First Report of Powdery Mildew (Pseudoidium anacardii) of Mango Trees in Sinaloa, Mexico

Abstract

Powdery mildew of mango is an important disease in Mexico's northern Sinaloa state. Identification of the causal fungal agent has been hindered by the absence of information regarding its teleomorph, as well as a detailed morphometric analysis of the anamorph and molecular characterization. The first symptoms of the disease appear in mango inflorescences of early February, and it subsequently affects young fruits. The disease progresses during March and early April, causing significant fruit abortion and a scabby appearance in a high percentage of fruits that remain attached to the trees. We observed the disease on inflorescences but not in leaves during our sampling period. Powdery mildew specimens were collected during 2011 and 2012 and included Kent and Keith varieties from commercial orchards, and creole materials from backyards of private residences in the Ahome and Fuerte Counties of northern Sinaloa, Mexico. Symptomatic inflorescences were analyzed morphologically. Conidiophores and conidia were prepared by touching the whitish lesions with clear adhesive tape, which was then placed over microscope slides with a drop of distilled water and observed under a compound microscope. The anamorph structures of the pathogen were measured. The mycelium was septate and ramified on the surface of the host, forming a dense coat of branching hyphae. The mycelium had a diameter of 2.5 to 8.7 μm; conidiophores (Pseudoidium type) emerged from the superficial mycelium, were unbranched, and consisted of 1 to 3 cells with conidia forming singly from the apex. The length of the conidiophores varied from 30.0 to 77.5 μm; the foot cell of the conidiophores was straight, 10.0 to 47.5 μm long and with a diameter of 5.0 to 15.5 μm across its midpoint. Conidia without fibrosin bodies were borne singly, and were ellipsoid/ovoid, 22.5 to 46.2 μm long and 15.0 to 27.5 μm wide. Eighty percent of the germ tubes were forked (lobed); the rest were simple, emerged from the end, and were occasionally on the side of the conidia. Germ tubes ranged from 2.0 to 7.2 μm at the midpoint. The surface of the conidia appeared smooth under the scanning electron microscope, and elliptical conidia appeared constricted at their ends; this, however, was not observed in the ovoid conidia. In both cases, the terminal end of the conidia was smooth. The teleomorph was not found. Molecular and phylogenetic analysis of the ITS rDNA (2) region showed that samples are closely related to specimens of Pseudoidium anacardii (1) (teleomorph: Erysiphe quercicola [4]) collected from mango trees in diverse countries. Measurements of somatic and asexual structures are in agreement with descriptions of P. anachardii (formerly known as Oidium mangiferae) from India (3). The nucleotide sequences derived from this research were deposited in GenBank (Accession Nos. JX893951 to JX893957). To our knowledge, this is the first report of P. anacardii associated to mango inflorescences in Sinaloa, Mexico. Due to the economic importance of powdery mildew of mango trees in Sinaloa, future research directions should focus on finding the teleomorph of the fungus to support its identity. References: (1) U. Braun and R. T. A. Cook CBS Biodiversity Series No. 11, 2012. (2) S. Limkaisang et al. Mycoscience 47:327, 2006. (3) O. Prakash and K. C. Srivastava. Mango diseases and their management. A World Review Today and Tomorrow Publishers. New Delhi, India, 1987. (4) S. Takamatsu et al. Mycol. Res. 111:809, 2007.

Las cenicillas en cultivos agrícolas de Sinaloa: Situación actual sobre su identificación y líneas futuras de investigación

“…Cook with E. quercicola as a teleomorph (Félix-Gastélum et al, 2013). As in other mangoproducing areas of the world (Nasir et al, 2014), in northern Sinaloa the teleomorph was not found in specimens collected in mango vars.…”

“…As in other mangoproducing areas of the world (Nasir et al, 2014), in northern Sinaloa the teleomorph was not found in specimens collected in mango vars. Kent and Keith in commercial or backyard orchard trees (Félix-Gastélum et al, 2013). In other parts of…”

“…Con base en estudios morfométricos, imágenes de conidios al microscopio electrónico de barrido (Figura 4 A y B), así como estudios moleculares y análisis filogenéticos del anamorfo, se determinó que el agente causal de la enfermedad en Sinaloa es Pseudoidium anacardii (F. Noack) U. Braun y R.T.A. Cook con E. quercicola como teleomorfo (Félix-Gastélum et al, 2013). Al igual que en otras zonas productoras de mango en el mundo (Nasir et al, 2014), en el Norte de Sinaloa no se encontró el teleomorfo en especímenes colectados en mango vars.…”

“…Al igual que en otras zonas productoras de mango en el mundo (Nasir et al, 2014), en el Norte de Sinaloa no se encontró el teleomorfo en especímenes colectados en mango vars. Kent y Keith en árboles de huertas comerciales y de traspatios (Félix-Gastélum et al, 2013). En otras partes del mundo el hongo inverna como micelio o haustorios en yemas o puede permanecer en el follaje denso de los árboles (Nasir et al, 2014); between relative humidity, temperature and the phenology of the host with the severity of the disease.…”

Respuesta de diez cultivares de mango amarillo al daño por cenicilla (Erysiphe quercicola) en México

“…Mango powdery mildew caused by Erysiphe quercicola (anamorph: Pseudoidium anacardii) (Braun and Cook, 2012;Félix et al, 2013;Tam, 2017) is one of the most important diseases that affects mango because of its high level of severity, endemism and cosmopolitan distribution (Raheel et al, 2008) La cenicilla del mango, causada por Erysiphe quercicola (anamorfo: Pseudoidium anacardii) (Braun y Cook, 2012;Félix et al, 2013;Tam, 2017) es una de las enfermedades más importantes de este frutal por su alta severidad, endemismo, distribución cosmopolita (Raheel et al, 2008) y causar pérdidas de cosecha de 80-90% (Gupta, 1989b;Shoeman et al, 1995;Nasir et al, 2014). En entidades federativas exportadoras de mango como Michoacán puede afectar el 60% de los árboles comerciales, representando 30-50 mil ton de fruta (Arias et al, 2004) y en Sinaloa ocasionar pérdidas de 70% durante floración (Félix et al, 2017).…”