If you are a grower of canola, you’ve most likely come across a flea beetle. Flea beetles are one of the most common pests of canola. In order to grow a successful crop, it is important to have a basic understanding of flea beetles and the management strategies needed to control these pests.
Flea Beetle Damage
Flea beetle damage from feeding may affect crop development depending on feeding intensity, crop stage, and part of the plant that has been damaged. Adult flea beetles may feed on the cotyledons, leaves, stems, and seed pods of canola, mustard and rapeseed. During the larval stages, flea beetles may feed on roots. Heavy populations of flea beetles have potential to cause extensive damage and delay maturity, causing a reduction in yield and seed quality. Yield losses around ten percent are common in areas with infestations.
The economic threshold in canola is when average leaf damage reaches 25%, if flea beetles are still present and feeding. At this point, a foliar applied insecticide is recommended. If beetles are present, it’s important to scout your newly emerging canola plants for damage daily as feeding can advance from 25% to 50% damage in less than a single day, especially in warm and calm weather conditions.
Source: Canola Council of Canada
Identification & Life Cycle
There are three known species that attack canola in Western Canada. These species include crucifer, striped, and hop flea beetles. Of these, the crucifer flea beetle is the most destructive and widespread. Adult flea beetles appear twice in one growing season.
Flea beetles have a single generation per year, overwintering as adults within debris. These overwintering adults begin feeding on canola seedlings when they emerge in spring. Offspring appear in the fall and feed on leaves, stems and seed pods.
Scouting in early spring (May to June) is imperative to catching a flea beetle infestation as overwintering adults emerge to feed. Monitor entire fields, more frequently in warm/dry conditions. Examine cotyledons and leaves of 10 plants in five different locations within a field. Inspect for small, round holes (shot holes) in cotyledons and seedling leaves.
A few simple, good management practices can go a long way in the spring to help prevent, or at the very least reduce flea beetle damage to the crop. A good crop rotation helps promote a good, healthy crop establishment. With a good stand established there will be more plants to spread the impact of flea beetle feeding. Seeding depth is another fairly simple way to give your canola crop the best chance for success. Take the time and set your drill for optimal depth. Fast, even emergence gives the tiny canola plants the best chance to compensate for flea beetle feeding and grow through the most susceptible early cotyledon stages. Finally, canola seed treatments have been a proven method to help reduce flea beetle damage. Standard treatments such as Prosper Evergol and Helix Vibrance will provide some protection against flea beetles. For extended protection there are other treatment options including Fortenza Advanced and the very well-known Lumiderm.
It’s important to monitor your plants in the early spring as flea beetles can do a lot of damage to the emerging crop. Feeding can happen on cotyledons, leaves, stems, and seed pods of canola. Preventive measures can be taken to reduce flea beetle damage including crop rotation, seeding depth, and the careful consideration of canola seed treatments. For further information please contact the SynergyAG rep in your area!