Evaluation of Chili Germplasm against Leaf Spot and its Management by Nutrients and Fungicides

Abstract

Chili (Capsicum annum L.) is a widely grown vegetable in tropical and subtropical areas that is attacked by a diverse range of bacterial and fungal pathogens, causing severe yield and quality losses. Alternaria leaf spot, caused by Alternaria alternata, is the major fungal disease of chili that deteriorates the vitality of the crop. The objective of the current research is to identify the most effective nutrient combination and fungicide against Alternaria leaf spot disease and to evaluate resistant sources. The current research was conducted using six varieties (CH-121, Chilli-900 F1, Red Wing, SAYBAN, AAHP-1, and Diamond CH-121) collected from Ayub Agricultural Research Institute, Faisalabad, Pakistan. Seeds were sown in the Plant Pathology field area, University of Agriculture, Faisalabad, to screen against leaf spot disease. The effect of different fungicides and nutrients to overcome chili leaf spot was studied, and three treatment combinations were prepared: (ZnSO4 (ZS) + MnSO4 (MS) + boric acid (BA) + Topsin M), (ZS + MS + BA + Mancozeb), and (ZS + MS + BA + Vitavax). Among these, the combination of (ZS + MS + BA + Vitavax) was the most effective against leaf spot disease. Minimum disease severity was observed with ZS + MS + BA + Vitavax in CH-121 (15.00), while maximum disease severity was observed with the control in Red Wing (93.67). Environmental data were collected and statistically analyzed. There was a significant (p 0.05) but positive correlation between maximum temperature, minimum temperature, wind speed, rainfall, and disease severity. There was a negative correlation between relative humidity and disease severity. In conclusion, micronutrients were found to enhance Alternaria leaf spot tolerance in chili plants, providing a cost-effective and easily obtainable solution. The combined use of nutrients and fungicide is effective in preventing the development of resistance in pathogens against fungicides.