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

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