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Picking Spray Times Could Get Easier

“You can get a comfort level as you keep

changing the scenarios.”


Anew tool to help farmers pick the best time to spray crops with pesticides could be available in Manitoba this spring.

SprayCast is a web-based program that forecasts the optimum spray time within a three-day window designed by Weather INnovations Incorporated (WIN) of Chatham, Ont.

Manitoba Agriculture, Food and Rural Initiatives (MAFRI) will decide soon on whether to co-operate with WIN and offer the program here, Andy Nadler, MAFRI’s agricultural meteorologist said in an interview last week.

“There’s not much to start up so it’s pretty straightforward to go,” he said, adding that it likely will happen.

Several Manitoba farm groups have expressed interest in the program, which gives farmers, based on their field location, hourly expected wind speeds and direction and rates their suitability for spraying, Ian Nichols, WIN’s business manager, told Winter Cereals Manitoba’s annual meeting here March 10.


Winter Cereals Manitoba is one of the farm groups interested in helping sponsor the program.

In Ontario, SprayCast ( sponsored by the Ontario Wheat Producers Marketing Board and Bayer CropScience.

“I have some indication from Bayer CropScience that they would encourage the adoption of it here (in Manitoba), but again we haven’t talked specifics,” Nichols said.

DONCast is another web-based program offered by WIN that might come to Manitoba in future years, Nadler said. Winter wheat growers have already expressed interest in it, he said. A pilot project would be the first step to see if the model works here or needs tweaking, Nadler said.

DONCast predicts the level of DON (deoxynivalenol) in wheat at harvest. DON is the toxin sometimes produced by fusarium head blight (FHB). With a forecast, farmers can decide whether it’s worthwhile applying a fungicide or not.



says SprayCast will likely be available in Manitoba this spring, with a final decision coming soon.


Weather is a key factor in the development of fusarium and DON. The risk of infection increases if it’s warm and moist when wheat is flowering. Other factors include the source of inoculum and the susceptibility of the variety being grown.

To use DONCast, farmers plug into the program their field locations and the day they expect their wheat to flower, which is defined as when three-quarters of wheat heads have fully emerged from the sheath, Nichols said.

Early in the season that date will just be a guess so farmers need to revise the date as it gets closer. The program matches the weather forecast for that field with the flowering time and considers other factors such as crop rotation and variety and then predicts the level of DON. If farmers don’t trust the weather forecast they can enter their own weather possibilities.

“You can get a comfort level as you keep changing the scenarios,” Nichols said.


“We feel it really helps producers, crop consultants and suppliers to make very targeted decisions and not general comments about the DON predictions,” he said.

Using a site-specific risk calculator is more accurate than producing a risk map, he added.

“That being said, guess what? It’s more work. If you are going to run it for your farm, you’ve got to enter some data into the calculator. Therefore, the number of people who use it would not be as high as the number of people who would look at a map.”

The key to DONCast is having accurate and comprehensive weather data. MAFRI has 35 weathers in its network, plus access to data from 25 of Environment Canada’s stations. More stations might have to be added before making DONCast available in Manitoba, Nadler said.

“In my view weather stations are a necessary evil,” Nichols said. “They cost a lot of money to keep up, require a lot of service. If you’re going to get good information out of it, it just takes a lot of dedication. If you can get good-quality data feeds from third parties that will help run models and maybe you get a better multiplier – more bang for the buck.”


WIN’s weather-based forecast programs started as a research project at the University of Guelph’s Ridgetown Campus in 2000 and were spun off into a private company in 2006, Nichols said.

There was a concern farmers might routinely spray their crops to protect them, Nichols said. Being able to assess the risk could reduce pesticide applications. That will save farmers money and also prolong the effectiveness of the pesticides, Nichols said.

WIN also offers programs for sugar beets, tomatoes, corn, apples, tender fruits, strawberries, irrigators and grapes, including telling vintners when they can harvest frozen grapes for ice wine.

DONCast is available in Europe and this year WIN has a program for tomatoes in Portugal and grapes in Spain. [email protected]

About the author


Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.



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