Fruit rot of Loquat is a serious postharvest disease in Nagasaki Prefecture. The disease is primarily caused by the genera of Neopestalotiopsis (pathogen of gray leaf spot) and Pestalotiopsis. These pathogens are presumed to latently infect flowers and cause symptoms in fruit. The objective of this study is to elucidate the life cycle of these pathogens and to gain knowledge necessary for countermeasures.
In this study, we identified the pathogens of fruit rot and isolated fungi from healthy and diseased leaves, and asymptomatic flowers. Pathogenicity tests and molecular phylogenetic analysis were conducted using these isolates to detect sites of fungal infection in loquat trees. Furthermore, we sprayed nit mutants as a marker to flowers to prove that latent infection occurs in loquat. As a result, Neopestalotiopsis spp. were isolated from all collected specimens, while Pestalotiopsis spp. were isolated only from healthy leaves and flowers. The multiple species of both genera were pathogenic against loquat fruits.
These indicated that Neopestalotiopsis spp. and Pestalotiopsis spp. are pathogens of loquat which latently infect flowers and cause fruit rot as fruit ripens. The removal of gray leaf spot disease may lead to control fruit rot caused by Neopestalotiopsis spp. and further investigation is needed for Pestalotiopsis spp.