Ent 222: Exploring the Biology and Ecology of Cotarinia pests of Canola in North America

What are three key components of insect ecology?

1. Behavioural: mate finding, host plant selection, predation/scavenging

2. Chemical: pheromones, microbial volatiles

3. Molecular: transcriptomics, genomics and population genetics

How much canola is grown in Canada?20-22 million acres

20-22 million acres

What are some key canola pests?

• Flea beetles

• Crucifer flea beetles

• Cabbage seed pod weevils

• Bertha armyworm

• Diamondback moth

• Swedge midge

What is Swedge Midge?

Contarinia nasturtii

Host plant: Brassicaceae; Cabbage, Broccoli, Collard Greens and Canola

Very damaging; a single larvae can reduce the marketability of the host

How did swedge midge spread in NA?

2000s present in Ontario

2001 spread to Quebec

2004 spread to NY

2005-2006 spread to the Eastern US (quarantine zone opened)

2007-2008 probable spread to Saskatchewan and Manitoba ??

What did the “swede midge” galls on prairie canola look like?

More robust, hairy and not damaging with less generations per year

How did they experiment on the prairie “swede midge”?

2016: Experiments to determine the lifecycle

Emergence cages with pheromone trap … caught more midges but no males were captured on the pheromone traps

But there were no issues with the same traps in Eastern Canada …

So they caught and reared the larvae

The midge had different antennae then the actual wheat midge; the 3rd flagellum was elongated

They used DNA barcoding to further identify the species

It only had a 91% sequence similarity to the swede midge

… This was a new-to-science species

Canola flower midge: Contarina brassicicola

Therefore Swede midge is not in the prairies

What is the ecology of the Canola flower midge?

Distributed across the prairies

Seasonal emergence in 1st year canola in the summer

weather is a key driver as well

What damage does the canola flower midge cause?

Causes flower scarring

Damage is more prevalent at edge

Larvae have also been found in pods; in previously damaged and vulnerable pods

Is the Canola flower midge native or invasive?

Native likely