Researcher Studies the Bumps and Bruises of Scabby Seed
August 2, 2017 | View PDF
Gone, but not forgotten, is the blight of the fungal pathogen Fusarium graminearum which happened last year.
In the wake of this rainy-day loving fungus, many questions cropped up which Plant Pathologist Dr. Audrey Kalil is now answering. From the laboratories and test plots at the North Dakota State University Williston Research Extension Center, Kalil has been intentionally planting seed which was infected with F. graminearum.
This type of "scabby" seed is contaminated with a mycotoxin called deoxynivalenol (DON), which is produced by the fungus. Not only do the seeds range from an unappealing "tombstone" white coloration to one which resembles bread mold, the mycotoxin can be harmful in large quantities. "It can make people sick, it can make livestock sick," Kalil said.
When durum is cleaned, they filter out these harmful seeds, but the big question was what to do with the seed once it is contaminated. "That question about planting back the seed, that's what I want to address," Kalil said. "A lot of growers asked me last fall if they could plant it."
This was a reasonable question, but Kalil lacked the appropriate data to give a good answer. Research done in different soil and climates is not always applicable to the situation in the Eastern Montana or Western North Dakota area. "You have to do the research where people are growing their crops," Kalil said. "We really need to have answers that are relevant to the weather conditions, agronomic practices, crops and soil types of this region."
So this year, Kalil hit the field running and planted her test plots with Alkabo durum seed that held varying amounts of the mycotoxin DON. Her results showed that DON in durum seeds is like an overzealous guest. It's fine in small doses, but too much can really kill the party.
Kalil found that the germination rate for seeds which had less than 0.3 ppm (DON is measured in parts per million), was 62%. There was 71% germination at 1 ppm and 66% germination at 3.1 ppm. "It's less than you want, but still usable seed," Kalil said.
The number of plants per square foot for those concentrations were all relatively similar. The real drop off in stands occurred in 10.2 ppm of DON to 19.9 ppm. All plots were planted on April 26th of this year and the stand count was taken in early June.
But from what Kalil has discovered, that's about as good as things could get with the "scabby" seed. "It doesn't matter even if you plant to account for that poor germination, you still have reduced stands out in the field," Kalil said. "That could be a lack of vigor."
Half of each test plot received a fungicide seed treatment, tebuconazole, for control of Fusarium seedling blight. Kalil found that the seed applied fungicide did not improve establishment. Knowing this can save money for farmers dealing with DON contaminated seed.
As for the yield of "scabby" seed, farmers will have to wait a little longer. "I don't have the data yet because the growing season isn't over yet," Dr. Kalil said. "All that data will come out when we release our annual report. So if you want to make any decisions for next season, that information will be available far in advance of the 2018 growing season."
While Kalil is looking forward to sharing her data with local farmers, there is another concern which she is trying to raise awareness for. This warning flag is for something undeterred by the dry conditions this year, and one which has no chemical treatment available.
Wheat Streak Mosaic Virus (WSMV) paid a visit to her "scabby" seed test plots, and she has seen it in other local fields as well. This virus, caused by a tiny but mighty mite, can cause wheat losses of 50% to 100%. "The winter wheat is not your main concern with yield loss because there are relatively resistant varieties available (Jerry, Ledger, Mace), it's your spring planted small grains such as wheat, durum, and barley," Kalil said.
As far as her research on the effect of DON was concerned, her test area with the Alkabo durum didn't take any heavy losses and she was easily able to continue her study. "If it's equal on all plots, I can still get results out of that because you're comparing apples to apples," Kalil said.
Possibly the only positive aspect to WSMV is that no expensive chemical treatments are necessary. To rid a field of the mites, which only feed on live plants, dead area in a field is required for two weeks. Green bridges, or green infected plants in or near a field which can also house the mites, are the source of the virus. Kalil recommends keeping an eye on the types of weeds or grass surrounding a field, and also coordinating with neighbors if WSMV is suspected. "There's nothing you can do about this virus, except using these agricultural practices," Kalil said.
It's also good to keep in mind that these critters don't just crawl. "They can ride the wind," Dr. Kalil said. "They can do it on purpose."
Even while Kalil is closely monitoring the WMSV situation, and patiently awaiting the results for yield from the "scabby" seed, she always has an ear available for questions from farmers. "This whole trial resulted from grower questions that I could not find a good answer for," Kalil said.
Well on her way to finding that answer, Kalil and the scientists at the NDSU Williston Research Center will continue to seek out new information, and new relevant data. "I do plan on repeating this next year," Kalil said. "This was really interesting. It was unexpected. I want to be sure that what I am seeing is what a farmer in our region would experience regardless of what that spring might hold weather-wise."