The cotton aphid, Aphis gossypii is a known pest in the agricultural industry. Aphid growths are influenced by environmental conditions, such as the species of the plant and soil nutrition. The cucumber, Cucumis sativus L var. Beit Alpha is the main host of A. gossypii. The aim of this research was to study the effect of nitrogen fertilizer on A. gossypii, including biological performance, number of alate and apterous individuals, and its life span. Three different doses of nitrogen fertilizer were used, 0, 0.5, and 0.75 g under laboratory conditions. Each treatment was replicated in triplicates. The life span of A. gossypii in the cucumber was found to be 27.5 +/- 9.52 days, which consisted of 5.1 +/- 0.57 days of the nymphal period and 21 +/- 1-day in the adult period. The average of number progeny was determined to 74.7 +/- 14.58. At the end of the growth period, the populations of A. gossypii in each nitrogen treatment were 614.33 +/- 579.26 (0.75 g), 602.25 +/- 159.63 (0.5 g), and 854.75 +/- 453.82 (0 g). These populations indicate that there was no significant difference between the treatment. However, the infestation of A. gossypii caused the plant to wilt and suppressed its growth, and this infestation rate increased as the nitrogen level increased. Overall, it was found that nitrogen affected the progeny number, population, and life span of A. gossypii.
