Development, survival and reproduction of Euseius finlandicus (Acari: Phytoseiidae) at different constant temperatures.

Development, survival and reproduction of Euseius finlandicus Oudemans were studied at seven constant temperatures (15, 20, 25, 27, 30, 32 and 34 degrees C) in the laboratory. Within the temperature range tested, developmental period from egg to adult varied from 148 to 360.5 h and 133.7 to 336.5 h for females and males, respectively. The lower thermal threshold for immature development for females and males was 8.9 and 6.4 degrees C, respectively. Survival during immature development exceeded 90% at all the temperatures from 15 to 32 degrees C, but at 34 degrees C an abrupt decline was recorded. Female longevity decreased gradually from 82.7 d at 15 degrees C to 12.2 d at 34 degrees C. The mean generation time ranged from 44.3 d at 15 degrees C to 15.9 d at 32 degrees C. The highest rm value (0.2817) was obtained at 30 degrees C and the lowest at 15 degrees C (0.0976). Temperatures above 30 degrees C had an adverse effect on population increase.