Abstract

DE LA TORRE-ALMARAZ, Rodolfo et al. Etiology of mesquite dieback (Prosopis laevigata L.) in the biosphere reserve of Zapotitlan Valley, Mexico. Agrociencia [online]. 2009, vol.43, n.2, pp.197-208. ISSN 2521-9766.

During 2001, branch dieback (Prosopis laevigata L.) was observed on mesquite plants in the Tehuacan-Cuicatlán biosphere reserve, Puebla, México (18° 15' N and 97° 25' W). Developing on damaged branches was a light brown fungus tissue that produced conidiophores and hyaline conidia, greenish in mass, ellipsoid with one truncate tip and glomerate to pulvinate stromata with conspicuous perithecial mounds, black surface, and globose perithecia. Ascospores were dark-brown, single-celled, non-equilateral ellipsoid with rounded tips and a germination tube along the spore. Perispores were dehiscent in 10 % KOH and had coiled, smooth epispore. The fungus was identified as Hypoxylon diatrypeoides Rehm and its anamorph as a Nodulosporium-type species. Branch dieback symptoms were induced in mesquite plants produced in a greenhouse by inoculating branches with a wooden toothpick colonized with fungus mycelia and perthecia and inserted through a permanent wound. Symptoms appeared 15 days after the inoculation. The nucleotide sequence of the ITS1-ITS2 region of this H. diatrypeoides isolate from México (Accession No. AY303629) confirmed that taxonomically it belongs to the Xilareaceae family and was related to species previously reported only in South America and South Asia.

Keywords : Wild plant pathosystems; arid lands; xylariales.