Effect of propiconazole and difenoconazole on the control of anthracnose of chilli fruits caused by Colletotrichum capsici

Anthracnose of chillies caused by Colletotrichum capsici is a serious disease affecting the yield and quality of fruits. In vitro, greenhouse and field experiments were conducted to evaluate the efficacy of propiconazole, difenoconazole and carbendazim at different concentrations to control the pathogen and disease incidence. Among the fungicides, propiconazole exhibited the highest level of inhibition of in vitro mycelial growth, biomass production, sporulation and spore germination at concentrations as low as 0.1 μg ml−1. Enzyme (PG, PGTE, PTE and cellulases) production by C. capsici was significantly reduced by incorporation of fungicides into the growth medium. The highest degree of enzyme production inhibition was observed with propiconazole, followed by difenoconazole and carbendazim. Greenhouse and field experiments were conducted to study disease control by spraying propiconazole (0.1%, 0.05%, 0.025% a.i.), difenoconazole (0.05%, 0.025% a.i.) and carbendazim (0.1% a.i.). Application of propiconazole at 0.1% caused a dramatic reduction of disease incidence by 70% when compared to difenoconazole at 0.05% (58%) and carbendazim at 0.1% (44%). Additionally the fruit yield increased in the range of 86%, 63% and 60% for propiconazole, difenoconazole and carbendazim, respectively, when compared to unsprayed controls.