Soil-mediated nutrient enhancement improves seed yield, nutrient physiology, and pest resistance in <i>Brassica napus</i> against <i>Brevicoryne brassicae</i>
Muhammad Wajid Javed, Mansoor ul Hasan, Muhammad Sagheer, Shahbaz Talib Sahi
Abstract
The cabbage aphid (Brevicoryne brassicae L.) is a cosmopolitan pest of brassica crops. The interactions among insect infestation, seed production, and seed physiology remain poorly understood. In this two-year field study, we evaluated silicon (Si) and ammonium sulfate (AS) as nutrient-based deterrents (applied at 25 and 50 kg ha− 1) compared to a conventional insecticide (Carbosulfan) for their effects on aphid resistance, seed yield, and seed nutrient physiology. Relative to the insecticide, Si at 25 kg ha− 1 reduced aphid populations by 16.2% and 13.5%, while Si at 50 kg ha− 1 reduced them by 24.3% and 21.9% in the first and second year, respectively. Similarly, AS at 25 kg suppressed aphids by up to 22.5% and 12.1% across the two years, whereas AS at 50 kg unexpectedly increased aphid numbers. Seed yield improved significantly with Si at 50 kg (28.7% and 30.9%), AS at 25 kg (14.6% and 15.9%), and AS at 50 kg ha− 1 (37.0% and 38.6%) in the first and second years, respectively. Nutrient analysis revealed that AS at 50 kg enhanced seed nitrogen, phosphorus, copper, and sulfur content, whereas Si at 50 kg increased potassium, magnesium, iron, calcium, zinc, and Si concentrations. These findings highlight the potential of Si and AS amendments in plant breeding programs to enhance pest resistance. Moreover, this study demonstrates the feasibility of optimizing fertilizer use for integrated pest management, reducing reliance on synthetic pesticides. Further research is needed to elucidate the underlying mechanisms by which these nutrients modulate plant defense against aphids.