Background/Objective.

In recent years, a phytopathological problem has manifested itself in avocado cultivation whose etiology is unknown, this disease is known as peduncle ringing, mainly affects fruits of the cv. Hass. The objective of this research was to determine the etiological agent involved in the development of the disease.

Materials and Methods.

A collection of avocado fruits was carried out with characteristic symptoms of peduncle ringing: brown peduncle and reddish to purple coloration in the pericarp, the collections were made in the municipalities of Coatepec Harinas, Donato Guerra and Malinalco State of Mexico. In the laboratory, fungi were isolated in PDA medium. Three species of fungi were identified by morphological analysis and confirmed at the DNA level by PCR. Pathogenicity tests were performed on the three species identified individually and in combinations. The variables evaluated were incidence, severity, days at symptom manifestation and percentage of fruits with damaged mesocarp.

Results.

Fungi associated with peduncle ringing damage in avocado fruits cv. Hass were identified as Alternaria tenuissima, Cladosporium cladosporioides and Epicoccum nigrum. A. tenuissima showed its high pathogenic capacity to induce peduncle ringing in avocado fruits with 100% incidence and 40% severity. It should be noted that the data on incidence, severity and mesocarp damage are higher in treatments when A. tenuissima, C. cladosporioides and E. nigrum act independently than in consortia.

Conclusion.

A. tenuissima, C. cladosporioides and E. nigrum inoculated independently and in consortia were shown to replicate the symptoms of ringing: peduncle in brown-colored fruits and reddish to purple coloration on the pericarp and the mummification of fruits.

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