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Integrated Fusarium head blight management under irrigation in spring wheat in Idaho

Juliet Marshall: University of Idaho

<div>Fusarium head blight (FHB) is an emerging disease in Idaho due to increased acreage of corn for dairies. A fungicide trial was conducted in southern Idaho for two consecutive years to evaluate the integrated management strategies for reducing FHB and deoxynivalenol (DON) in spring wheat. Four varieties (Klasic, Diva, IDO1202S and IDO851) were planted in a split-plot arrangement with 4 replications, with timing of fungicide application as the main plot and variety as sub-plot. Fungicides were applied at anthesis only (Prosaro) and anthesis + 4 days (Prosaro + Caramba, Caramba + Folicur and Proline + Folicur) using a CO<sub>2</sub> backpack sprayer at a rate of 20 gal/A. Within 24 to 36 hours of the anthesis fungicide application, a conidial suspension (100,000 macroconidia/liter) was applied on all plots with a CO<sub>2</sub> sprayer with three Teejet 8003 VS nozzles at a ground speed of 1 second per foot at 40 psi. Using the GLIMMIX procedure (SAS 9.4), the variety by fungicide treatment interactions were determined for FHB index, FDK, test weight and yield. Fungicide treatments, especially Prosaro + Caramba, significantly reduced FHB Index, FDK and DON of susceptible (Klasic) and moderately susceptible (IDO1202S and Diva) varieties. The benefit of using the additional post-anthesis fungicide application was only observed in Klasic. Resistance is still the most effective strategy to prevent disease and yield loss as shown by the moderately resistant variety, IDO851. Validation of susceptibility and resistance in the next generation of wheat varieties combined with anthesis fungicide applications will determine economic and strategic benefit of IPM methods.</div>