Post-harvest citrus diseases: Potential of the Lentinula edodes, Agaricus blazei, jasmonic acid, mesocarp (Citrus sinensis var. Valência) and epicarp (Citrus aurantifolia var. Tahiti) in the control and in the resistance induction / Doenças pós-colheita em citros: potencial do Lentinula edodes, Agaricus blazei, ácido jasmônico, albedo (Citrus sinensis var. Valência) e flavedo (Citrus aurantifolia var. Tahiti) no controle e na indução de resistência

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Brazil is considered the biggest citrus producer and the biggest orange juice exporter. Post-harvest diseases represent a great loss in the citriculture, and for many fruits to be exported they should be free of chemical residues. In relation to some pathogens of importance in post-harvest it can be mentioned Guignardia citricarpa (black-spot-ofcitrus), Penicillium digitatum (green-mold) and Colletotrichum gloeosporioides (anthracnose). Because of the economical importance that represents this disease complex in citric fruits, in terms of compromising fruit quality, limitations to the exports and control difficulties, the search for alternative control measures that can make possible improve the producing capacity of the producers and the obtaining of fruits with excellent quality are indispensable. Thus, in this context it can be included measures of alternative control that do not include the chemical control. Under this point of view, control include the use of biotic and abiotic agents and the resistance induction in plants. Therefore, it was studied the viability of the control of post-harvest diseases in citrus, involving the direct action on the patogens by using ethanolic extracts of albedo (mesocarp) of sweet orange (Citrus sinensis var. Valência) and flavedo (exocarp or epicarp) of lemon-Tahiti (Citrus aurantifolia Swing var. Tahiti). The results showed that the extract of the albedo exhibited antifungal activity on G. citricarpa and the flavedo of the "Tahiti" lemon on C. gloeosporioides, and it was also demonstrated the existence of volatile compounds toxic to the fungus. The second part involved the control and resistance induction in the fruits, by using the biotic agents Lentinula edodes and Agaricus blazei and the abiotic agent jasmonic acid. It was possible to observe that the aqueous extracts from the albedo (C. sinensis), flavedo (C. aurantifolia), L. edodes and A. blazei reduced the formation of new lesions caused by G. citricarpa, however they did not exhibit effects on P. digitatum and C. gloeosporioides in fruits of C. sinensis var. Valência when treated in post-harvest. Thus, in the present work it was demonstrated the viability of possible alternative control measures of diseases in post-harvest of citrus, indicating the need of looking for new agents to act as resistance inducers or agents to directly control on the phytopathogens.

ASSUNTO(S)

mancha-preta-dos-citros phytopathogenic fungi antracnose doença de planta anthracnose fruta cítrica pós-colheita post-harvest citric fruit plant disease black spot of citrus fungo fitopatogênico green-mold bolor-verde-dos-citros

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