Winnipeg – Cold temperatures hitting Manitoba won’t do much to hurt the flea beetles overwintering, leaving the pest as a major concern to watch for for canola farmers next 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,” said Gavloski adding, “even if we get bitter cold temperatures, I wouldn’t count on there being significant winterkill for flea beetles.”
He noted the insect doesn’t like to overwinter in the fields, rather it moves into shelterbelts, hedgerows and other areas where it can get under a dense layer of debris and protect itself from the elements.
With large flea beetle numbers likely going into the spring, the next thing to watch will be weather conditions 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.
Gavloski said producers should keep an eye on their fields over the first few weeks of growth.
“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 army worms in the province could also pose problems in 2019, with some spraying in the western part of the province in 2018.
Gavloski said cutworms have been high for a number of years already. That insect is typically more cyclical, with numbers tapering off due to natural enemies. However, cutworms have already been high for a few years and “we seem to be stuck with higher numbers,” he said.
The grasshopper risk is relatively low across the province, with only moderate issues possible in some localized areas, according to the forecast maps.