How Choices Made at Planting Impact Barley and Wheat Health

When it comes to crop health, a lot of heavy lifting takes place ahead of planting. Here, we will highlight some of the major decisions that are locked in before your planter hits the ground for wheat and barley.

Seed selection

Seed selection may be the most important consideration when managing grain head diseases, such as Fusarium head blight (FHB, also known as scab) and the mycotoxins it can produce. Selecting a variety that is moderately resistant to FHB is crucial for preventing infection. Layering the protection of a well-timed fungicide on top of this can provide up to 80% disease reduction, whereas using a fungicide without planting genetic resistance can only reduce scab by about 50%. This is not an either/or approach to disease mitigation when pairing resistant varieties with fungicide applications—it is a matter of using both to achieve high-quality grain.

Another area where plant genetics can help reduce FHB is related to plant architecture. Cultivars that have naturally nodding (also considered as wheat spike attitude or spike angle) head types shed water more easily than upright heads. When rain and dew fall off the head instead of collecting in the awns and glumes, the vulnerable areas of the head dry more quickly, making it more difficult for fungi to survive and invade.

Some growers may consider saving grain from a previous crop to use as seed for the following season. While this approach can save costs in the short term, it also increases the risk of exacerbating certain disease problems over time. Certain fungal pathogens, such as those that cause smuts and bunts, may remain on the seed coat, and some viral pathogens can also persist in the seed. If you choose to use stored seed, avoid seed lots that have not been thoroughly cleaned and those from fields with a history of glume blotch or scab. Low test weights, discoloration, and poor germination rates are also causes for concern. Consider fungicidal treatments for your seed, especially if you are planting seed from a lot that you have noticed has smut. These treatments are effective against pathogens that can be carried over on or in seeds, such as bunts and smuts, glume blotch, and scab. Treatments are also effective in reducing stand and yield loss from seed rots and early-season diseases, such as those caused by Fusarium, Pythium, and Rhizoctonia. These diseases can be particularly important if planting is delayed and the seedbed is cool and wet. Fungicidal treatments will not provide control of bacterial diseases or viruses. Seed treatment will also not protect your wheat and barley from the head scab that occurs in the spring; it only provides protection from seedling disease that may occur at germination as a result of planting some scabby seed. Finally, seed treatment will not completely rescue you from bin-run seed quality issues, although it may provide some assistance.  For more information, read about considerations for planting saved wheat seed.

Residue Management

It might not be immediately apparent, but the state of previous crop residue we plant in the fall can have implications for disease management in the spring. Planting no-till into heavy or unevenly distributed residue can prevent seed from emerging at a uniform timing. These plants will then be at slightly different growth stages as they move through the season, resulting in the heads emerging and then flowering at different times. While this could benefit the crop if some of those heads miss a window of unfavorable weather, it will also make it more difficult to time a fungicide spray to protect the maximum number of heads from FHB during flowering. Similarly, we find this effect in wide-row wheat (15' or wider), as planting wide rows promotes more tillering than typical drill spacing. Tillers flower at less predictable times than main stems, so this can result in tough decision-making situations for those wishing to spray a fungicide that covers the window of greatest vulnerability for the crop.

Planting and Fertility Timing

Some major timing decisions can be made now to increase success for the rest of the cropping season. For instance, when we wait to plant our small grains until after the Hessian fly-free date, we also reap the added benefit of reducing the time our plants are exposed to active populations of the aphids that spread Barley Yellow Dwarf Virus. Planting later also reduces the opportunity for other insect vectors to transfer pathogens from volunteer grains to your fresh crop. Since this narrows your window of planting, you might consider planting several varieties with slightly different maturities to spread the risk of the entire crop being affected by unfavorable weather conditions come spring.

Finally, when planning your fertilizer applications, be sure to avoid situations where you will need to apply high levels of nitrogen at greenup. Instead, consider splitting nitrogen applications and ensuring your crop receives adequate potassium and phosphorus. This balanced nutrient strategy supports the development of natural plant defenses, helping protect against early-season diseases such as powdery mildew. Applying excessive nitrogen early in the spring encourages rapid growth of succulent tissue, which is more vulnerable to fungal infections.

What you can do now to grow your healthiest crop next year:

• Choose varieties with FHB resistance
• Grow varieties with nodding heads (spike angle)
• Buy new seed each year instead of saving from a previous crop
• If you no-till, be sure residue is evenly distributed
• Do not plant before the hessian fly-free date
• Plant both early and late varieties
• Plan fertilizer applications so that your crop does not receive high amounts of nitrogen at once

This work is supported in part by USDA-ARS/USWBSI Agreements #: 59-0206-2-099, 59-026-9-122, 59-0206-2-128, 59-0206-0-140, and 59-0206-8-210.