Events Icon


View Events
Events Icon

Smart Partner Program

Learn More
Subscriber Login

Watch for early cutworms

Bug of the Month

Cutworm on the snow

By Hector Carcamo, Vincent Hervet and Bob Byers

The earliest active cutworm species on the prairies is the early cutworm (Euxoa tristicula). It is a native species that had an outbreak in beet fields near Taber (around 1970 if I recall properly). Vincent Hervet Ph.D., Agriculture and Agri-Food Canada, doesn’t believe that it has caused serious problems since.

He warns a more serious species for concern is the army cutworm, Euxoa auxiliaris. It overwinters as larva (various stages, but many will be nearly fully-grown) and therefore can cause significant damage as soon as temperatures rise. It lays its eggs in loose soil in late August-early fall. It especially likes fields with some green vegetation, so these will have a higher risk.

Redbacked cutworm adult Photo: John Gavloski, Manitoba Agriculture

The most problematic cutworm species on the prairies at the moment seems to be the redbacked cutworm, but this one overwinters as eggs so will occur a little later. Darksided and dingy cutworms often occur with it. Eggs of redbacked and darksided cutworms are laid in early fall, typically in loose or sandy soil.

Cutworms overwinter as mature older larvae and near the soil surface. So they wake up earlier than a wireworm that overwinters probably deeper down in cooler soil. Cutworms take a summer holidays in the mountain in mid summer when it gets too hot.

For extensive information and reference, download the guide Cutworm Pests of Crops on the Canadian Prairies