First aeromycological study in an avocado agroecosystem in Mexico

Avocados (Persea americana Mill.) are economically and nutritionally valuable despite their susceptibility to several fungal diseases. This study was conducted in an agroecosystem of avocado trees in México. The air samples were collected every week by gravimetric methods at a height of 2 m from the ground level. Fungal colonies were isolated and transferred onto PDA and identified using morphological methods. During air sampling, different meteorological variables were measured. The symptoms of avocado diseases were determined by visual observations. To the best of our knowledge, this is the first study on aeromycological characterization in an avocado agroecosystem. Thirty-two airborne fungal genera were identified; Fusarium (97.2 %) and Colletotrichum (94.4 %) were the most common fungal pathogens present in the atmosphere of avocado. In addition, seven genera of important phytopathogenic fungi of other crops (Alternaria, Capnodium, Pestalotia, Stemphylium, Rhizopus, Curvularia, and Phyllachora) were isolated. The maximum concentration of total fungi was observed in June (358 CFU m⁻³) and the minimum in September (83 CFU m⁻³). The total fungal concentrations were significantly negatively correlated with the temperature. The symptoms of five diseases of avocado, viz. anthracnose, scab, spot, canker trunk, and vascular wilt, were identified in the area study. It was observed that the symptoms of all the above-mentioned diseases were present in June; and in the same month, the fungal concentrations were highest.