Growers in the western provinces are right on the cusp (if not in) prime fusarium season, and knowing the ins and outs of the fungus can give you a leg-up and allow you to get out ahead of the potential problem. There are several factors to consider when dealing with fusarium, including history of the fields, current and future weather conditions, and also plant staging.
Kelly Turkington, plant pathologist with the Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, says first and foremost, to better understand the risk and potential of fusarium of the cereal crop, growers should be aware of any history of the fungus on the field in question, or even neighbouring fields, as this can be an indicator of residue, increasing fusarium potential.
Turkington says when the crop is moving from flag leaf emergence to head emergence is when producers are going to want to start paying attention to the current and upcoming weather by referencing weather-based risk maps. Moisture, temperature and humidity all play a factor in the onset and development of fusarium and should all be taken into consideration when determining when to spray fungicide.
“You have to take it with a grain of salt, to look at what the forecast is like over the next two weeks. You might have conditions that are not overly conducive as the crop is moving from flag leaf into head emergence and think, well, there’s a limited risk here. But if your forecast weather conditions over the next two weeks, suggest a lot more moisture, and from previous experience that you’ve had issues in the field, that’s the situation where things get a bit tricky in terms of trying to make that decision to spray or not to spray,” says Turkington. “But, if the risk is [moderate to] high from flag leaf emergence through the head emergence, that’s a scenario where absolutely you want to get into that crop after head emergence, because you want to protect that head tissue with that fungicide”.
In addition to moisture, temperature and humidity also play a role and Turkington says there are some guidelines that can help growers better determine their risk and when to spray. He says when the temperature is fairly consistently between 10 and 30 degrees Celsius and when humidity is 90 per cent or above, is when fusarium can run rampant.
Although post head emergence tends to be a key time to scout for and spray for fusarium, the fungus can show up later in the growing season as well and if the weather tends to be cooler than the idealistic 10 to 30 degrees C, doesn’t mean your crop is out of the woods. Cooler conditions can mean a delay of the onset of fusarium, which then may see it show up in the cereal crop in the mid to latter part of the green filling period. He says that this may result in a higher concentration of DON, although the grain itself looks fine upon initial review.
To learn more about fusarium and the efficacy of spraying fungicides cereal crops, listen to the full interview between RealAg Radio host, Shaun Haney, and Kelly Turkington, below.