Controlling rust in oats

submitted by Sara Berges, Allamakee SWCD

Meeting the test weight requirements of food mills is the biggest hurdle for oat farmers when selling food grade oats. In order to increase the test weights, farmers often see a positive yield response from a fungicide application. However, it’s important to understand when to spray the oats to have the most effect on rust.

According to an article by Bruce Roskens from Grain Millers “…fungicides on oats are most effective and should be applied at the first indication of pustules showing on the middle leaves anytime from 2-leaf to heading…”. It is important to start scouting at the 2-leaf stage and continue weekly. Combination fungicides have been found to be more effective than single ingredient products.

Many farmers spray too early, without any indication of rust, while others apply too late to have any effect on fungi. Studies have shown minimal benefit to spraying the crop after heading. The kernel fill has already been impeded and the fungicide may delay maturity. Also, late spraying may increase risk for residue concerns for milling quality oats. It is important to remember to scout in a timely manner and apply fungicide at the proper time, before heading of the crop.