By: Danielle Stephens, MSc, PAg, IPM Agrologist
For information on the red bugs, see Those Red Bugs in My Fields in this issue.
Cutworms have been a concern in some areas again in 2017. Although cooler conditions may have delayed cutworm development in some areas, most later species should be near to pupation by this time. See the 2016 article Cutworm reminder and check out AAFC’s Cutworm Pests of the Canadian Prairies for more information.
Diamondback moth monitoring
Early diamondback moth traps are set up around the province each spring. Very few diamondback overwinter on the prairies; most blow in as adults from the southern states. To ground-truth if it might be a high diamondback moth year, pheromone traps are set up around the province as soon as the snow leaves. If there are favourable to winds bring diamondback moths from the southern United States, the early moths have more time to lay eggs and start building up a population. This spring there were very, very low diamondback moth numbers caught in traps around the province, the highest recorded total was 20 moths in a trap near Yorkton. There were also few favourable winds that might have brought diamondback early. To get information on the wind trajectories, or other insect modelling information done in the prairies, check out early posts by the Prairie Pest Monitoring Blogspot.
Bertha Armyworm moth monitoring is underway in Saskatchewan. Low counts have been reported; so far no counts have exceeded 300 moths per trap, however numbers usually peak mid-July. The Ministry of Agriculture regularly maps the cumulative male moth counts reported from traps at over 180 locations in Saskatchewan. The first map will be available soon and will be updated weekly until the beginning of August. The map provides regional information only, as the male moth number is not going to indicate female moth egg-laying in a particular field. Although high numbers are not expected for this year, if the map shows a higher risk for your area in July, start scouting for bertha armyworms roughly two weeks after peak moth emergence. Although it’s too late to join as a monitor for the 2017 season, if you are interested in monitoring next year please contact firstname.lastname@example.org
Cabbage seedpod weevil
With early flowering in canola fields comes the monitoring for cabbage seedpod weevil. As the 2016 Cabbage Seedpod weevil survey map shows, the weevil continues to be found expanding distribution east and north across Saskatchewan. Begin sweeping canola (and brown and oriental mustard fields) as the crop starts to bud and continue into flowering. As the weevils are moving into the field, getting a representative sample requires sweeping well into the field and sampling from different locations in the field. In canola, the economic threshold is two weevils per sweep. Control products and timing can be found in the Guide to Crop Protection. Refer to the Cabbage Seedpod weevil fact sheet for more information on the biology of this pest.