By JEFF BURBINK
Extension Educator, Purdue Extension Elkhart County

Jeff Burbrink

GOSHEN— Driving through the county, you might see some white heads of wheat standing out against a sea of green. In other cases, you might see a patch of these white heads standing together in a pocket of a field. What causes this? 

There are several common causes for wheat to turn white in a field. In our area, one of the more common issues is a disease called head scab. Head scab also known as fusarium head blight. Fusarium is a wet weather disease, so when you see it on the wheat head, you know it was raining when the plant was pollenating.

Wheat heads pollinate over a three or four day period of time. When pollination occurs, it starts in the middle of the head, and works its way up and down the head. If it rains on the first day of pollination, but does not on the second or third day, you might see a white band of color form in the middle of the wheat head, with the lower and upper portions of the head remaining a green, healthy color. That’s a sign telling you the rains fell on the first day of pollination, but not the last. 

Likewise, if you see a green band around the middle of the head, but white bands above and below, you know it rained later in the pollination process.

Unfortunately, wheat that has severe head scab is often accompanied by lower grain yield, and lower quality. It has not been unusual to see crop losses in the 25% range when head scab strikes. Even worse, the fusarium organism can create a byproduct known as vomitoxin, and like the name implies, it can make the grain unusable for a feed. In fact, most grain elevators routinely test wheat for vomitoxin and severely discount the price of wheat if vomitoxin is found. 

Other causes of white wheat heads can include hail damage, freeze injury, several different root and foliar diseases. When diagnosing wheat issues, it is always good to look at the whole field, to see if the problem is localized or spread throughout the area.