by Katie Navarra
Small grains crops have reached the middle of the growing season and it’s time to plan fungicide applications. “Head blight is such an important disease to control,” said Aaron Gabriel, Sr. Extension Resource Educator in agronomy for Cornell Cooperative Extension.
If the spores of the Fusarium head blight fungus germinate in the developing grain, the seed becomes shriveled and infected with the fungus. “Affected grains are lighter so the combine can sometimes be adjusted to remove light kernels, but distillers and brewers are particular in the quality they will accept,” he said.
Not only can Fusarium head blight lower crop test weights and yields, it can lead to the development of a mycotoxin called deoxynivalenol (DON), also known as “vomitoxin.” The levels of DON in a load of grain can lead to discounts or rejections at the delivery location.
Acceptable DON levels vary based on intended use. For example, one part per million (ppm) on finished wheat products, such as flour, bran and germ, is the acceptable level on products that potentially may be consumed by humans. Maltster only accepts barley and grains with 1 ppm or less of DON. Distillers will accept grain with 30 ppm of DON. Fungicide applications are the key to maximize the price paid for your small grains and to avoid potential rejection.
During a field workshop held June 16, at Indian Ladder Farms in Altamont, NY, Gabriel discussed the timing of fungicide and nutrient inputs as well as demonstrated handheld devices that can help small grain farmers manage their crops.
When to apply
Fungicides need to be applied once wheat and barley seed heads are exposed and flowering occurs (the point when anthers are shedding pollen). Every field is different in the exact timing of when the grains will flower. It is important to take the time to watch plant development since there is a six-day window to apply fungicides in a timely manner.
Fungus spores are especially sensitive to moisture. The higher the moisture level, the more likely head blight will develop. So far in 2016, it has been relatively dry at the point where grains crops are getting ready to head. When there is a lot of rain at this point in the growing system, the wet conditions can foster fungus. Heavy dews also provide enough moisture for disease development. Sometimes head blight will be present, but the fungus will not produce much DON. Having a mycotoxin analysis is needed to determine quality.
Fortunately, there is a nationwide alert system that can warn farmers when conditions in a particular region of the country are likely to foster Fusarium head blight. The U.S. Wheat and Barley Scab Initiative (USWBSI) website offers real time alerts and access to a searchable tool based on the commentary of wheat disease specialists throughout the country and are part of the disease prediction and outreach efforts sponsored by the Initiative.
To subscribe to the alert system, visit http://scabusa.org/fhb_alert.php .
The tool can be accessed on-line at: www.wheatscab.psu.edu/riskTool.html .
In addition to fungicide application, cultural management practices that include crop rotation and use of clean, certified seed, limit disease development. “Barley should never follow corn or wheat, and wheat should not follow corn or barley,” Gabriel said.
Timing is critical in many aspects of small grains crops. Knowing if and when a crop needs additional Nitrogen to increase protein is important for grains headed to brewers and distillers. “Maltsters look for 9 to 12.5 percent protein in small grains,” Gabriel said.
Determining application rates and the timing of Nitrogen application is easier with the help of handheld devices like a Greenseeker. This device can measure how green the crop is, which helps farmers manage crop inputs. Gabriel and other cooperative extension agents in the region have a device called a Greenseeker. “You use the device above the crop canopy to take a reading of how green the crop is. Then you use that alongside a reference guide to determine nutrient inputs,” he said.
The tool is especially helpful for corn and small grains, but can be used with any crop. Farmers in the Capital Region interested in seeing the tool at work can contact Aaron Gabriel at firstname.lastname@example.org or by phone at 518-380-1496.
At harvest, timing is important because of the moisture content in the grains. “With wheat, oats and rye you want to let them dry down to 13 percent moisture before harvest so they’ll be ready for storage,” he said.
Barley can be tricky. If grain is left on the plant too long and it rains, the seeds can sprout. The key is to harvest barley before it completely dries in the field to remove it from a dangerous environment. “Barley is typically harvested at 16 to18 percent moisture and then warm air (less than 100 degrees Fahrenheit) to dry it down for storage,” Gabriel said.
Determining the readiness of the crop for harvest can be done through visual observation. “Once the stem below the seed head turns brown or dry, the grain is physiologically mature,” he explained, “that’s when you should start watching the moisture content and get prepared to harvest.”
Gabriel also recommends the use of a handheld grain harvester to test smaller areas of the field, approximately one square yard. The grains harvested in that area can be put in a moisture meter and/or sent off to the lab for analysis.
June 2016 was relatively dry. That is problematic for some crops, but that may be good for small grains growers. “I think we’re doing pretty well from what I am seeing and hearing,” Gabriel said.
As of mid-June some fields were still within the window of opportunity for fungicide applications. “The next thing we’ll need to be thinking about is rain,” he said, “if it rains pre-harvest, sprouting could be a big issue.”