Cold temperatures hitting Manitoba won’t do much to hurt flea beetles overwintering, leaving the pest as a major concern for canola farmers heading into spring.
Flea beetle numbers were quite high in Manitoba in 2018, making them “probably at the top of the list of (insects) to watch out for this year,” said John Gavloski, extension entomologist with Manitoba Agriculture.
“They seem to overwinter quite well, even in very cold winters,” Gavloski said, and “even if we get bitter cold temperatures, I wouldn’t count on there being significant winterkill for flea beetles.”
The insect doesn’t like to overwinter in fields, he noted; rather, it moves into shelterbelts, hedgerows and other areas where it can hole up under a dense layer of debris.
With large flea beetle numbers likely going into the spring, the next thing to watch will be weather around seeding time.
“If we’re lucky and we get conditions where germination is quick and early-season growth is quick, the seed treatments might be all they need,” said Gavloski. However, any weather-related delays can leave crops susceptible to the insect.
Producers should keep an eye on their fields over the first few weeks of growth, he said.
“Once you get three or four true leaves, the crops can usually compensate well enough and extra sprays aren’t needed,” he said.
Building populations of bertha armyworms in the province could also pose problems in 2019. Some spraying took place in the province’s west in 2018.
Cutworm populations have been high for a number of years already, Gavloski said, noting the pest is typically more cyclical, with numbers tapering off due to natural enemies.
However, given recent cutworm populations, “we seem to be stuck with higher numbers,” he said.
Grasshopper risk is relatively low across the province, with only moderate issues possible in some localized areas, according to forecast maps.
— Phil Franz-Warkentin writes for MarketsFarm, a division of Glacier FarmMedia specializing in grain and commodity market analysis and reporting.