Bottom-up Effect of Two Host Plants on Life Table Parameters of Aphis gossypii (Hemiptera: Aphididae)

Aphis gossypii Glover is one of the most important pests of greenhouse cucumber and pepper in the world and Iran. In this research, life table and biology of A. gossypii were investigated on cucumber (Cucumis sativus cv. Super Sultan) and pepper (Capsicum annum cv. Marqueza) in a growth chamber at 25±1°C and 60±5% RH and a photoperiod of 14 L: 10 D hour.The results showed thatdevelopmental time of A. gossypii on pepper was significantly longer than that on cucumber. The survival rates of A. gossypii on cucumber and pepper were significantly differentbased on Kolmogrov-Smirnov test results. The survival rates (lx) at the beginning of female emergence were 94 and 66% on cucumber and pepper, respectively. Life expectancy (ex) of the newly-bornnymphs of A. gossypii were obtained as 26.37 and 14.4 days on cucumber and pepper, respectively. The highest age-specific daily fecundity of A. gossypii was at the 5th and 6th days of female adult age on cucumber and from first to 4th days of female adult life on pepper. Furthermore, two mathematical models (Analytis and Enkegaard) were fitted to age-specific fecundity data (mx). Adult longevity of A. gossypii on cucumber was significantly higher than that on pepper. The R0, rm and λ-values of A. gossypii on cucumber were significantly higher than those on pepper. The cotton aphid exhibited longer mean generation time (T) on pepper than that on cucumber. According to the growth index and life table statistics, cucumber was the suitable host plant for A. gossypii.