Antifungal activity and ultrastructural alterations in Pseudocercospora griseola treated with essential oils

Ciência e Agrotecnologia

Julián Mauricio Ágredo Hoyos²  Eduardo Alves¹  Luciane Cristina Rozwalka¹  Elaine Aparecida De Souza¹  Walmes Marques Zeviani¹ 

[1],Universidade Federal de Lavras Departamento de Fitopatologia Lavras MG ,Brasil

关键词: Angular leaf spot;    transmission electron microscopy;    alternative control of plant disease;    Mancha angular;    microscopia eletrônica de transmissão;    controle alternativo de doenças de plantas;   

DOI  :  10.1590/S1413-70542012000300002

来源: SciELO

【 摘 要 】

Pseudocercospora griseola, the etiologic agent of angular leaf spot of common bean (Phaseolus vulgaris), is an important disease in all bean-producing regions worldwide and may cause extremely high yield losses. The control of this disease is made more difficult by the pathogen's genetic variability and the inefficiency of fungicides. In this study, of 26 essential oils tested at different concentrations, 25 demonstrated efficiency in affecting the germination of strains 63-31 and 63-63 of the pathogen, reaching inhibition levels of between 80% and 100%. Cymbopogon citratus and Cymbopogon martinii inhibited conidia germination at all concentrations; Eugenia caryophyllata, Cinnamomum sp., Thymus vulgaris, Matricaria recutita, Cordia verbenacea, Origanum vulgare, Cymbopogon nardus, at 0.1 and 0.5%; and Zingiber officinale, Mentha arvensis, Chamaecyparis pisifera, Lavandula officinalis, Ocimum basilicum, Pimpinella anisum, Ocimum selloi, Baccharis dracunculifolia, Laurus nobilis, Citrus sinensis, Melaleuca alternifolia and Eucalyptus globulus, at 0.5%. The main constituents identified were cinnamaldehyde in Cinnamomum sp.; eugenol in E. caryophyllata; trans-β-farnesene in M. recutita; pulegone in C. verbenacea; thymol in T. vulgaris; geranial and neral in C. citratus, and geraniol in C. martini. Through transmission electron microscopy (TEM), it was verified that C. citratus, C. martini and E. caryophyllata presented direct fungitoxic action on P. griseola, causing severe damage to the cellular ultrastructure of the conidia, invalidating germination. These results indicated that essential oils are a promising alternative strategy for the control of angular leaf spot in bean, representing less risk to human health and the environment.

【 授权许可】

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