Efficacy of plant resistance inducers in controlling anthracnose disease in chili pepper

Abstract

Chili production faces significant yield losses due to anthracnose disease caused by Colletotrichum spp. Conventional chemical control methods are limited by concerns over chemical residues and the development of pathogen resistance. This study aimed to identify the causal agents of anthracnose disease and to evaluate the effectiveness of resistance-inducing agents for sustainable disease management. Chili samples showing disease symptoms were collected from Nakhon Pathom and Kanchanaburi provinces. The pathogens were isolated and identified based on morphological characteristics, revealing C. truncatum and C. gloeosporioides. Pathogenicity tests on seven chili cultivars at the fruiting stage showed that the cultivar CA365×1355 was highly susceptible to C. truncatum. The efficacy of four plant resistance inducers salicylic acid, acibenzolar-S-methyl, β-aminobutyric acid and chitosan was evaluated on the susceptible cultivar CA365×1355. Disease severity was assessed after treatment and inoculation. At 14 days after treatment, salicylic acid, β-aminobutyric acid, and chitosan reduced disease incidence by 75.35%, 65.19%, and 39.25%, respectively, with consistent results observed at 21 days. The findings indicate that resistance-inducing agents, particularly salicylic acid and β-aminobutyric acid, are effective in controlling anthracnose caused by C. truncatum. These agents represent environmentally friendly alternatives for sustainable chili disease management. This study provides a foundation for the development of integrated plant disease management strategies in the future.