Olive anthracnose

Olive anthracnose is the most important fungal disease of olive fruit worldwide causing heavy losses and olive quality reduction. It occurs in wet areas of many countries of the world. Several species or genotypes of Colletotrichum have been indicated as responsible for olive anthracnose in different olive-growing geographical areas, including C. acutatum sensu stricto, molecular groups A4 and A6 of C. acutatum, C. fioriniae, and C. simmondsii. Conidia are the infective propagules produced in acervuli on infected drupes; they are dispersed by rain splash and via wind-blown rain droplets. The sexual stages of Colletotrichum species causing olive anthracnose have not been observed on olive so far. Mummified drupes on the tree have been regarded as the inoculum reservoir. The incidence and severity of anthracnose vary considerably depending on the environmental conditions, the susceptibility of the olive cultivar and the virulence of the pathogen population. Susceptibility of the drupes to anthracnose increases with maturity, although green fruit of susceptible cultivars may be severely affected under favorable environmental conditions. Control of the disease is based on integrated management that includes chemical treatments, selection of resistant cultivars and early harvesting.