Resumo

VASQUEZ-LOPEZ, Alfonso; MORA-AGUILERA, José A.; CARDENAS-SORIANO, Elizabeth  e  TELIZ-ORTIZ, Daniel. Etiology and histopathology of dieback disease on mamey trees (Pouteria sapota (Jacq.) H. E. Moore and Stearn) in Guerrero, Mexico. Agrociencia [online]. 2009, vol.43, n.7, pp.717-728. ISSN 2521-9766.

In Alpoyeca, Guerrero, México, dieback on mamey trees (Pouteria sapota) is a disease of unknown etiology that reduces productivity and longevity of commercial orchards. In this study the etiology of the disease and anatomic damage it causes to branches were determined. From symptomatic branches, Lasiodiplodia sp. was consistently isolated, and its pathogenicity was verified on mamey branches with epidermis and peridermis (with and without lesions). After 30 d, the fungus produced necrotic lesions on branches with peridermis inoculated through wounds, and in 24 months it induced dieback of vegetative shoots. The control branches remained asymptomatic. The anatomical damage on symptomatic branches included peridermis rupture, collapse and necrosis of cortical, phloem, and laticifetous cells, and external phloem fibers and vasculat cambium. In the phloem, crystals and granular precipitates formed; the radial and the axial parenchyma lignified, and sclereids formed. The xylem and medulla were not damaged. Based on its motrphological and molecular characteristics, the fungus that induced dieback on mamey trees in Alpoyeca, Guerrero, was Lasiodiplodia theobromae. The genetic sequence of the pathogen was deposited in the gene bank (NCBI) with access number EU564805.

Palavras-chave : Lasiodiplodia theobromae; Histopathology; dieback; mamey sapote.

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