Wheat and Barley Disease Update

Alyssa Koehler, Extension Field Crops Pathologist; akoehler@udel.edu

The cooler weather has kept small grains from moving quite as fast as we expected a few weeks ago. Barley varieties are continuing to head out and most wheat is at Feekes 9-10. These cooler temperatures have kept powdery mildew visible in many fields. Powdery mildew appears as white, fluffy growth on the leaf surface (Figure 1). Powdery Mildew grows best at temperatures 50-70°F and typically declines after temperatures are above 75°F. Powdery Mildew that stays low in the canopy has little effect on yield.

White fluffy growth on powdery mildew on wheat leaves

Figure 1. White fluffy growth on powdery mildew on wheat leaves

Over this week, we have remained at a low predicted risk for Fusarium Head Blight. If making a fungicide application this season, the North Central Regional Committee on Management of Small Grain Diseases has put together a list of products and efficacy ratings for the most common small grain diseases. This publication can be found at: https://crop-protection-network.s3.amazonaws.com/publications/fungicide-efficacy-for-control-of-wheat-diseases-filename-2019-07-01-160518.pdf  . Table 1 shows a summary of the results.

Table 1: Fungicide Efficacy for Control of Wheat Diseases (CPN-3002W)