Chitosan reduces infection by Guignardia citricarpa in postharvest 'Valencia' oranges

Brazilian Archives of Biology and Technology

Maria Cristina Canale Rappussi²  Sérgio Florentino Pascholati²  Eliane Aparecida Benato¹  Patrícia Cia¹ 

[1],Escola Superior de Agricultura Departamento de Entomologia

[2] Fitopatologia e Zoologia Agrícola Piracicaba SP ,Brasil

关键词: Black spot;    citrus fruit;    alternative control;    resistance induction;   

DOI  :  10.1590/S1516-89132009000300001

来源: SciELO

【 摘 要 】

Citrus fruits are affected by the black spot disease caused by Guignardia citricarpa. Resistance induction is an alternative control measure and chitosan exhibits potential as resistance inducer. The effect of chitosan on G. citricarpa was evaluated in vitro and in 'Valencia' oranges. Citrus fruit were immersed into different chitosan concentrations. Chitosan (2%), combined with or without thiabendazole and the citric acid was also investigated. All the chitosan concentrations inhibited G. citricarpa mycelial growth and affected morphologically the conidial germination and appressorium formation. Chitosan inhibited the development of new lesions in oranges at room condition or under refrigeration. Thiabendazole and citric acid did not reduce the formation of lesions. Biochemical analysis revealed that chitinase, β-1,3-glucanase, peroxidase and polyphenoloxidase activities were increased in chitosan-treated fruits. Thus, the effect of chitosan on the reduction of black spots in 'Valencia' oranges could be due to the germicidal effect on the pathogen and/or resistance induction in the fruit.

【 授权许可】

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