Influence of nitrogen fertilization on biology of Aphis gossypii (Hemiptera: Aphididae) reared on Chrysanthemum indicum (Asteraceae)

The experiment studied the effect of different nitrogen levels on the biology and life table parameters of the cotton aphid, Aphis gossypii Glover reared on Chrysanthemum indicum Kitan. The fertilizer treatments were administered at 0, 25, 50, 100 and 150% of the agronomic recommended concentration. The aphids were collected from greenhouses in Mahalat and transported to pots. The different nitrogen fertilizer levels did not show a specific effect on the potassium and phosphorus content in leaves. The intrinsic rate of increase and net reproductive rate ranged from 0.173 to 0.225, and 15.47 to 28.28, respectively, at different tested fertilizer levels. The aphids showed the significantly lowest mean generation time and the highest finite rate of increase when fed on chrysanthemum fertilized at a 150% fertilizer level. The aphids fecundity and survival showed a positive correlation when the fertilizer concentration was increased. On the other hand, the highest life expectancy was obtained for the aphids fed on chrysanthemum with a 25% nitrogen level. The present data suggest that plant nitrogen content is an important factor contributing to the increase severity of the cotton aphid as a pest of chrysanthemum.