Temporal dynamics of root and foliar severity of soybean sudden death syndrome at different inoculum densities

Abstract

Temporal dynamics of soybean sudden death syndrome (SDS) root and foliar disease severity were studied in growth chamber experiments on susceptible plants exposed to different inoculum densities (0, 100, 101, 102, and 103 conidia g−1 soil) of Fusarium virguliforme. The monomolecular model provided the best fit to describe the progress of root and foliar disease severity over time. Disease severity and area under disease progress curve (AUDPC) both increased in response to increasing inoculum density (P 0.9, P < 0.01) with foliar disease severity assessments performed 30 to 50 DAI. Root biomass was reduced by up to 67% at the three highest inoculum densities, indicating the aggressiveness that F. virguliforme possesses as a root rot pathogen on soybeans.