Effect of Crop Rotation and Management On Fusarium Spp. Diversity.

Fusarium spp. represents a large complex of pathogens that colonize and infect field crops.  Crop rotation, genetic resistance, and fungicides are the primary methods used for managing this complex. To date there is a paucity of information on the interactions of these management strategies and how they impact Fusarium spp. population dynamics.  Therefore the objectives of this experiment were to quantify the effect of crop rotation and management on Fusarium spp. (F. graminearum, F. verticillioides, F. virguliforme, and F. oxysporum) diversity and population dynamics.  Soil was collected in 2011 and 2012 from a long term corn-soybean-wheat rotation experiment located near Arlington, WI. The plots are configured in a randomized complete block split-plot design with 3 replications where the main plots consist of 14 crop rotation sequences. The sub-plots consist of rotational sequence of susceptible and resistant cultivars (RR, SS, RS, and SR) and fungicide treatments (UTC, treated).  Previously developed primers for the qPCR were selected based on their specificity for each Fusarium spp.  A qPCR assay and standard curve was optimized for each species using pure culture DNA.  The population for each species (spores g^-1 soil) was quantified from extracted soil DNA. Preliminary results suggest that F. oxysporum was the most prevalent Fusarium spp. found.