This is a seeding season where pre-planting testing of wheat seed is an important first step, and seed treatments may be more important than ever.
With unprecedented levels of fusarium head blight infection in Manitoba wheat in 2016, farmers should get their wheat seed tested for germination, consider testing for the presence of pathogens and vigour and also consider a seed treatment.
“If you are concerned about your seed quality get it tested and don’t be surprised if this is a year you need to treat when you normally don’t,” Manitoba Agriculture plant pathologist Holly Derksen said in an interview last week.
“Using a seed treatment I think is going to be a big part of our cereal crops in 2017,” she said during the CropTalk Westman webinar April 19.
Even seed without visible fusarium damage can still be infected with fusarium, Derksen said.
The odd wheat field may have missed being infected by flowering later in the season, she said.
“But if they had fusarium they should seriously consider a seed treatment especially if you’re going into not great conditions,” Derksen said. “If you are going to wait until it’s warm and dry (to seed) and the crop is going to be out of the ground in three days then maybe (they can skip seed treatment) and even with a high infection the germination might still be OK.”
In total 96 per cent of the Manitoba 2016 wheat seed that’s been tested at 20/20 Seed Labs is infected with with fusarium graminearum, said Sheri Lafreniere of 20/20 Seed Labs during the webinar. And on average 25 per cent of the wheat kernels had some level of the disease, ranging from almost nothing to as high as 53 per cent. Normally two to five per cent of kernels are infected, she said.
Seed infection rates in 2016 are probably as high as they’ve ever been, Derksen said later.
Seed infected with fusarium and other pathogens is susceptible to many seed and seedling diseases, which can kill the plant before of after emergence, resulting in a reduced plant population and/or plants at different growth stages, Derksen said. Both can result in lower yields and the latter complicates weed and disease control. Wheat is susceptible to fusarium infection at anthesis. A fungicide applied at early flowering can help protect the crop, but it won’t be as effective if the crop is at multiple growth stages.
While Alberta Agriculture recommends farmers apply a seed treatment every year, Manitoba Agriculture’s position is to leave the decision to farmers, Derksen said. That’s because research has found seed treatments don’t offer much advantage when seed has less than 10 per cent fusarium infection.
Fusarium isn’t the only pathogen that can hurt seed and seedlings. And some of those pathogens in addition to being seed-borne can also be found in the soil and in crop residue.
“When you know you have it on the seed you definitely know you have the potential for that seed to occur,” Derksen said.
When seed germination is reduced it is important to compensate by upping the seeding rate and trying to plant into ideal conditions and at the proper depth, she said. Seed treatments last for about two weeks after planting.
“You want it (crop) to get through that seeding stage before the seed treatment wears off,” Derksen said. “You don’t want it sitting in the cold ground for seven days before it even emerges obviously, because you have less time to get through… the most susceptible stage. And that really goes for any crop.”