Clonostachys rosea no controle biológico e manejo integrado do mofo cinzento do morangueiro

• Ano de defesa: 2008
• Autor(a) principal: Cota, Luciano Viana
• Orientador(a): Maffia, Luiz Antônio
• Banca de defesa: Teixeira, Hudson , Morandi, Marcelo Augusto Boechat
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitopatologia
• Departamento: Etiologia; Epidemiologia; Controle
• País: BR
• Palavras-chave em Português: Controle biológico; Morango; Clonostachys rosea
• Palavras-chave em Inglês: Biological control; Strawberry; Clonostachys rosea
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1013

Gray mold, caused by Botrytis cinerea (Bc), is an important strawberry disease in Brazil. As a component of a disease management program, we have been evaluating pathogen biocontrol with Clonostachys rosea (Cr). In 2006 and 2007, we set field experiments to evaluate the potential of Cr on biological control and on integrated management of gray mold. We compared the efficiency of four Cr isolates (applied once or twice a week) with a weekly spray of procymidone alternated with captan in controlling gray mold. Following the applications and until the harvest, we evaluated weekly: leaf area colonized by Cr (LAC), average number of Bc 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 Cr 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, with applications of Cr twice a week and between 1740 and 1910 g/plot in the check treatment. Ilat was 20% in the check treatment and less than 10% in the other treatments. Biological control by Cr was most efficient than fungicide in control of gray mold and, at least two weekly applications of Cr are required for a successful gray mold management. We studied the integration of biological control (CR) by Cr, removal of crop debris (DE), and fungicide sprays (FS) to manage gray mold. In both years, LAC was higher in the treatments with no FS. Most reductions of ANC were with CR (92.01%), CR + DE (94.80%), and CR + DE + FS (96.62%). Iflower was most reduced with application of CR (68.48%), CR + FS (67.82%), CR + DE (77.58%), and CR + DE + FS (86.54%). IFruit was most reduced with FS + DE (69.20%), CR (65.33%), CR + CD (76.47%) and CR + DE + FS (83.64%). Yield was most increased with CR (75.15%), CR + FS (78.39%), CR + DE (79.83%) and CR + DE + FS (103.14%). The most efficient method to manage Bc was biocontrol, that when associated to the other methods increased efficiency in reducing gray mold intensity. Thus the use of CR is a key strategy to manage gray mold of strawberry. We also studied dispersal gradients of both Bc and Cr, in independent experiments. Inoculum sources for Cr were wheat grains colonized and ground and for Bc were strawberry fruits and stems with pathogen sporulation. Each source was set in the center of 10 m or 20 m-length plots for Cr and Bc, respectively, and weekly until the harvest we assessed several variables at each 30 cm distance, at both downwind and upwind directions from the sources. For Cr, we quantified LAC, and the maximum distances the antagonist reached were 45 and 105 cm, at upwind and downwind directions, respectively. For Bc, we evaluated ANC, IFlowers and IFruits. At all evaluations, the three variables were higher closer the source. At the last evaluation (104 days after planting), diseased leaves, flowers and fruits were detected up to 975 cm from the source. Gray mold gradients in flowers and fruits flattened, but gradients in leaves did not. Wind direction had no effect on Bc dispersal. Crop debris are important inoculum source for gray mold epidemics. Bc was efficient in dispersing under field conditions whereas Cr was not.