By Carter Peru, AAg, Integrated Pest Management Agrologist, Regina
Diamondback Moth Survey
This year, 45 diamondback moth (DBM) pheromone traps were monitored across Saskatchewan. Overall, cumulative counts were low in most of the province, but some sites did have higher counts. The highest cumulative count was observed in the monitoring site near the Meadow Lake area, which caught a total of 521 DBM. The second highest cumulative moth count was in the Cadillac area where the cumulative moth count was 151. DBM moth is a pest of concern for many brassicaceous crops, including canola and mustard. Although the trap counts cannot be used to predict crop damage, the pheromone traps provide an early warning of the presence and abundance of moths. The larvae causes crop damage so scouting for moth larvae must be done in order to determine the potential for crop damage and to apply economic thresholds.
Bertha Armyworm Survey
Bertha armyworm (BAW) counts were submitted by cooperators around the province using pheromone traps to catch adult moths. These counts are used to create cumulative moth count maps are used as a risk indicator for BAW infestations. Adult worms do not cause crop damage, which means scouting for the damaging larval stage is necessary to determine if the economic threshold has been reached. This year, 287 pheromone traps were monitored in canola crops throughout the province. Overall, cumulative moth counts were low for most of the province. High numbers of moths were seen in a small area in the East Central region of the province, near Humboldt. Moderate amounts of moths were caught in a small area North of Saskatoon, as well as in the South East near Wolseley.
Pea Leaf Weevil Survey
During the pea leaf weevil (PLW) survey, surveyors assess field pea crops for notching damage. The amount of feeding notches is recorded and used to create the annual PLW map to provide an indication of weevil populations as well as their distribution in the province. Results of the 2020 survey will be available in the near future.
Surveying begins when a majority of grasshoppers are in the adult stage, which is usually at the end of July to mid-august. Only adult grasshoppers are counted during this survey, since they are considered the greatest reproductive threat to the following years population. Grasshoppers will feed on all types of crops including, legumes, oilseeds, pulses, forage crops and many others. Approximately 1200 sites are surveyed for population densities. The data is compiled in order to create a forecast map for the following growing season. The map depicts the grasshopper densities calculated during the survey. The 2021 grasshopper forecast map will be posted in the near future.
The ministry leads or participates in many other insect pest surveys. If you would like more information, please contact Carter Peru by email or at 306-787-4670. To access insect maps like the ones mentioned above, visit the ministry website.