Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2016
Publication Date: 9/5/2016
Citation: Chen, W., Vandemark, G.J., McGee, R.J. 2016. Field evaluation of fungicides for control of Ascochyta blight of chickpea, 2015. Plant Disease Management Reports. 10:FC196.
Interpretive Summary: Ascochyta blight of chickpea caused by the fungal pathogen Ascochyta rabiei is one of the most important foliar diseases of chickpea in the United State and elsewhere. Management of the disease is through using moderately resistant cultivars and application of fungicides. Although effective fungicide are available for controlling Ascochyta blight, the pathogen is known to develop resistance to certain fungicides and alternative fungicides should be evaluated and made available to improve management efficacy and to prevent development of fungicide resistance in the pathogen population. To evaluate foliar fungicides against Ascochyta blight of chickpea, a field trial was established near Pullman, WA. By comparing new fungicides with previously effective fungicides, it was found that the fungicides Elatus and a new experimental compound A20259 were as effective or more effective than previously available fungicides in managing chickpea Ascochyta blight. These new fungicides could be used in fungicide rotations in controlling chickpea Ascochyta blight and preventing development of fungicide resistance.
Technical Abstract: Ascochyta blight of chickpea caused by the fungal pathogen Ascochyta rabiei is one of the most important foliar diseases of chickpea in the United State and elsewhere. Management of the disease is through using moderately resistant cultivars and application of fungicides. In order to evaluate foliar fungicides against Ascochyta blight of chickpea, a field trial was established near Pullman, WA. The fungicide trial was planted using a randomized complete block design with four replications. The plots were inoculated with a mixture of conidia from eight isolates - four of pathotype I and four of pathotype II. An appropriate amount of the conidial suspension was added to water in the tank of a backpack sprayer dedicated specifically for Ascochyta inoculum to give a final concentration of 2 x 105 spores per ml, Disease severity of each whole plot was evaluated based on a 1-to-9 scale. Results showed that all fungicides except Vertisan significantly reduced disease severity over the water control, with the most significant effects resulting from applications of A20259, Headline, Elatus, Priaxor and Propulse. In summary, almost all fungicide treatments tested were effective to a certain degree against Ascochyta blight, and are available for fungicide rotations to prevent development of fungicide resistance.