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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #404490
Research Project: Improving Genetic Resources and Disease Management for Cool Season Food Legumes

Location: Grain Legume Genetics Physiology Research

Title: Evaluation of fungicide seed treatmnents for control of chickpea damping-off caused by metalaxyl-resistant Pythium spp. in 2022

Author
item Chen, Weidong
item McGee, Rebecca
item Vandemark, George

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2023
Publication Date: 8/30/2023
Citation: Chen, W., Mcgee, R.J., Vandemark, G.J. 2023. Evaluation of fungicide seed treatmnents for control of chickpea damping-off caused by metalaxyl-resistant Pythium spp. in 2022. Plant Disease Management Reports. 17:ST010.

Interpretive Summary: Large-seeded chickpeas are very vulnerable to seed rot and pre-emergence damping-off caused by Pythium spp. This disease has been traditionally managed successfully using seed treatment with fungicide metalaxyl. However, development of metalaxyl-resistant pythium populations has caused metalaxyl control failures in the inland Pacific Northwest. It was previously found that seed treatment with ethabaxom alone or in combination with metalaxyl was effective at protecting chickpea from seed rot and damping-off caused by metalaxyl-resistant Pythium. In 2022, we evaluated the fungicide GWN-9790 at three application rates. The field trial in 2022 showed that GWN-9790, as well as ethaboxam, was effective against metalaxyl-resistant Pythium. This new seed treatment option could be used as an alternative in managing metalaxyl-resistant Pythium.

Technical Abstract: The chickpea disease Pythium seed rot and damping-off has been traditionally managed using seed treatment with fungicide metalaxyl. However, populations of metalaxyl-resistant Pythium spp. have emerged several years ago and rendered metalaxyl ineffective. Recent studies showed that ethaboxam was effective in protecting chickpea seeds from seed rot and damping-off caused by metalaxyl-resistant Pythium. Additional effective fungicides are needed for rotation with ethaboxam. A field trial was carried out in 2022 to identify additional seed treatment fungicide for controlling metalaxyl-resistant Pythium. High levels of disease pressure were present due to natural inoculum and heavy rain immediately after planting, and severe seed rot and pre-emergence damping-off occurred during the trial. Essentially no seeds emerged in the check treatment and metalaxyl-treated plots due to the presence of metalaxyl-resistant Pythium. The fungicide GWN-9790 significantly improved chickpea germination at the three tested application rates and was as effective as ethaboxam. In summary, the fungicide GWN-9790 as well as ethaboxam, was effective against metalaxyl-resistant Pythium, providing effective fungicides for rotational applications.