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POSTERS: Biological control

Rhizophagus intraradices Reduces Disease Severity of Sudden Death Syndrome on Soybean
Michelle Pawlowski - Univ of Illinois Urbana Champaign. Glen Hartman- USDA-ARS At the University of Illinois

There is increasing interest to incorporate arbuscular mycorrhizal fungi (AMF) into agricultural production because of the benefits they provide, including protection against pathogens and pests. Sudden death syndrome (SDS) of soybean is a devastating disease caused by the soil-borne pathogen Fusarium virguliforme. Multiple management methods are needed to control SDS. There is little known about the relationship between F. virguliforme and AMF. The overall goal of this study was to determine if the AMF species Rhizophagus intraradices could reduce SDS severity of soybean. Fourteen soybean genotypes were evaluated for their response to F. virguliforme and with or without R. intraradices in a greenhouse experiment. On average, there was a 45% reduction in foliar SDS severity and a 27% reduction in relative F. virguliforme quantities in roots across all genotypes in mycorrhizal plants compared to non-mycorrhizal plants. Root weight of mycorrhizal-inoculated plants was significantly increased by 56% compared to non-mycorrhizal plants. A nutrient analysis of root tissues showed a 75% increase in mycorrhizal roots of potassium and increases in phosphorus, sulfur, boron, and aluminum compared to non-mycorrhizal roots. This study showed that R. intraradices considerably reduced SDS severity and F. virguliforme colonization while simultaneously increasing growth and nutrient uptake of plants. This potential of R. intraradices and possibly other AMF species may be an effective strategy for use in a multi-management approach to control SDS.