Avaliação de quitosana, aplicada em pós-colheita, na proteção de uva 'Itália' contra Botrytis cinerea
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Data
2007-09-01
Autores
Camili, Elisangela Clarete [UNESP]
Benato, Eliane Aparecida
Pascholati, Sérgio Florentino
Cia, Patrícia
Título da Revista
ISSN da Revista
Título de Volume
Editor
Grupo Paulista de Fitopatologia
Resumo
Perdas significativas ocorrem durante o armazenamento e a comercialização de uvas de mesa devido, principalmente, à ocorrência do mofo cinzento (Botrytis cinerea Pers.:Fr.) e, para o controle de patógenos emprega-se, geralmente, o dióxido de enxofre (SO2). Diante da restrição crescente ao uso de produtos químicos em pós-colheita, tem ocorrido considerável interesse em métodos alternativos de controle. Este trabalho teve como principal objetivo avaliar os efeitos da quitosana, na proteção pós-colheita de uva 'Itália' contra B. cinerea. In vivo, avaliou-se o efeito direto e indireto da quitosana pelo tratamento dos cachos de uva, antes e após a inoculação com o patógeno. Utilizou-se quitosana nas concentrações de 0,00; 0,25; 0,50; 1,00; 1,50 e 2,00 % (v/v). Para inoculação, em 10 bagas de cada cacho de uva foram feitos ferimentos de ±2 mm de profundidade, procedendo-se em seguida, a aspersão da suspensão de conídios (±10(5) conídios.mL-1) de B. cinerea. Após os tratamentos, os cachos foram mantidos a 25±1 °C / 80-90 % UR e avaliados diariamente quanto à incidência e severidade da podridão. Avaliações in vitro do efeito do produto sobre o patógeno também foram realizadas analisando-se o crescimento micelial e a germinação dos conídios de B. cinerea. A solução de quitosana, nas concentrações de 1,5 e 2,0 % (v/v), quando empregada após a inoculação com B cinerea, reduziu significativamente o índice de doença no entanto, quando os cachos foram tratados antes da inoculação, não houve efeito significativo do tratamento sobre o desenvolvimento da doença. Nos ensaios in vitro, a solução de quitosana, nas maiores concentrações, suprimiu o crescimento micelial do patógeno e retardou a germinação dos conídios.
Significant losses of table grapes are seem during storage and marketing due mainly to the occurrence of gray mold (Botrytis cinerea Pers.:Fr.), whick has been frequently controlled by using sulfur dioxide (SO2). Due to increase in restrictions on the postharvest use of chemical products, considerable interest in alternative control measures has arise. The main objective of this study was to evaluate the effects of chitosan in 'Itália' grapes, aimed at post-harvest protection against B. cinerea. The direct and indirect effects of chitosan were evaluated in vivo by treating bunches of grapes before and after inoculation with the pathogen. Chitosan was used in the concentrations of 0.00; 0.25; 0.50; 1.00; 1.50 and 2.00 % (v/v). For inoculation, 10 grapes in each bunch were injured by piercing the grape to a depth of ±2 mm, followed spraying with B. cinerea conidia (± 10(5) conidia.mL-1). After the treatments, the bunches were kept at 25±1°C/80-90% RH. Disease incidence and severity evaluations were carried out daily. In vitro evaluations regarding the effect of the product were also carried out based upon mycelial growth and germination of B. cinerea conidia. When applied after inoculation with B. cinerea, 1.5 and 2.0 % (v/v) solutions of chitosan significantly reduced the occurrence of the disease, although when applied before inoculation there was no significant effect on the development of the disease. The higher concentrations of chitosan suppressed mycelial growth of the pathogen and delayed conidium germination.
Significant losses of table grapes are seem during storage and marketing due mainly to the occurrence of gray mold (Botrytis cinerea Pers.:Fr.), whick has been frequently controlled by using sulfur dioxide (SO2). Due to increase in restrictions on the postharvest use of chemical products, considerable interest in alternative control measures has arise. The main objective of this study was to evaluate the effects of chitosan in 'Itália' grapes, aimed at post-harvest protection against B. cinerea. The direct and indirect effects of chitosan were evaluated in vivo by treating bunches of grapes before and after inoculation with the pathogen. Chitosan was used in the concentrations of 0.00; 0.25; 0.50; 1.00; 1.50 and 2.00 % (v/v). For inoculation, 10 grapes in each bunch were injured by piercing the grape to a depth of ±2 mm, followed spraying with B. cinerea conidia (± 10(5) conidia.mL-1). After the treatments, the bunches were kept at 25±1°C/80-90% RH. Disease incidence and severity evaluations were carried out daily. In vitro evaluations regarding the effect of the product were also carried out based upon mycelial growth and germination of B. cinerea conidia. When applied after inoculation with B. cinerea, 1.5 and 2.0 % (v/v) solutions of chitosan significantly reduced the occurrence of the disease, although when applied before inoculation there was no significant effect on the development of the disease. The higher concentrations of chitosan suppressed mycelial growth of the pathogen and delayed conidium germination.
Descrição
Palavras-chave
Vitis vinifera L., mofo cinzento, indução de resistência, controle, Vitis vinifera L., gray mold, induced resistance, control
Como citar
Summa Phytopathologica. Grupo Paulista de Fitopatologia, v. 33, n. 3, p. 215-221, 2007.