AbstractAutophagy serves as a survival mechanism and plays important role in nutrient recycling under conditions of starvation, nutrient storage, ad differentiation of plant pathogenic fungi. However, autophagy-related genes have not been investigated in Colletotrichum scovillei, a causal agent of pepper fruit anthracnose disease. ATG8is involved in autophagosome formation and is considered a marker of autophagy. Therefore, we generated an ATG8deletion mutant, ΔCsatg8, via homologous recombination to determine the functional roles of CsATG8in the development and virulence of C. scovillei. Compared with the wild-type, the deletion mutant ΔCsatg8exhibited a severe reduction in conidiation. Conidia produced by ΔCsatg8were defective in survival, conidial germination, and appressorium formation. Moreover, conidia of ΔCsatg8showed reduced lipid amount and PTS1 selectivity. A virulence assay showed that anthracnose development on pepper fruits was reduced in ΔCsatg8. Taken together, our results suggest that CsATG8plays various roles in conidium production and associated development, and virulence in C. scovillei.