First Occurrence of Powdery Mildew Caused by Leveillula taurica on Pepper in New York

Powdery mildew was observed for the first time on pepper (Capsicum annuum L.) in western New York in August 1999 and on Long Island, NY, in August 2000. Infected plants were found in commercial fields planted with transplants from Georgia and Florida. Powdery mildew was not found in nearby commercial fields in either year, and it was not found in 2000 in western New York. Symptoms included white sporulation on the undersurfaces of leaves, causing yellow lesions on upper surfaces that turned necrotic and led to premature defoliation. The pathogen was confirmed to be Leveillula taurica (Lév.) G. Arnaud, a species complex that infects more than 1,000 plant species in 74 families, including pepper, tomato and eggplant. Only the Oidiopsis stage was found. Conidia were 47.3 to 74.3 μm × 10.5 to 20.3 μm (average 64.0 × 16.8 μm (N = 71). Symptoms were observed on all cultivars of bell and chili pepper in the Long Island field but not on tomato (Lycopersicon esculentum) and eggplant (Solanum melongena var. esculentum) in adjacent rows. Powdery mildew of pepper was first observed in North America in 1971 in southwest Florida (1). Symptoms were found on field-grown peppers in Florida in April 2001 at the time that transplants were being produced for New York. Considering the latent period is 18 to 21 days and symptoms tend to be initially subtle, diseased seedlings could easily go undetected. This disease is a problem on tomatoes and peppers in California (2), Arizona, Utah, and Nevada. Powdery mildew of pepper was reported in Puerto Rico in 1992, in Idaho on greenhouse-grown pepper in 1998, in north-central Mexico in 1998, and in both Canada and Oklahoma on greenhouse-grown pepper in 1999. Powdery mildew of peppers has not been seen in Connecticut, Massachusetts, New Jersey, North Carolina, or Ohio. References: (1) C. H. Blazquez. Phytopathology 66:1155, 1976. (2) R. F. Smith et al. Calif. Agric. 53:40, 1999.