Window to Treat for Wheat Scab in Carolina Counties Quickly Closing

Late last week, NC State Small Grain specialist Dr. Randy Weisz sent out alerts about weather conditions in certain counties in North Carolina that were highly susceptible to wheat scab:

“It can infect wheat only in a narrow window, right around the time the wheat is flowering, that’s right after the heads come out. And if the weather conditions are just perfect, that means it has to be very warm and very wet at the time the wheat is flowering, then the fungus will infect the head, but you won’t know it for another maybe three weeks or so later, and at that point, it’s too late to treat.”

Weisz explains that the window to use fungicides to prevent head scab is very narrow:

“The infection period is right around flowering, but that’ also is the time when you have to treat, that’s the only time when our fungicides are any good. So, basically you are forced to treat for this disease before you know whether you’re going to get it or not, and you may say well, why doesn’t every body treat and not worry about it. And the reason is because the fungicides are special fungicides, they’re not our normal, standard fungicides that we use…that growers are used to, they’re expensive. And generally speaking at best, you only get about 50% control.”

But, the danger has passed for most of the wheat fields in the state, thanks to the cooler temperatures:

“So what happened last week, toward the middle and the end of last week, was that we had a period of several days, when the temperatures… when the temperatures and the humidity had consistently right in many counties along the coast, and along the southern border of North Carolina, so our North and South Carolina border, in those counties the weather conditions had been right, that we would anticipate that if growers had wheat that was flowering on those days, that we would anticipate that if growers had wheat that was flowering on those days, those fields could likely become infected with head scab, and they should be thinking about spraying.”

And of the wheat fields that were flowering last week, the window of opportunity to treat is quickly closing:

“It’s like within a week of flowering, so it’s not something growers can sit around and debate, that’s why we get these alerts out. And the other thing that the growers can think about is that ‘my wheat is at risk to getting this disease, that’s what the alerts are telling me ‘they can look at their variety; if their variety is fairly resistant to this disease, they probably can get away without spraying, but if it’s a susceptible variety, they really need to spray, today, tomorrow, you know, pretty quick.”

For more on the threat of wheat scab, visit our website sfntoday dot com.

or check out this website that monitors conditions all across the country for wheat scab conditions is dedicated to serving the agricultural industry in the Carolinas and Virginia with the latest ag news, exclusive regional weather station readings, and key crop market information. The website is a companion of the Southern Farm Network, provider of daily agricultural radio programming to the Carolinas since 1974. presents radio programs, interviews and news relevant to crop and livestock production and research throughout the mid-Atlantic agricultural community.