Evaluating the Efficiency of Irrigation Methods and Their Interaction with Some Factors in a Control Program for Onion Leaf Blight Caused by the Fungus Stemphylium vesicarium

This study was conducted to evaluate the efficiency of two irrigation methods (drip and sprinkler) and their interaction with some chemical and agricultural treatments within an integrated program to control onion leaf blight caused by the fungus Stemphylium vesicarium. This was achieved through a field experiment that included nine treatments: potassium silicate, the fungicide trifloxystrobin, the insecticide acetamipride, basal leaf removal, binary interactions between these substances, and two control treatments (contaminated and uncontaminated). Each treatment was implemented under both drip and sprinkler irrigation methods. The results showed a significant advantage of drip irrigation over sprinkler irrigation in all studied traits. Drip irrigation recorded the lowest infection rate (60.00%) and lowest infection severity (0.17) compared to sprinkler irrigation (70.00%) and (0.20%), respectively. It also outperformed sprinkler irrigation in leaf area, biological weight, and yield. The interaction between irrigation method and treatments showed that the potassium silicate + trifloxystrobin fungicide treatment under drip irrigation achieved the best overall performance, recording the lowest infection rate (36.66%) and the highest yield (178.33 g/plant⁻¹), while the contaminated control treatment under sprinkler irrigation recorded the lowest results. These results indicate that using drip irrigation reduces the leaf wetness period and the associated conditions conducive to fungal spore germination, and that incorporating this irrigation method into integrated disease management programs contributes to reducing infection and improving productivity.