Division of Plant Pathology and Microbiology in Plant Sciences Department
Research project:

Biocontrol of Sclerotinia sclerotiorum in desert-grown winter lettuce

In winter, over 90% of all US lettuce production occurs in the deserts of Arizona and California, and is a critical industry for this region's economic health. The fungal disease lettuce drop, caused by Sclerotinia sclerotiorum , is a key factor limiting production in desert winter lettuce. Effective management strategies are few, and growers rely primarily on chemical fungicides to treat over 70% of all lettuce fields. Preliminary data suggests that the biocontrol agent Coniothyrium minitans can provide a level of control far superior to that of current fungicides. The objectives of this project are to: 1) determine the soil density of Sclerotinia and distribution patterns in desert lettuce production fields; 2) establish the relationship between Sclerotinia density and disease for the 3 lettuce types under different cultural and environmental conditions; 3) comprehensively evaluate the efficacy of C. minitans under different Sclerotinia densities, environmental conditions, and cultural practices. Results from these studies will enable the development of a lettuce drop risk assessment program and recommendation guidelines for improved lettuce drop management in desert production of crisphead, romaine, and leaf lettuce.

For more information: Dr. Barry Pryor, bmpryor@u.arizona.edu
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