Research Report: Reducing Fusarium Head Blight Vomitoxin Levels through Agronomic Practices

By Katherine McLachlan Rod, Carrie Knott, and Carl Bradley

Every year, vomitoxin levels caused by Fusarium graminearum, in soft red winter wheat are of major concern to wheat producers and millers. Current agronomic practices to reduce vomitoxin levels include planting moderately resistant wheat cultivars and fungicide applications at Feekes 10.5.1. The Kentucky Small Grains Growers’ Association funded a  research trial examining additional agronomic practices that have the potential to lower  vomitoxin levels; harvesting wheat at higher grain moisture (20-22%) and infurrow phosphorus applications at planting.

The objectives of this study are to 1) investigate the effect of harvesting wheat at different grain moisture contents on vomitoxin levels and grain yield, and 2) investigate the effect of phosphorus applications at planting on flowering date, vomitoxin levels, and grain yield.

Experimental fields were established in the fall of 2016 at the University of Kentucky’s Research and Education Center in Princeton, KY. There was one field of ambient infection of F. graminearium and one field that was inoculated with F. graminearium infested scabby corn and irrigated to promote Fusarium Head Blight (FHB) development and infection in the spring. Each of these fields had a normal (mid-October) and late (mid-November) planting date and an early (20-22% grain moisture) and normal (13-15% grain moisture) harvest timing. Within each of the planting and harvest timings there was four treatments consisting of two cultivars (FHB susceptible Cumberland and FHB moderately resistant Pembroke 2016) and two in-furrow phosphorus applications (0 lbs/A of P2O5 and 42 lbs/A of P2O5). Trials were harvested in June 2017. The early harvest of the October planting occurred on June 8th, while the early harvest of the November planting occurred on June 12th. The normal harvest of both plantings was on June 21st. Wheat harvested at 20-22% grain moisture were placed into drying columns owned by UK’s Biosystems and Agricultural Engineering, where the grain was dried to 12.5% moisture. Grain samples were sent to a commercial laboratory for vomitoxin analyses.

This was the first year of a three year study. Based on preliminary analysis of the data, our results are inconclusive. One field had significantly higher yields for the high grain moisture harvest timing compared to the normal harvest timing. We also found that the in-furrow phosphorus treatment had no effect on flowering date. It is unclear what, if any, effect the 2016 freeze event had on this study, therefore additional data is needed before conclusive findings can be made. This project has been funded for a second year. In 2018 we plan to determine the effect of in-furrow phosphorus on flowering uniformity, as well as having an additional treatment of an increased seeding rate of 56 seeds ft2 to focus on uniformity of flowering and capturing all of the developing heads at Feekes 10.5.1, when fungicides are applied.