Bionomics and population growth statistics of apterous virginoparae of woolly apple aphid, <i>Eriosoma lanigerum</i>, at constant temperatures

Abstract

Abstract Development, survival, reproduction and population growth statistics of apterous virginoparae of woolly apple aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae) at constant temperatures of 10, 13, 15, 20, 25, 30 and 32 °C are reported. The developmental times of all life stages were inversely related to temperature ranging from 10 to 30 °C. Span of total development (time from birth to adulthood) decreased from 57.8 days at 10 °C to 11.7 days at 30 °C and increased to 16.8 days at 32 °C. A good linear model fit (R 2 &gt; 0.96) between developmental rate and temperature in the range 10–25 °C was observed for all life stages. The lower developmental threshold was estimated at 5.8 °C for instar I, 4.8 °C for instar II, 4.9° for instar III and 4.4 °C for instar IV. The lower temperature threshold for total development was estimated at 5.2 °C. The upper developmental limit was found to be 32 °C. Mean degree‐day accumulations required for completion of instars I, II, III, IV and total development were: 125.6, 51.0, 47.7, 50.7 and 267.6, respectively. Fecundity, larviposition period and adult longevity were reduced with increasing temperature. Net reproductive rate was greatest at 15 °C whereas intrinsic rate of increase peaked at 25 °C. Optimal performance, as measured by fecundity, survival and intrinsic rate of increase, ocurred in the range 13–25 °C.