b'WHEAT MIDGEThe Value of ValidationMonitoring the unpredictability of wheat midge populations.AN ESTIMATED 35 per cent of wheat planted in Western Canada is midge tolerant and this widespread availability has provided a solid agronomic tool against the midge. And yet, Tyler Wist, Agriculture and Agri-Food Canada (AAFC) field crop entomologist, is discovering how much theres still to learn about wheat midge to control its impact on wheat crop yields and quality.Following Up on ForecastsEvery year, Alberta produces a midge forecasting map to provide insight for growers before they make seed purchases in the spring. The maps are built on midge cocoon populations gathered from soil core samples in close to 300 field locations. Midge populations are mapped, and colour coded from green (low risk) to redcollected from soil samples in fall 2021 Wheat midge can last up to 13 years in (high risk) for their potential for damagingprobably based on the exceptionally hotthe soil and still be viable, he says.midge emergence the next spring. and dry summer in 2021.Wist will be continuing the Midge In 2021, Wist began coordinatingSo, if you were a wheat grower, youBuster project to continue to gather Midge Bustersa collaborative fieldmight have looked at that and thoughtvaluable insights.project with SeCan to distributethere isnt much risk of wheat midge, pheromone traps and gather insight tosays Wist, Best Practices Still the Best help connect the dots between midgeAnd yet, thats not really how thingsApproachforecasts and actual midge emergenceplayed out. The data we collected inPlanting midge tolerant wheat is the best in the spring (see it on Twitter2022 has actually raised more questionsagronomic practice against damage from #midgebusters). than answers about wheat midge, withthe unpredictable pest. The project collects field data frommore midges caught in 2022 on averageIf you dont plant midge tolerant wheat, pheromone traps and the correspondingcompared to 2021, Wist adds. and the population reaches the economic crop stage at around 65 site collectionIn 2022, in locations with adequatethreshold of one female per five heads of locations in Western Canada. The datarainfall, they were finding male midgeswheat, the yield loss starts at 15 per cent is used to follow up on forecastingon traps in locations they wouldnt haveand goes up from there, says Wist. predictions to determine if wheat midgeexpected if they just relied on the forecastGrowing midge tolerant wheat emergence aligns with the susceptiblemaps showing green or low risk. requires growers to sign a stewardship stage of the wheat to cause economicThe forecasts are a great measureagreement to ensure the integrity of the damage.of what could happen, but not alwaystechnologyand ensures every bag The pheromone traps and crop staginga measure of what will happen, sayscontains a 10 per cent refuge on non-provide critical validation to compareWist. And 2022 up there was a lot ofresistant seed to reduce the likelihood with the soil core forecast and AAFCunexpected unpredictability with midgeof wheat midge developing resistance to emergence maps to see whats happeningpopulations.the Sm1 gene.in real time, says Wist. The Sm1 gene is the only single resistant Its All About the Weather gene thats used by breeders against wheat Green isnt Always GreenWhen it comes to 2023, Wist cant makemidge, and the only one available in The midge forecast maps for 2022 wereany predictions. Midge populations arewheat varieties in Canada, he says.showing mostly green indicating lowall weather dependant, and he describes The Midge Wheat Tolerant populations of overwintering cocoonsthem as a ticking time bomb in the soil.Stewardship Team50seed.ab.ca'