Flea beetles are one of the most detrimental insects for the early stages of canola, but new research sheds some light on how seeding date can be used to get ahead of this pest.
In this Canola School episode, Hector Carcamo, research scientist at AAFC Lethbridge, shares some interesting results on how two species of flea beetle differ in their life cycles, how region dictates which species will dominate, and how seeding date may help a canola crop out when it comes to the pest.
In southern Alberta, the risk of flea beetle damage can be escaped by planting early, as long as there aren’t too many striped flea beetles. Going further north to the Calgary or High River area, there are more striped flea beetles, which are more active in early spring.
In areas where there are more complex habitats, there may be more refuge spots for beneficial insects and predators of flea beetles, says Carcarmo.
“It looks like the more canola there is in the region, the fewer flea beetles we find in the fields, which sounds a little bit counterintuitive perhaps, but it probably has to do with the ability of flea beetles to fly long distances,” says Carcamo.
If there’s a field of canola that’s isolated from other canola fields, the flea beetles will congregate in that field, but if there are a few fields of canola close together in the area, the population will disperse more evenly over all of the fields.
Carcamo says that ideal conditions for flea beetles, when they do the most feeding is during hot, dry spells. If there are colder temperatures in the forecast, the flea beetles aren’t able to fly and they hop slowly into a field, which may be advantageous for control measures around field edges.
Check out the full conversation in the video, story continues below:
In terms of predicting how severe flea beetle populations will be in a certain area, particularly with conditions prior to the previous winter, is an area where Carcamo admits more research should be done. He says that flea beetles are somewhat difficult to forecast, and regional risk maps don’t exist for them.
To determine how to forecast for them locally, Carcamo says a few key factors need to be examined:
- the population levels need to be documented;
- summer conditions that affect populations should be noted;
- identify the main natural enemies that reduce numbers need to be identified;
- determining the health or physiological status of the pest before overwintering; and,
- what the spring conditions are.
Accurate estimates of damage levels in canola is also a key piece of information going forward. Additional research currently underway in Lethbridge by Justin Pahara, research scientist at AAFC, involves using artificial intelligence to determine a more objective measure of flea beetle damage in young canola.