|How long will my seed treatment protect the plant?
Seed treatments may help to protect the newly emerged seedlings. As the seedling grows the effect of the seed treatment will begin to wear off and may be no longer effective by the second true leaf stage. Under light infestations of flea beetles and good growing conditions the seed treatment may provide enough protection for the crop to outgrow the feeding damage. Delayed germination may have decreased the effectiveness of the seed treatment so control may not last as long.
When should I control the flea beetles?
The threshold for flea beetle control is when approximately 25% of the leaf area has feeding damage. The leaf will look very ratty at this stage. No control may be needed if the damage is less than 25%and there are good growing conditions present. Flea beetles can thrive under poor growing conditions such as warm dry weather. The crop will be slow growing and may sustain more damage, increasing the need for chemical control to prevent crop damage and yield loss.
Can I tank mix my chemical with my herbicide?
Several insecticides are tank mixable, but check with the product label for approved mixes before spraying. Contact the appropriate chemical company or your local chemical rep to obtain information on approved tank mixes.
Can I re-seed my canola crop after my first crop has been destroyed?
Concentrated feeding of flea beetles usually occurs from mid-May to late June, so your second crop can be in danger of being attacked by flea beetles. Once the first canola crop has been destroyed the flea beetles will move to another source of food, which can be a nearby oilseed crop or nearby weeds surrounding the field. You can reseed your canola, but consider a seed treatment for flea beetle protection and monitor crop for threshold levels. Remember that your crop has been delayed and will have to be watched carefully for infestations.
Crucifer Flea Beetle Biology (North Dakota State University)
Prepared by Ag-Info Centre, Alberta Agriculture and Forestry.