Diamondback moth larvae have been observed in the Lethbridge area but populations are below economic threshold and are being monitored. The economic threshold for diamondback moth in canola is 100 to 150 larvae per m2 in immature and flowering fields or 200 to 300 larvae per m2 in flowering and podded fields. Scott Hartley, Saskatchewan Ministry of Agriculture, advises that monitoring traps for diamondback moth are being removed in Saskatchewan as trapping results show this insect threat to be low this growing season. More information on diamondback moth is available at the following link: http://www.agriculture.gov.sk.ca/Default.aspx?DN=688b2f99-ad99-423d-900c-c01a1c45d8a1
Bertha armyworm traps continue to be used for monitoring but so far numbers caught in Manitoba and Alberta indicated the risk is low. However, trap numbers in a few locations in Saskatchewan (Nipawin, Melville and east of Watrous in RM 310) have surpassed the low threshold and fields in these areas may need to be watched more closely in the coming weeks. A risk map based on trap counts in Saskatchewan is available at the following link: http://www.agriculture.gov.sk.ca/Default.aspx?DN=e7788ad2-6b94-492a-95aa-3c7af80975aa. The map will be updated regularly as trap results are received.
Cabbage root maggots were again reported in Saskatchewan and Alberta. A number of fields in Alberta had considerable damage (as many as 25 larvae per plant near Fort Vermillion and La Crete, Alberta). In the northern Peace Region, later maturing fields seem to be most affected. It is feared that these high populations will start to impede vascular transportation within the root system and plants will begin to suffer. Drier conditions earlier this spring are generally not favorable for root maggots so it is a bit surprising to see significant damage. There are only cultural management tools for this insect pest. More information on cabbage maggot is available at:http://www.gov.mb.ca/agriculture/crops/insects/fad04s00.html
Lygus populations are being monitored in the Lethbridge area and in the Peace Region of Alberta but so far populations are below economic threshold. There is a range for the economic threshold depending on crop stage and price. More information is available at the following link: http://www.gov.mb.ca/agriculture/crops/insects/fad12s00.html