Wheat growers know that Fusarium head blight (FHB), also referred to as scab, can be highly detrimental to profits, cause grain with low test weights, lost yield, low germination and mycotoxin contamination. This causes sterile florets and from florets that do produce grain the kernels can have a shrunken, chalky, white appearance, which has earned them the industry moniker of “tombstones.”
The Fusarium pathogen that causes scab isn’t unique to wheat. In fact, it causes disease in other crops such as corn, and it can overwinter between crops among field stubble. This means that crop rotation practices often used to manage worm and insect pests aren’t effective when it comes to FHB.
“For example,” explained Jason Manz, cereals marketing manager, Bayer CropScience, “If scab is present in a wheat field one year, it can overwinter, showing up in that field the next year as Gibberella stalk rot in corn. Plant wheat the next year, and the cycle continues.”
North Dakota State University and other universities recommend the use of fungicides, among other management practices, to help growers interrupt the FHB life cycle and manage scab in wheat. Growers should recognize that not all fungicides are created equal.
The mycotoxin DON, commonly referred to as vomitoxin, is produced in wheat and barley grain infected by FHB.
Strobilurins: Use Caution
Wheat growers often assume that strobilurin chemistries, which are very effective at controlling foliar disease, will be just as effective against scab. That is not the case, and poorly timed strobilurin application can, in fact, do more harm to your crop than good.
“Growers who use strobilurin chemistries face an even greater risk because the formula does not contain any active ingredients for countering scab,” Randy Myers, Bayer CropScience product development manager, explained. “In fact, strobilurins applied after the flag leaf growth stage may actually initiate increased DON levels.”
Yet an answer is available. To prevent dangerous levels of DON from cropping up and draining grain, many university Extension agents are recommending using Prosaro fungicide along with responsible management practices.
Results from 31 winter wheat trials administered in Indiana and Ohio revealed that when Prosaro was applied at 6.5 fluid ounces per acre during the Feekes growth stage, DON contamination levels decreased from 3.57 parts per million to 1.18 ppm. Another study analysis for 2008-2010 focused on yield potential in winter and spring wheat. For winter wheat, 169 trials gathered in Ohio, Indiana, Kentucky, Missouri, Michigan, Tennessee and Illinois reported an average of 75.9 bu/A on untreated grain, with a jump to 89.3 bu/A on acreage protected by Prosaro. In spring wheat, 28 plots were tested in North Dakota, South Dakota and Minnesota, with Prosaro pulling off 76.7 bu/A over untreated wheat at 70.4 bu/A.
More about identification of FHB in wheat, what DON means to growers and management practices are at www.Prosaro.us.