Influence of Nitrogen Fertilizer on Cotton Host-Plant Quality and Its Impact on Cotton Aphids

An ongoing multi-year comprehensive field study has examined the effect of soil nitrogen (residual nitrogen plus applied nitrogen) on cotton agronomic growth parameters and arthropod abundances under a drip irrigation production system for 11 years. Fixed-rate nitrogen application experimental plots, previously established and fixed consisted of five augmented nitrogen fertility levels (0, 50, 100, 150, and 200 lb/acre) with five replications. Although four synthetic pyrethroid applications were applied to all treatment plots during August-September 2013 to encourage a cotton aphid buildup, observed aphid numbers remained non-existence for 2013. Nitrogen augmentation rates significantly influenced all agronomic parameters evaluated in this study, most with curvilinear relationships. These relationships observed in 2013 are similar to what have been observed in previous years.