Abstract

MORALES-GARCIA, José Luciano et al. Morpho-molecular identification of the causal agent of avocado scab in Michoacán. Rev. mex. fitopatol [online]. 2023, vol.41, n.2, pp.182-202.  Epub Aug 11, 2023. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.2302-4.

Mexico is the main producer and exporter of avocado (Persea americana) in the world; however, pests and diseases are limiting factors for production. One of the diseases of great economic importance is avocado scab, which is characterized by causing corky-looking lesions on the epicarp of the fruits, which decreases quality and price by up to 60%. In this study, a sampling was carried out aimed at avocado fruits with damage in the epicarp with a corky appearance, these commonly known in the field as “scab” and “purple spot”. For molecular and phylogenetic identification, a combination of techniques with morphological keys and molecular markers (ITS1/ITS4, ITS5/ITS4, FE-1α/EF-1α, Sph1 F/Sph1R) was used. Pathogenicity tests were also carried out on fruits in plants of Hass, Flor de María and Méndez varieties. Through morphological analysis, fungi of the genera Colletotrichum, Pestalotiopsis and Elsinoe were identified. Molecular identification and phylogenetic analysis confirmed the presence of the species Colletotrichum gloeosporioides and Elsinoe perseae. C. gloeosporioides reproduced symptoms similar to the avocado scab disease. With the strain identified as E. perseae, the symptom known in the field as purple spot was confirmed, while Pestalotiopsis sp. caused descending necrosis.

Keywords : Persea americana; Elsinoe perseae; Colletotrichum gloeosporioides; purple spot.

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