrus blackfly (CBF), Aleurocanthus woglumiAshby, and its parasite, Amitus hesperidumSilv. were exposed to extreme temperatures for 3-hour periods and survivorship measured. In summer experiments, the LD50 for CBF adults and 1st instar nymphs occurred between 40° and 45°C. The LD50 for A. hesperidum adults occurred between 35° and 40°C and increased with decreased humidity, although some adults could continue to emerge from parasitized CBF up to 45°C. In winter experiments, the LD50 for CBF eggs and adults occurred between -5° and -10°C and for other CBF stages between -10° and -15°C. The LD50 for adult A. hesperidum, and survival and emergence of the parasites from CBF both occurred between -10° and -15°C. Comparing data from the 2 seasons shows that adults are the most temperature sensitive stage of CBF and the parasite is more temperature sensitive than CBF, especially at higher temperatures. Correlating lethal temperature data with field meteorological conditions shows that short-term temperature exposures cannot be expected to stop the potential spread of CBF or A. hesperidum through Florida. © 1979 Le François.