EFFECT OF TEMPERATURE ON DEVELOPMENT RATE AND INTRINSIC RATE OF INCREASE OF APHIS-GOSSYPII REARED ON GREENHOUSE CUCUMBERS

Thermal requirements for development and life table statistics of Aphi s gossypii Glover (Homoptera, Aphididae) were determined over a range of constant temperatures from 10 to 30 degrees C. The lower developmen t threshold and the sum of effective temperatures were 6.9 degrees C a nd 90.1 degrees C, respectively, for preimaginal development, and 5.8 degrees C and 113.6 degrees C from birth to the onset of reproduction. Mean total fecundity ranged from 36 larvae per female at 10 degrees C to 76 larvae at 30 degrees C. On a time scale of days, net reproducti ve rate (R(o)) increased with increasing temperature while generation time (T) decreased causing the intrinsic rate of increase (Upsilon(m)) to increase linearly from 0.115 to 0.465. On a day-degree scale Upsil on(m) only varied from 0.019 to 0.028 because the growth of R(o) was c ompensated by an increase in T with increase in temperature. The nearl y constant Upsilon(m) in terms of day-degrees, over a wide range of te mperatures, greatly simplifies the prediction of future population num bers of A. gossypii.