Diamondback Moth Monitoring Program in Manitoba - 2021


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 June 15, 2021)

Pheromone-baited traps for adult moths have been set up at 98 locations in Manitoba in 2021.
  • Trap counts were generally low until late-May. Since then some moderate counts have occurred in traps in the Northwest, Central, Interlake and Eastern regions.
  • Only 59 traps have caught any diamondback moths.

The highest cumulative trap count so far is 135 from a trap in the Northwest region. In spite of some strong winds from the South, a lot of traps still have low numbers, with a few traps showing moderate counts.


Table 1. Highest cumulative trap counts per agricultural region in Manitoba over the trapping period (April 25 to June 15, 2021) 


Location Count
  The Pas 135
  Bowsman 52
  Makaroff 39
  Grandview 33
  Grandview 29
  Minto 28
  Boissevain 15
  Fairfax 11
  Carberry 8
Douglas 7
  Edwin 35
  Haywood 32
  Ninga 15
  Starbuck 12
  Culross 12
  Austin, Darlingford 7
  Stead 51
  Beausejour 42
  Hadashville 20
  River Hills 19
  Tourond 13
  Selkirk 112
  Clandeboye 24
  Vidir 21
  Arborg 20
  Stonewall  14


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).