Tabelas de esperança de vida e fertilidade de Myzus persicae sobre pimentão em laboratório e casa de vegetação

Abstract

Life table studies of insect pests in different temperatures aid in comprehension on the population dynamics of these organisms. In this study, fertility and life expectancy tables were built for the green peach aphid Myzus persicae reared on pepper Capsicum annuum under different thermal conditions. In laboratory, the study was carried out at 15, 20, 25, and 30 °C, 70±10% RH and 12 h photophase, and in greenhouse at oscillating temperature with average of 24.9 °C and 68.1% RH. The longest M. persicae longevity was at 15 °C (45 days), decreasing at 20 °C (39 days), 25 °C (27 days) and 30 °C (24 days). Under greenhouse condition at 24.9 °C, the longevity was 29.5 days. The life expectations (e x) in the first day of observation were 43.76; 35.39; 21.44; 17.67 and 17.03 days for the nymphs maintained at 15, 20, 25, 30, and 24.9 °C, respectively. From this point on, the e x decreased until the end of the observations. The fertility life table parameters, on a day time scale, indicated that the temperature of 25 °C provided the best thermal conditions for the growth of M. persicae, with the highest intrinsic rate of natural increase (r m = 0.31) and the shortest time needed for the population to double in size (TD = 2.22 days). The temperature variation in greenhouse affected the aphid population growth, with a low r m value (0.28) and a long TD (2.47), compared to those maintained at 25 °C.