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Knowledge of the health condition of urban trees is fundamental for making decisions regarding management and resource allocation. The objective of this study was to determine the current health status of the trees at the National Institute of Astrophysics, Optics, and Electronics (INAOE) in San Andres Cholula, Mexico. Five health indicators previously used in urban forests were assessed. The structure and diversity indicator indicated the existence of 2210 trees, mostly (58.8 %) of small size (< 20 cm average diameter at breast height), 20 botanical families, and 32 tree species. The crown condition and its variables indicated high foliage transparency (> 40 %) in some of its species and low percentages of dieback. Live crown ratio and crown density were moderate in eight and six species, respectively. The tree damage indicator showed the existence of 44 damaging agents in 956 trees (43.3 % of the total), highlighting the ball moss (Tillandsia recurvata), the felt fungus of evergreen ash (Septobasidium sp.) associated with an armored scale, the same fungus also affecting white cedar (Hesperocyparis lusitanica) in association with another scale (a new record), and two bark beetles, Hylesinus aztecus in evergreen ash, and Phloesinus sp. in white cedar. Regarding the mortality indicator, 75 trees (3.3 %) were recorded. Finally, the soil condition indicated that the pH was close to neutral, with electrical conductivity values above 2 dS m-1 and a low beneficial mycoflora population. All these factors, together with the imbalance in tree diversity, high planting density, compacted soils, and the presence of risky trees, are negatively affecting the health of INAOE's tree community. [ABSTRACT FROM AUTHOR]

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The decline and death of palms (Phoenix canariensis) in Mexico City is a problem that has increased in the last five years, causing the death of more than 500 palms and others with different degrees of damage. The causal agent has not been determined, so the present study aimed to identify the associated fungi of the decline and death of palms (Phoenix canariensis) in Mexico City. From February to August 2022, samples of symptomatic plant tissue from the trunk, petiole, rachis, and leaflets were collected at nine representative sampling sites in seven Boroughs of Mexico City. A total of 144 fungal isolates were obtained, comprising 11 different species. The species with the highest frequency were: Nalanthamala vermoesenii, Lasiodiplodia sp., Neopestalotiopsis sp., and Serenomyces sp., present mainly on the petiole and rachis; and Alternaria alternata and Phoma glomerata in the leaflets, these species have been reported as causative agents of different diseases in other countries and are reported for the first time in Mexico associated with P. canariensis. The information generated will allow establishing management measures tending to reduce the death of palms. [ABSTRACT FROM AUTHOR]

To identify the agent of black scab on prickly pear (Opuntia ficus-indica), the fungi associated with the disease were isolated and morphologically identified. The study was carried out from cladodes with characteristic symptoms of the disease collected in the town of Santa Cecilia Clavijero, in the municipality of San Juan Ixcaquixtla, Puebla. The fungi associated with the disease were identified as: Cladosporium cladosporioides, Aplosporella hesperidica and Didymella glomerata. To demonstrate their pathogenicity, the fungi were inoculated individually and in their combinations in six-month-old cladodes. Symptoms started 50 days after inoculation. The inoculation method that allowed the reproduction of the symptoms was the injection of a suspension at a concentration of 6 × 10³ conidia mL-1 of the mixture of the three fungi; cladodes inoculated with one and two fungi, did not result in the development of the disease. C. cladosporioides, A. hesperidica and D. glomerata are the causative agents of the nopal black scab, this being the first report of these pathogens in the nopal cultivation. [ABSTRACT FROM AUTHOR]