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Clean wheat = higher-yielding wheat
Just shy of 13% of the Kansas wheat crop was lost to disease in 2012, just ahead of the normal pace. That number was higher on account of some diseases like nematodes that are growing in prevalence, adding to losses from more common diseases like striped rust and common bunt that continue to cause economic damage.
That makes it important to do what you can to prevent them from causing more damage in the 2013 crop, and the best way to do that, experts says, is stick to your crop rotation guns, use certified seed and apply seed treatments and fungicides to make conditions as inhospitable as you can for those diseases that will likely be present again in 2013.
"Soil- and seedborne pathogens can survive adverse environmental conditions such as drought and winter temperatures by becoming dormant or forming survival structures. Seedborne pathogens are protected by the seed and/or the environment in which the seed is stored," says University of Nebraska Extension plant pathologist Stephen Wegulo. "When favorable environmental conditions (moisture and ambient temperatures) return, the pathogens become active again. The drought of 2012 will not reduce the risk posed by soil- and seedborne pathogens. Management measures against these pathogens should be taken as they would in a normal year."
With specific diseases, Kansas State University Extension wheat disease specialist Erick DeWolf says it's important not to just focus on the most common ones; don't lose sight of those that could have longer-term implications.
"A lot of future disease management is going to come down to managing the most important ones, and there's certainly been a repeated pattern of stripe rust emerging," he says. "Also, we don't want to lose sight of other diseases because of their long-term ramifications. Diseases like barley yellow dwarf, leaf rust and wheat streak mosaic can all do a lot of damage if we don't manage for them."
Each of those 3 diseases accounted for around 2% of the total disease losses in 2012, but will likely be in play again in 2013, DeWolf says.
Wegulo recommends a 4-pronged approach when looking to keep your seed free of soil- and seedborne disease:
- Use seed treatments
- Plant cleaned seed
- Select disease-resistant varieties
- Continue crop rotations.
"Seed treatments control seed-transmitted pathogens that may be surface-borne on the seed or internally seedborne. In addition, they control soilborne pathogens such as Bipolaris, Fusarium, Pythium, and Rhizoctonia that cause root and crown rots and seedling damping off and blights. Systemic seed treatments also provide additional protection against fall foliar diseases," Wegulo says. "In addition to controlling diseases, fungicide-insecticide combination seed treatments control insect pests such as wireworms, Hessian fly, and fall season aphids. By controlling seedling damping off, seed treatments improve stand establishment and result in healthy, vigorous seedlings."
Add to that a foliar fungicide, DeWolf says. Though some of today's wheat varieties have vastly improved natural resistance to fungal diseases, he recommends adding a fungicide program to your crop's management, especially if you're going to be using your wheat next year for seed.
"I think as we look at varieties available, certainly it pays to try to use genetic resistance where we can. However, there are often genetic weaknesses even in the best-adapted varieties, and that's where we can use fungicides to cover up some of those weaknesses, particularly with some of these very important diseases," DeWolf says. "Part of where I often encourage growers to use fungicide seed treatments are those who have production practices that lend themselves to saving seed. That seed is of a higher value than general grain production, so it's a high priority to use these seed treatments."
And, whether it's a seed treatment or fungicide, use your area's recent history as a guide as to whether or not you should apply, DeWolf adds.
"In recent year's we've had some hot spots of common bunt in the state where a lot of growers have been frustrated by significant dockages or denials at the elevator," he says. "As far as a preventative measure, [disease protection] is appropriate if it's where they've had the disease before or if they have neighbors who have been affected."