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.

Desenvolveu-se este trabalho com o objectivo de avaliar o efeito de extratos de canela (12%), alho (8%), pimenta (16%), tabaco (6%), e das caldas viçosa, bordalesa, sulfocálcica e sulfocálcica em emulsão (todas a 1%) em cinco isolados de Stemphylium solani e a eficácia dos mesmos em controlar a doença no tomateiro em estufa. Nos testes in vitro, utilizaram-se clorotalonil (1800 mg.L-1) e água como testemunhas e avaliaram-se o efeito dos tratamentos no crescimento micelial, germinação e produção de conídios. Em estufa, avaliou-se o efeito dos tratamentos na área abaixo da curva da progressão da doença (AACPD) e na produção de frutos, alterando o fungicida utilizado como testemunha para mancozebe (3 g.L-1). Observou-se grande variabilidade entre os isolados quanto à sensibilidade aos tratamentos. Estes não afetaram a esporulação, excepto a calda sulfocálcica em emulsão que a estimulou em todos os isolados. As caldas bordalesa e viçosa inibiram completamente o crescimento micelial e reduziram significativamente a germinação dos conídios na maioria dos isolados. Os extratos vegetais e as caldas causaram redução da AACPD comparado à testemunha água, especialmente a calda bordalesa, mas não afetaram a produção de frutos.

The aim of this work was to evaluate the effect of extracts of cinnamon (12%), garlic (8%), pepper (16%) and tobacco (6%) and viçosa mixture, bordeaux mixture, lime sulfur and sulfur emulsion (all 1%) on five isolates of Stemphylium solani and their efficiency in disease control of tomato in greenhouse. In tests in vitro, chlorothalonil (1800 mg.L-1) and water were used as controls and the mycelial growth, germination and the production of conidia were evaluated. At greenhouse, the treatments effect on the area under the disease progress curve (AUDPC) and production of fruits was evaluated, altering the fungicide control to mancozebe (3 g.L-1). There was high variability among isolates concerning sensitivity to treatments. Treatments did not affect spore production, except lime sulfur emulsion, which stimulated it in all isolates. Viçosa and bordeaux mixtures inhibited completely the mycelial growth and reduced significantly the conidial germination in most isolates. The extracts and mixtures decreased the AUDPC compared to water control, mainly bordeaux mixture. The treatments did not affect the fruits production.