ABSTRACT Anthracnose caused by Colletotrichum horii is one of the most important diseases in the persimmon tree. This study aimed to determine the influence of environmental variables on conidia germination, mycelial growth, and infection in persimmon fruit and shoots/twigs. The germination was quantified at 10, 15, 20, 25, and 30°C, with 6, 12, and 24 hours of wetness period. The effects of the same temperatures were also evaluated for mycelial growth, sporulation, and infection on ‘Fuyu’ fruit. The infection on shoots/twigs were quantified at 5, 10, 15, 22, 25, 27, and 35°C. The conidia germinated at all temperatures and wetness combinations, except at 10°C, with 6 hours of wetness. At 24 hours of wetness, the optimal temperature for conidia germination was 21.3°C. The optimal temperature for mycelial growth ranged between 21.7 to 24.3°C. The optimal temperature for lesion growth on fruit was 25.7°C; at 25°C, the incubation period was of two days, and the latent period lasted 12 days. On shoots/twigs, the temperature of 35°C anticipated in two days the onset of symptoms and 5-10°C delayed in eight-10 days the onset of symptoms in relation to temperature of 25°C. In nonlignified shoots, C. horii can cause symptoms from 15 to 35°C. In lignified twigs, C. horii was able to cause symptoms from 5 to 35°C. Because of the incidence and disease progression in most of climatic situations, our results reinforce the importance of monitoring and constantly removing diseased shoots, twigs, and fruits from the orchard to reduce the spread of the pathogen.

ABSTRACT The Glomerella leaf spot (GLS) and bitter rot (BR) are important apple diseases in Brazil, caused by species of Colletotrichum, which are usually related with quiescent infection. This study aimed to detect quiescent infections of Colletotrichum spp. in flowers and in unripe fruits from apple commercial orchard cultivars Eva and Gala. The pathogen was observed in various structures of the flower in both cultivars. In unripe fruits, the pathogen was recovered only from ‘Eva’. Five isolates were obtained and were inoculated by mycelial (with and without wound) on ripe apple fruits and by conidia suspension (without wound) on ripe apple fruits and leaves of ‘Gala’. On inoculated fruits by mycelial, the isolates induced symptoms of BR, and on inoculated fruits by conidia without wound the isolates induced symptoms of GLS. On inoculated leaves, isolates induced symptoms of GLS. The isolates were characterized by cultural, morphological and pathogenic aspects. Detection of Colletotrichum spp. in asymptomatic apple flowers is epidemiologically important, since the flowers can be a route for infection in unripe fruits. This is the first investigation of quiescent infection of this pathogen on apple flowers.

RESUMO: Várias doenças podem estar associadas com figos, mas recentemente uma podridão dos frutos foi observada em frutos verdes. O objetivo deste estudo foi determinar a patogenicidade de Botrytis sp., quantificar o período de incubação (PI) e o período de latência (PL), verificar a temperatura ótima para o crescimento micelial e identificar as diferentes espécies de Botrytis sp. isoladas a partir de frutos imaturos de figo. Botrytis sp. isolado a partir de figos provou ser patogênico em frutos imaturos com e sem ferimento na superfície dos frutos e no ostíolo. O PI foi de 3 dias em frutos com ferimento e 5 dias em frutos inoculados no ostíolo e sem ferimento. O PL foi de 6 dias em todos os tratamentos. A temperatura ótima de crescimento micelial foi18°C. A partir de sequências de um segmento que compreende a região de ITS do DNA ribossomal, concluiu-se que os isolados são Botrytis cinerea.

ABSTRACT: Several diseases can be associated with figs but recently a fruit rot was observed in green fruit. The purpose of this study was to determine the pathogenicity of Botrytis sp., to quantify incubation period (IP) and latent period (LP), to verify the optimum temperature for mycelial growth, and to identify the different species of Botrytis sp. isolated from immature figs. Botrytis sp. isolated from figs proved to be pathogenic to immature fruit with and without wounding the fruit surface and ostiole. The IP period was 3 days on fruit with wounds and 5 days on fruit inoculated within the ostiole (without wound). The LP was 6 days in all treatments. The optimum temperature for mycelial growth was 18°C. Inferred from sequences of a segment comprising the ITS region of ribosomal DNA concluded that the isolates are Botrytis cinerea.