No abstract

Maize is the main crop for Mexicans; however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some agronomic variables of four maize genotypes. The seeds of the genotypes H-515, Zapata 7, and H-507 were treated with a suspension of Trichoderma spp. to 1 × 10 8 spores mL −1 , using a control (untreated seed), and Benomyl as chemical control. The planting was in Morelos, in a completely random block design with a factorial arrangement. The ear rot was natural. Data were obtained at the end of the crop cycle and processed in SAS 9.4 ® . H-515 genotype had the greatest effect on the treatment of maize seeds with Trichoderma spp. (5.562 kg); T. asperellum T11 was the strain that stood out with a mean yield of 50 ears in an area of 16 m 2 of 4.904 kg, and control of 4.448 kg. Our results are an economic option for farmers to contemplate the use of Trichoderma and obtain its benefits.

The objective of the research was to identify the fungi in sotol seeds at different conditions of temperature and relative humidity. Seeds were collected at Buñuelos, municipality, and taken to the Laboratory of the Center for Training and Development in Seed Technology (CCDTS) at Universidad Autonoma Agraria Antonio Narro. The seed was stored for a period of 90 days, whit conditions of 60, 75, 80 and 85% of relative humidity kept at 5, 15 and 25 °C. Fungi identifying by morphological criteria. A completely randomized experiment using R software, with factorial arrangement whit two replications. Pathogens identified were: Aspergillus glaucus, Aspergillus niger, Fusarium sp., Penicillium sp., Aspergillus candidus, Cladosporiun sp., Alternaria sp. and Aspergillus chraceus, the results showed that the higher the humidity, temperature and storage time, the incidence of fungi tends to be higher. Fungi with a higher presence in sotol seeds were: Aspergillus glaucus and Penicillium sp. Safe storage environments for sotol seeds reported in this work are 5 °C and a relative humidity of 60-75%. Sotol seeds tolerates conditions of 15 °C and a relative humidity up to 75%.

The objective this research was identify the fungi associated with the Chenopodium album leaf spot. Samplings were carried out at Universidad Autonoma Agraria Antonio Narro in a manner directed towards the weeds (10 plants) that showed signs and symptoms of this disease (pycnidia and a yellow halo on the leaves) and were later taken to the phytopathology laboratory for isolation and identification. The weed identified by morphological criteria. Pathogen was identified by morphocultural of 100 conidia criteria using AxioVision Release 4.5 software. The purification of the isolates was performed by hypha tip in PDA. Macrophoma sp. was identified damaging the weed C. album whit conidia ellipsoidal to subglobose, of 18.21 µm length and 2.56 µm width. Therefore a future investigation of this pathogen and host is recommended.

El nogal negro americano (Juglans nigra L.) es afectado por problemas fitosanitarios, destacando hongos causantes de cancros en ramas, reduciendo la producción de fruto hasta 60% del rendimiento promedio que es 1.9 t ha-1. Los objetivos de esta investigación fueron identificar los hongos asociados a cancros presentes en ramas de árboles de J. nigra con síntomas de muerte descendente y evaluar su patogenicidad. Se aislaron hongos de cancros de ramas con síntomas de muerte descendente colectadas en dos huertas del estado de Coahuila. Cuatro morfotipos de hongos fueron obtenidos y una cepa de cada uno se utilizó para su identificación morfológica a nivel de género, y mediante la secuenciación de la región ITS1 a ITS2 de los genes ribosomales (rDNA) para su identificación a nivel de especie. Las pruebas de patogenicidad se realizaron en plántulas de J. nigra de cuatro meses de edad, realizando una fisura en el tallo de 3 mm de largo e inoculando con cada especie identificada. Los hongos asociados a los cancros de J. nigra fueron identificados morfológicamente como miembros de los géneros Trichothecium, Pestalotiopsis, Alternaria y Rhizoctonia. Mediante el análisis BLAST en el GenBank de las secuencias de la región ITS1 a ITS2 fue posible determinar que las cepas se encontraron relacionadas a las especies Trichothecium roseum, Pestalotiopsis steyaertii, Alternaria alternata y a una especie binucleada no determinada de Rhizoctonia. La inoculación de las cuatro cepas a plántulas demostró que éstas son patogénicas a J. nigra.