North Dakota State University Extension has found a pest, called the canola flower midge. The midge's larva can injure developing canola plants, leading to reduced yield.

They found the insect, also known as Contarinia brassicola, through using a survey trap, the pests making themselves known in the northern part of North Dakota during 2020.

The canola flower midge’s presence previously has been known in Saskatchewan and Alberta, Canada.

“We obtained 10 pheromone lures from Canada to monitor for canola flower midge for the first time in 2020, mainly along the northern tier of North Dakota,” said Janet Knodel, North Dakota State University Extension entomologist and professor.

A map of the trap survey completed by NDSU. (Contributed photo)
A map of the trap survey completed by NDSU. (Contributed photo)
At the conclusion of their trap survey, 6 out of the 10 pheromone lures were positive for canola flower midge. All of the positive lure sites were in five counties: Bottineau, Cavalier, Pembina, Towner and Walsh. Out of the five counties, Cavalier County had the highest number of trapped canola flower midge.

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Knodel explained that the damage done to the canola crop is mainly done by the larvae itself.

“The larvae is what mainly damages the canola crop. The larvae injures the developing flower and causes swelling and that prevents the flower from opening,” Knodel said.

The damaged flowers then remained closed, causing them to not produce any pods or seeds, which ultimately decreases the crop's yield.

Knodel has some suggestions to keep canola flower midge to a minimum.

“I do believe the infestations are worse right now on field edges. We also know that planting dates has an impact. Early planted canola in mid-May had more midge damaged pods compared to late planted canola, which was planted in early June. So that is one way producers could start minimizing damage, is through (changing) early planting,” Knodel said.

Knodel believes trapping and field scouting will be key.

“Future trapping and field scouting will be essential for early detection and population monitoring of canola flower midge in canola grown in North Dakota,” Knodel said. “This will help the canola industry, so we will know when these midges are present at high populations and pose a threat to canola production in North Dakota.”