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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #415497
Research Project: Enhancing Agronomic Performance and Nutritional Qualities of Pulse Crops

Location: Grain Legume Genetics Physiology Research

Title: Evaluation of fungicide seed treatmnents for control of chickpea damping-off caused by metalaxyl-resistant Pythium spp. 2023

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

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2024
Publication Date: 8/26/2024
Citation: Chen, W., McGee, R.J., Vandemark, G.J. 2024. Evaluation of fungicide seed treatmnents for control of chickpea damping-off caused by metalaxyl-resistant Pythium spp. 2023. Plant Disease Management Reports. 18:ST008.

Interpretive Summary: Chickpeas, especiaally large-seeded chickpeas, are very vulnerable to seed rot and pre-emergence damping-off caused by Pythium spp. This disease has been traditionally managed using seed treatment with the fungicide metalaxyl. However, development of metalaxyl-resistant Pythium populations has caused disease 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 2023, we evaluated the fungicide GWN-9790 in a field trial using three application rates. Results demonstrated that GWN-9790 and several other experimental fungicides were effective against metalaxyl-resistant Pythium. These new seed treatment options can be used as alternatives for managing metalaxyl-resistant Pythium.

Technical Abstract: The chickpea disease Pythium seed rot and damping-off has been traditionally managed using seed treatment with the fungicide metalaxyl. However, populations of metalaxyl-resistant Pythium spp. 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 to rotate with ethaboxam. A field trial was carried out in 2023 to identify additional seed treatment fungicides for controlling metalaxyl-resistant Pythium. High levels of disease pressure were present due to natural inoculum and irrigation immediately after planting, and severe seed rot and pre-emergence damping-off occurred during the trial. Essentially no seeds emerged in the check treatment plots due to the presence of metalaxyl-resistant Pythium. The fungicide GWN-9790, as well as several other chemicals, significantly improved chickpea germination at different application rates. In summary, the fungicide GWN-9790, was effective against metalaxyl-resistant Pythium, providing effective fungicides for rotational applications.