Insect numbers are on the rise across Western Canada and farmers should scout fields to protect against unnecessary losses.
Grant McLean, crop management specialist with Saskatchewan Agriculture, says the emergence of many insects was later than usual this year due to a cool, late spring.
Many crop pests will become more visible in the next two to three weeks, although grasshoppers and alfalfa weevils are already causing damage in parts of Saskatchewan and Manitoba, he said.
“Insect development is usually temperature dependent so their populations usually coincide with the crops’ development,” said McLean. “In general, crop development and insect development usually mesh pretty closely.”
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In Manitoba, alfalfa weevil damage is already widespread, said provincial entomologist John Gavloski. Numbers are high in many alfalfa fields and spraying is common throughout the Interlake region.
Weevils are also becoming more common in Saskatchewan, said McLean.
Across the Prairies, grasshopper damage is the most prominent insect threat for 2009.
Significant hopper numbers are being reported throughout south-central and eastern Alberta, with particularly high populations in drought-affected areas along the Saskatchewan- Alberta border and in southwest and central Manitoba.
Gavloski said producers should check field edges and other areas where young hoppers emerge to determine if populations warrant chemical control.
In Saskatchewan, high populations are reported at Dinsmore, Hodgeville, Gravelbourg and Assiniboia areas, McLean said.
“That’s the biggest concern in Saskatchewan right now is the grasshoppers, particularly in the areas south and east of Swift Current … west of Outlook and south and west of Rosetown.”
According to Gavloski, populations of most other insects are relatively low in Manitoba.
McLean said in Saskatchewan a second flush of canola plants is providing new fodder for late-emerging flea beetles.
“Because we have such a wide range of crop staging in many canola fields, the challenge for a lot of producers is determining whether or not they want to protect those smaller plants,” McLean said.
According to McLean, some canola growers who had decent germination early in the growing season may be better off sacrificing newly emerged canola seedlings, which can cause uneven ripening, grade losses and problems at harvest time.
