Thresholds for Net Blotch Infestation in Organic Barley Seed Production

Net blotch-infested seeds can be as important as initial inoculum source for net blotch epidemics as other inoculum sources such as infected straw. Our results underline the importance of varietal resistance for seed health. Employing resistant varieties results in low net blotch severity levels in the field which in turn reduces the risk of seed infestation. The results give reason to assume that the present threshold recommendations for seed born barley net blotch could be raised for normal growing conditions and/or for varieties having a reasonable level of net blotch resistance. Supplemental results are expected from ongoing field trials and more detailed analyses will follow to improve our understanding of quantitative relationships among epidemiological key variables to develop decision support tools for handling net blotch infestations in organic barley seed production