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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #327326
Title: Field evaluation of seed treatment fungicides for control of damping-off of chickpea caused by metalaxyl-resistant Pythium spp, 2015

Author
item Chen, Weidong
item GUY, STEPGEN - Washington State University
item McGee, Rebecca
item Paulitz, Timothy
item Porter, Lyndon
item Vandemark, George
item SCHROEDER, KURT - University Of Idaho

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2016
Publication Date: 9/5/2016
Citation: Chen, W., Guy, S., McGee, R.J., Paulitz, T.C., Porter, L., Vandemark, G.J., Schroeder, K.L. 2016. Field evaluation of seed treatment fungicides for control of damping-off of chickpea caused by metalaxyl-resistant Pythium spp, 2015. Plant Disease Management Reports. 10:ST017.

Interpretive Summary: Pythium spp. are ubiquitous and often cause seed rot and damping-off in cool and wet conditions. However, Pythium seed rot and damping-off have been effectively managed through seed treatment with the fungicde metalaxyl. Through continual use of metalaxyl over the past three decades, many Oomycete pathogens including Pythium spp. have developed resistance to metalaxyl. Pythium populations with metalaxyl resistance have become a problem for chickpea production in the US Pacific Northwest. Chickpea seeds, particularly large kabuli-seed types, are especially vunerable to Pythium damping off. Recently, traditional seed treatment with metalaxyl has become ineffective at protecting chickpea from seed rot and damping-off caused by metalaxy-resistant Pythium. In 2014, large areas of chickpea seeds treated with metalaxyl failed to germinate in several fields and metalaxyl-resistant Pythium spp. were isolated from nongerminated seeds and soils around nongerminated seeds. In 2015, we evaluated an alternative fungicde ethaboxam for managing metalaxyl-resistant Pythium in three fields. Results of stand counts showed that ethaboxam can protect chickpea seeds from Pythium seed rot and damping-off in field where metalaxyl had failed, suggesting that ethaboxam is an effective option for managing metalaxyl-resistant Pythium spp.

Technical Abstract: Pythium spp. are ubiquitous and often cause seed rot and damping-off in cool and wet conditions. However, Pythium seed rot and damping-off have been effectively managed through seed treatment with the fungicde metalaxyl. Through continual use of metalaxyl over the past three decades, many Oomycete pathogens including Pythium spp. have developed resistance to metalaxyl. Pythium populations with metalaxyl resistance have become a problem for chickpea production in the US Pacific Northwest. Chickpea seeds, particularly large kabuli-seed types, are especially vunerable to Pythium damping off. Recently, traditional seed treatment with metalaxyl has become ineffective at protecting chickpea from seed rot and damping-off caused by metalaxy-resistant Pythium. In 2014, large areas of chickpea seeds treated with metalaxyl failed to germinate in several fields and metalaxyl-resistant Pythium spp. were isolated from nongerminated seeds and soils around nongerminated seeds. In 2015, field plots were established to evaluate three fungicides alone or in combination at various concentrations as seed treatments to protect chickpea from Pythium seed rot and damping-off in three fields. A randomized complete block design with four replications was implemented at each site. Results of stand counts showed that in fields where metalaxyl-resistance is not a problem, either metalaxyl or ethaboxam can successfully protect chickpea seeds from seed rot and damping-off. However, in field where metalaxyl-resistant Pythium is a problem, only treatment with ethaboxam can protect chickpea seeds, suggesting that ethaboxam is an effective option for managing metalaxyl-resistant Pythium spp.