The Diamondback Moth is a pest found in most canola fields of the County during any given year. However, it is generally found in well-below threshold numbers.

Where do They Come From?

The moths are mainly blown in on southeast winds from Texas and California. There is research showing the insects may overwinter in Western Canada if the conditions are favourable for them.

What are the Risks?

The larvae, which hatch in early July, are voracious feeders and in large numbers, can cause a great deal of damage in a canola crop. They feed on leaves for the first stages of their lives, then move upward to the flowers which is where the greatest damage occurs.

How are They Monitored?

This pest is monitored here in the County using pheromone traps in the early spring.

What to Look For

   Diamond back pupa and larvae               Diamond back Moth           Diamond back larvae feeding

       pupae and larvae                                             larvae                                                 feeding larvae                            

   Diamond back adult                Diamond back adult 

          Adult moth                                                  Adult moth


Canola is a member of the Brassica family which also includes cabbage, stinkweed, lambs quarters, etc. All these plants are hosts to the Diamondback Moth. There are steps you can take that may reduce or eliminate the threat of these insects in canola crops:

  • Control all host plants, including volunteer canola;
  • Check Alberta Agriculture for local insect forecasts;
  • Scout fields from early May and throughout the growing season; and
  • Consider recommended insecticide only when threshold of larvae (20-30 per square meter) is reached. This will minimize the impact on beneficial insects.

Related Links

Canola Council Diamondback Moth management

Real Agriculture Understanding the Diamondback Moth

Building a Diamondback Moth Trap