Small Grains Disease Update 06/28/2019
Both the crops in the trials and in fields I visited look very good. The earliest barley, oat, and spring wheat fields have started to head across not just the south but even northwest Minnesota. These fields will quickly approach anthesis if they did not already with the rapid increase in daytime highs over the past few days.
Overall very little if any disease or insect problems could be found in the trials. The only exception being leaf rust in the lower canopy on susceptible rye varieties in the rye variety trials, a few stripe rust pustules on Prosper HRSW, and the start of net blotch on Pinnacle barley.
The scouts continue to find tan spot and aphids south of the US Hwy 2. Aphids counts are increasing and approaching threshold in a few instances.
The risk assessment models for all three leaf diseases had been trending higher this past week across most of the State. The expected daytime highs over the weekend and early next week will likely mean that the infection risk for tan spot will trend much lower while the risk for leaf rust, and Septoria infections will decline as well.
In contrast, the infection risk for FHB will likely continue to increase. Most of the state has, depending on the level of genetic resistance of the variety, had seen moderate to high risk for FHB in the past couple of days. Keep an eye on the risk models and seriously consider a fungicide treatment at Feekes 10.51 or beginning of anthesis.
--Jochum Wiersma, Extension Agronomist, University of Minnesota Crookston
For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu
For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org