Unveiling the Antibacterial Potential of Plant Defence Activators in Conjunction with Meteorological Variables against Bacterial Leaf Spot in Spinach

Spinach is susceptible to various fungal, bacterial, and viral pathogens. Among these, bacterial leaf spot poses a significant threat, leading to substantial reductions in both yield and quality. Recent research focused on evaluating different plant defense activators for their effectiveness against bacterial leaf spot in spinach. Of the tested activators, Salicylic acid showed the lowest disease severity and incidence, with values of 24.76% and 27.73%, respectively, followed by Citric acid (27.43%, 32.76%), Benzoic acid (29.57%, 38.32%), and K2HPO4 (33.31%, 38.38%) under greenhouse and field conditions, compared to the control. Various epidemiological factors—including temperature (minimum and maximum), relative humidity (%), rainfall (mm), and wind speed (km/h)—were assessed for their impact on disease development in three local spinach varieties: Dasi Palak, Lahori Palak, and Swiss Chard Palak. The results showed that disease severity increased considerably when the temperature ranged from 26-28°C, relative humidity was 69-73%, rainfall was 0.5-1 mm, and wind speed was 1.5-2 km/h. All environmental factors exhibited a positive correlation with the development of bacterial leaf spot in spinach. Greenhouse and field trials were conducted using a Complete Randomized Design (CRD) and a Randomized Complete Block Design (RCBD), respectively. Based on the findings, the application of Salicylic acid is recommended as a reliable and ecologically sound strategy for managing bacterial leaf spot in spinach.