Impact of nitrogenous fertilizer rates on Schizaphis graminum (Rondani) population dynamics in wheat (Triticum aestivum L.)

Abstract

Sustainable wheat crop production for improved growth and yield depends on the balanced use of nitrogenous fertilizers. However, their inadequate usage often provides a favorable environment for the sucking insect pests like aphids to flourish. Field research was performed to assess the effect of elevated levels of nitrogenous fertilizer on Schizaphis graminum population in a randomized complete block design (RCBD) with four replications at the research farm area of the Faculty of Agricultural Sciences and Technology (FAS&T), Bahauddin Zakariya University, Multan. Five different doses of nitrogenous fertilizers, i.e., 0, 50, 75, 100, and 125 kg/acre, were used. The results revealed a significant correlation between the average number of S. graminum per plant and nitrogen fertilizer application in both years. Infestation by S. graminum nymphs reached its highest levels during the 2^nd week of February and the 1^st week of March during 2024 while in 2025 peak was observed in 2^nd and 3^rd week of February. The first peak recorded 17.8 nymphs/plant, while the second peak reached 16.9 nymphs/plant on February 12^th during 2024. Similarly in 2025 first peak recorded 18.3 nymphs/plant, while the second peak reached 16.2 nymphs/plant on February 26^th and 12^th. The 2^nd and 3^rd week of February presence of S. graminum on wheat crops was observed from January 15^th through April 9^th, with the overall population peaking on February 26^th at 18.3 nymphs/plant. The study further examined the influence of varying nitrogen application rates, specifically 0, 50, 75, 100, and 125 kg/acre, on the population density of S. graminum. Nitrogen levels had a statistically significant impact on both nymph and adult populations in both years. The lowest population densities were recorded at application rates of 0, 50 and 75 kg/acre. © 2026 The Author(s)