Fungal Biocontrol for the Ascochyta Blight

Ascochyta blight, caused by the fungus Ascochyta rabiei, is one of the most devastating diseases of chickpea. The fungus attacks all above-ground parts of the host. During the winter, A. rabiei survives on chickpea stubble and forms sexual spores, called ascospores, which can infect plantings of the crop in the spring. Symptoms include necrotic spots in leaves, leading to severe defoliation, stems and pods. Severe outbreaks, fueled by cool, wet conditions, can wipe out the entire crop.

Now researchers from the U.S. Department of Agriculture's Agricultural Research Service (ARS) have identified another fungus that could be used to control A. rabiei. Frank Dugan and colleagues isolated Aureobasidium pullulans strains that inhibit A. rabiei's ability to form or release ascospores, thereby curbing its infection of chickpea seedlings. ARS noted that although there exist other ways to control the blight, such as treating chickpea seeds with fungicides, planting resistant varieties, plowing crop fields before planting time, and rotating chickpeas with non-host crops, biocontrol is worth exploring for its potential to provide chickpea growers with greater flexibility in how they manage the disease.

Field trials showed that treating chickpea stubbles with A. pullulans spores reduced Ascochyta blight by 38 percent. The ARS scientists expect that this can be improved using adjuvants and other standard ingredients often used in biocontrol formulations.

Read the original story at http://www.ars.usda.gov/is/pr/2009/091204.htm