Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Selection of Clonostachys rosea isolates from Brazilian ecosystems effective in controlling Botrytis cinerea(Biological Control, 2005-08) Nobre, Sérgio A. M.; Maffia, Luiz Antônio; Mizubuti, Eduardo S. G.; Cota, Luciano Viana; Dias, Ana Paula S.Clonostachys spp. were isolated from soil samples, and living and dead leaves of different plant species. Twelve isolates which sporulated well when cultured on agar media were compared regarding the capacity of establishing and suppressing Botrytis cinerea in leaves of Rosa hybrida ‘Sandra,’ Fragaria × ananassa ‘Dover,’ Lycopersicon esculentum ‘Kada,’ and Eucalyptus globulus. The isolates established in leaves of each plant species, but leaf area with conidiophores (SFCA) varied with the stage of leaf development. In rose, SFCA varied from 3.0 to 13.9% on senescing leaves and 3.4 to 10.0% on green leaves. SFCA was higher in young leaves of E. globulus and tomato (1.4–15.6% and 1.4–8.0%, respectively) than on senescing leaves (0.8–3.5% and 1.0–5.2%, respectively). In strawberry, SFCA varied from 0.7 to 6.2% on completely expanded leaves. Clonostachys rosea isolates reduced B. cinerea sporulation on leaves of rose (81.0–97.4% reduction), strawberry (87.6–96.8%), E. globulus (63.7–89.7%), and tomato (100% reduction). Four isolates of C. rosea were selected based on high levels of SFCA and suppression of B. cinerea. When leaf discs of the four hosts inoculated with these C. rosea isolates were challenged with isolates of B. cinerea of variable levels of aggressiveness, SFCA and pathogen suppression varied with the combination. Efficiency of C. rosea isolates in suppressing sporulation of B. cinerea varied among hosts but was always above 80%. The four selected Brazilian isolates of C. rosea are potential biocontrol agents for Botrytis blight management in Brazilian agricultural systems.Item Biological control of strawberry gray mold by Clonostachys rosea under field conditions(Biological Control, 2008-05-03) Cota, Luciano V.; Maffia, Luiz A.; Mizubuti, Eduardo S. G.; Macedo, Paulo E. F.; Antunes, Ricardo F.Gray mold, caused by Botrytis cinerea, is an important strawberry disease in Brazil. As a component of a disease management program, we have been evaluating pathogen biological control with Clonostachys rosea, and selected four isolates as potential antagonists to B. cinerea. In 2006 and 2007, under field conditions, we compared the efficiency of the four C. rosea isolates (applied once or twice a week) with a weekly spray of procymidone alternated with captan in controlling gray mold. Following the applications and up to harvest, we evaluated weekly: leaf area colonization by C. rosea (LAC), average number of B. cinerea conidiophores on leaves (ANC), incidence of gray mold on both flowers (Iflower) and fruits (Ifruit), incidence of latent infections on fruits (Ilat), and yield. The applications of C. rosea twice a week provided higher LAC (16.97%), smaller ANC (10.28; 78.22 in the check treatment, sprayed with water), smaller IFlower (10.02%; 50.55% in the check treatment), and smaller IFruit (5.95%; 25.10% in the check treatment). Yield ranged between 3490 and 3750 g plot^−1 with applications of C. rosea twice a week and between 1740 and 1910 g plot^−1 in the check treatment. Ilat was 20% in the check treatment and less than 10% in the other treatments. Based on this 2-year study, at least two weekly applications of C. rosea are required for a successful gray mold management program.