Diamondback Moth Monitoring Program in Manitoba - 2018

 

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

Pheromone-baited traps for adult moths were set up at 89 locations in Manitoba in 2018.
  • Until May 20th the highest count from any trap was 2.
  • The week of May 20 to 26th, 3 traps in the northern part of the Central Region and southern part of the Interlake had moth counts that ranged from 29 to 36.   The 2 weeks following this also saw some traps with moth counts in the 23 to 66 range in these regions.
  • The following week, June 10-16, trap counts were generally low (10 or less), with the exception of 3 traps in the Northwest with counts ranging from 19 to 28.   
  • Although diamondback moth arrives on winds from the south, the Northwest region had higher trap catches than the southwest.

The highest cumulative trap count was 108, from a trap near Warren in the Interlake.

Highest trap counts were generally in the Central region and Interlake. Cumulative counts from the Southwest were very low.


Table 1. Highest cumulative trap counts per agricultural region in Manitoba over the trapping period (April 29 to June 30, 2018):

 
Location Count
Northwest
  Bowsman 38
  Sifton 35
Southwest
  Onanole 6
  Miniota 3
  
Central
  Oak Bluff 107
  Morris 83
  Lowe Farm 15
  Bloom 15

 

Eastern

  Seven Sisters 33
  Tourond 15
 
Interlake
  Warren 108
  Teulon 87
  Winnipeg Beach 84
  Balmoral 64
 
 

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).