In many barley fields, the unnatural yellow color was likely attributed to severe scald and net blotch, which were prevalent in 1986. Economic threshold From 5 to 25 aphids per stem warrants chemical control action, that is, the economic threshold is dependent on the stage of crop growth, the health of the crop and growing conditions. Abundant predators and parasites should enable greater populations to be tolerated. The species has been abundant in hot dry weather. Cool weather may prevent population increases.
Rain can wash migrating aphids out of the air.
Predators, especially lady beetles, have prevented population increases and controlled outbreaks. The user of this information agrees to the terms and conditions in the copyright and disclaimer . Her Majesty the Queen in the Right of Alberta. All rights reserved.