Diamondback Moth Monitoring Program in Manitoba - 2020


Diamondback moth does not overwinter well in the Canadian prairie provinces, but large numbers can potentially blow in. If conditions are favorable for their survival and reproduction when they arrive, and if natural enemies do not limit population establishment, populations can increase.

Pheromone-baited traps (Fig. 1), which attract the male moths, are established for a 6-8 week period from early-May until late-June to detect the arrival of populations of diamondback moth early in the season. The cumulative counts from the traps can not predict what levels of larvae will be, but can be used to determine regions of the province where increased attention for diamondback moth is recommended when scouting fields.

Fig. 1. Trap for diamondback moth                                 Fig. 2. Diamondback moth on insert of trap

 Summary (as of July 7, 2020)

Pheromone-baited traps for adult moths have been set up at 84 locations in Manitoba in 2020.
  • Highest counts generally have been in the Eastern regions and South Interlake.
  •  Several traps in the Eastern region and South Interlake had elevated counts through June.
  • There have been no high counts yet in Southwestern Manitoba, with the highest cumulative counts being 15.

The highest cumulative trap count so far is 400 from a trap near Lac du Bonnet in the Eastern region. It appears a populations of adult diamondback moth were blown in and deposited in the southern Interlake and Eastern region.     

Table 1. Highest cumulative trap counts per agricultural region in Manitoba over the trapping period (May 3 to June 30, 2020): 

Location Count
  The Pas 123
  Bowsman 50
  Bowsman 31
  The Pas 30
  The Pas 24
  Hamiota 15
  Brookdale 7
  Foxwarren 5
  Shilo 4
Rivers, Carberry 3
  Gladstone 57
  Reinland 52
  Portage la Prairie 15
  Winkler 12
  Miami 11
  Kilarney 10
  Lac du Bonnet 400
  Whitemouth 372
  Stead 263
  Beausejour 189
  Ste. Anne 40
  Warren 241
  Vidir 137
  Balmoral 127
  Gunton 106
  Geysir  96


Guidelines for monitoring larvae of diamondback moth can be found at: http://www.gov.mb.ca/agriculture/crops/insects/diamondback-moth.html

                                            Fig. 3. Diamondback moth pupa (left) and larva (right).