Fertilizer-Mediated Ditrophic Interactions between Aphis gossypii and Cucumber

The effects of different fertilizers including ‘Cow manure’, ‘Vermicompost’, ‘NPK’ (20-20-20 NPK), ‘NPKBN’ (NPK+Azotobacter vinelandii), ‘NPKBP’ (NPK+Pantoea agglomerans+Pseudomonas putida), and ‘NPKBNBP’ (NPK+Azotobacter vinelandii+Pantoea agglomerans+Pseudomonas putida) were compared with the control treatment. Comparisons included not only the nutrient and chlorophyll content of cucumber leaves, but also the demographic parameters and body size of Aphis gossypii Glover. The highest nitrogen content (2.45%) was observed in ‘NPKBN’ and the highest phosphorus, along with potassium content (0.58 and 12.17%, respectively) was observed in ‘cow manure’ treatment. The highest chlorophyll content (37.51 SPAD units) was measured in ‘NPKBNBP’ treatment. Results showed that the intrinsic rate of increase (r) varied from 0.409 (in ‘Cow manure’) to 0.480 d^-1 (in ‘NPKBP’) under application of different fertilizers. Net Reproductive rate (R0) varied from 71.65 to 79.25 nymphs/individual in ‘Vermicompost’ and ‘NPKBP’ treatments, respectively. The largest (1.28 mm) and smallest (1.00 mm) body length of the aphids was measured on ‘Vermicompost’ and ‘Control’, respectively. Results revealed that ‘NPKBP’ was the most suitable fertilizer for population growth of A. gossypii, compared with the other treatments, and the aphid’s longevity and fecundity was relatively low under ‘Vermicompost’ application.