Looking For Aliens: New Arrivals and Potentially Invasive Insects to

Watch for in Crops in Manitoba John Gavloski, Entomologist, MAFRI

Topics

• Cereal Leaf Beetle• Swede midge• Cabbage seedpod weevil• Western bean cutworm• Corn rootworm

Cereal Leaf Beetle

• Native to Eurasia

• First reported in– North America in Michigan in 1962– Utah in 1984; Montana in 1989– Alberta in 2005– Saskatchewan in 2008 (in 3 fields in

southwest corner)– Manitoba in 2009 (Northwest)

Cereal Leaf Beetle Larva

Cereal Leaf Beetle

Cereal Leaf Beetles in Northwest Manitoba in 2009

• 12 fields Surveyed• A total of 18 cereal leaf beetle larvae found in 4

of the 12 fields:• 10 - East of Swan River • 3 - East of Swan River • 2 - about 10 miles west of Swan River• 3 – close to Benito• Feeding damage was reported as insignificant.

Tetrastichus julis

Photo credits: T. Larson, AAFC

Swede Midge

• Hosts: cruciferous plants

Photo credits: Dr. R.H. Hallett, University of Guelph

Swede Midge in Canada

• Crop damage reported as early as 1996 in Ontario. Confirmed as Swede midge in 2000.

• Found at 3 locations in Saskatchewan in 2007.

• Manitoba: found at 2 sites in 2008– 1 adult in trap in canola at Glenlea– 1 adult in trap in broccoli at Portage la Prairie

The Canadian Entomologist: 2001. 713-715.

Swede Midge

• Swede midge damage to a young plant prior to stem elongation can result in no racemes, flowers or pods being produced.

Photo courtesy of Ontario Ministry of Agriculture, Food and Rural Affairs

Swede Midge

• Swede midge injury to plants already bolted results in all pods forming from injury site, causing a bouquet of pods. Yield is not impacted in this case.

Photo courtesy of Ontario Ministry of Agriculture, Food and Rural Affairs

“Bouqueting” injury in canola

• Several insects can cause this type of injury to canola.– Lygus– Abiotic injury to the growing tip of the

developing flower head.

Cabbage Seedpod Weevil

• Native to Europe• Detected in

– Washington state in 1936.– Alberta in 1995– Saskatchewan in 2000.

• Currently not in Manitoba

Increasing its range in western Canada to the north and east at a rate of about 60 km per year.Dosdall et al. 2002. Can. Entomol. 403-418

Crop damage by Cabbage seedpod weevili) destruction of flowers and buds by adults

Photos courtesy of Lloyd Dosdall – University of Alberta

Crop damage by Cabbage seedpod weevilii) larval feeding on developing seeds

Photo courtesy of Lloyd Dosdall – University of Alberta

Crop damage by Cabbage seedpod weeviliii) new generation adults feeding on pods

Photos courtesy of Lloyd Dosdall – University of Alberta

Crop damage by Cabbage seedpod weeviliv) secondary fungal invasion of infested pods

Photo courtesy of Lloyd Dosdall – University of Alberta

Western Bean Cutworm

Photo credits: Chris DiFonzo, Michigan State University

Entry holes from WBC larvae. Feeding damage to corn ear by WBC larvae.

Western Bean Cutworm

• Native to North America• Started to spread to new areas since 2000

– Overwintering further north and east.

Western Bean Cutworm

• Western Bean Cutworm Larva. Note the two broad brown bands on the pronotum (indicated by arrow).

Photo credit: Marlin Rice, Iowa State University

Western Bean Cutworm

• Figure 1. Adult Western Bean Cutworm. Note the distinct markings on the wings (indicated in photo).

•Photo credit: Marlin Rice, Iowa State University

Western Bean Cutworm and Bt Corn?

• “Spread from its historic range has coincided with the widespread use of hybrids with the YieldGard Corn Borer trait, which has activity against corn borer and corn earworm, but not western bean cutworm.”

Western Bean Cutworm and Bt Corn?

• “These studies suggest that by removing certain damaging species, the hybrids with the YGCB trait created a "void" for a new insect species to thrive.”

• “In these studies, the damage from the new insect on hybrids with the YGCB trait was worse than damage from the old insect species on the non-transgenic hybrid.”

• “This phenomenon of "pest replacement" may help explain the recent, rapid range expansion of WBC across the Corn Belt from Nebraska to Ohio.”

Corn Rootworm larvae

Photo courtesy of Ontario Ministry of Agriculture, Food and Rural Affairs

Northern Corn Rootworm

Photo courtesy of Ontario Ministry of Agriculture, Food and Rural Affairs

Northern Corn Rootworm Specimens from Manitoba

• 5 specimens collected– 3 in August 1997– 1 in September 1997– 1 in August 1998– All collected from St. Charles Rifle Range– Suspect these were late season migrants.

Distribution of Northern Corn Rootworm

Source: University of Minnesota “Radcliffe’s IPM World Textbook”

Western Corn Rootworm

Photo courtesy of Ontario Ministry of Agriculture, Food and Rural Affairs

Status of Western Corn Rootworm – from NAPIS Pest Tracker