Come walk the crops with us- Diamondback moth trapping and insect monitoring
Sometimes white delta traps set up on field edges can be seen from the road if you are driving around in the spring.
These are pheromone traps used to monitor for diamondback moth arrivals. Levels of diamondback moths collected in traps can be used as a prediction of diamondback larvae presence later in the season.
Monitoring at a regional level starts early in the spring and continues for about six weeks to determine the arrival of the first moths in a region. Numbers are reported weekly by cooperators and compiled by provincial staff. Updates are provided on a regular basis.
Mature male moth from a trap.Diamondback moths do not overwinter here in Saskatchewan in significant numbers; rather they arrive here from southern states on southerly winds that can come up from Texas, California, Nebraska, and other southern states.
The Prairie Pest Monitoring Network (PPMN) has information on the number and trajectory of these winds that can be used as a tool to help predict when the moths can be expected to arrive in Saskatchewan. Wind trajectories have been measured for more than 15 years to track diamondback moth arrival.
The PPMN has a weekly newsletter that contains wind trajectory maps and other insect information. Aster leaf hoppers can also arrive on these wind trajectories, and cooperators can monitor for them in conjunction with the diamondback moths. Diamondback Moth Larvae- these are shaken off of plants later in the growing season - usually in July.
The traps will monitor for early arrivals of the adult moths, but they can continue to arrive as the season progresses.
We monitor for diamondback moths because the larvae can cause damage to canola and/or mustard when these crops are podding. In Saskatchewan, we can have up to three overlapping generations of the adult moths that lay eggs on leaves; the larvae then feed on canola or mustard plants. Larvae feed on the leaves, flowers, and developing pods, and strip bark from the stems and leaves. Scouting for larvae is done later in the season. Frequent scouting is very important, since there can be up to three generations in a season.
In addition to the diamondback moth monitoring program, cooperators from around the province also volunteer to monitor for bertha armyworm, which we will talk about in a later crop walk. Ministry of Agriculture staff partner with Agriculture and AgriFood Canada staff to monitor for swede midge throughout the entire growing season, and Saskatchewan Crop Insurance Corporation (SCIC) works with the Ministry to survey for grasshoppers. The Ministry also surveys for a number of pests in conjunction with our partners, including pea leaf weevil (which we will talk about on a future crop walk), cabbage seedpod weevil, and aster leafhoppers. The results from many of these surveys and monitoring programs result in the annual pest forecast maps that are released during the winter months.
If you are interested in learning more or becoming a cooperator in this program, you can contact the crops extension specialist in your nearest regional office.