Don’t spray weevils too soon: Alberta pest report

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Published: June 21, 2012

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In his weekly Call of the Land pest report, Alberta Agriculture pest specialist Scott Meers says cabbage seedpod weevils are starting to appear and based on conditions so far, quite a few are expected this year, especially south of No. 1 highway.

However Meers recommends not spraying too early.

"We really recommend that producers do not spray their fields prior to the crop coming into flower. The reason for that is the weevils are strongly attracted to crops in flower and if we spray too early we may end up in a situation where we end up with economic levels after a spray application."

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Meers says diamondback moths are coming to the end of the first generation with many moving to the pupal stage, with some concerns about larvae attacking the flowers. "In very rare conditions we have diamondback moths in high enough numbers that the crops wouldn’t actually come into flower." Producers should check if a crop should be coming into flower but is not, Meers says.

However, he says that a fair number of parasitoids are showing up and there will probably be a buildup of the beneficial insects. "If you’re not at economic levels for diamondback don’t spray unless you absolutely have to. There’s a real good chance that the beneficials will build up and take this population out."

Bertha armyworm traps are out but so far very few have been spotted. "At this point we have nothing showing up in hot spots yet.  But that can change very quickly and we’ll be watching the map closely as we progress through the monitoring season."

Meers said parts of the province with grasshopper issues from previous years may have them again and producers should be scouting to see if early control is needed before they spread out.

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