Top 4 tips to conquer flea beetles this spring

Flea beetles are becoming an endemic problem and farmers have identified these pests as one of their greatest production risks.

We're entering another growing season and pest management is key to ensuring your crop's success. I'm sure you can relate to the annoyance and destruction that flea beetles bring but we're here to help you in the battle against these pests. Flea beetles have been an increasing concern in all areas of the prairie provinces with 80% of growers identifying this pest as their greatest economic risk in canola, an increase from 74% in 2020.

Flea beetles first attack plants in the seedling to early vegetative stages. This type of damage to a crop early on can have significant impacts on the rest of the growing season, ultimately affecting yield. Understanding the habits of these critters and how you can manage them will help ensure your young crop gets the best start possible.

Flea beetles feed on plants of the mustard family grown across the prairie provinces and there are three main species to watch for in Western Canada:

• Cruciferous flea beetle
• Striped flea beetle
• Hop flea beetle

What you should know about flea beetles (Know thy enemy!)

Flea beetles typically only have one generation per year. Of the three species listed above, hop flea beetles are the first to emerge. The adults overwinter near the soil's surface in leaf litter and emerge in the spring, but you may also be able to spot their offspring in the fall, chewing on canola pods. 

All weather conditions affect their habits:

• Cool, damp weather slows them down (along with crop growth).
• Sunny, warm, dry weather encourages their feeding activity, and droughts in parts of the Prairies over the past few years have encouraged them.
• Windy weather (which is quite common) causes them to feed more on the stems than the leaves.

Scout for flea beetle activity early on. Crop thinning and growth reduction caused by flea beetle feeding are the most severe in the first two weeks after crop emergence. It's not uncommon to see a 10% yield loss from a significant infestation, even with insecticide treatments.

What can you do to minimize crop loss from flea beetle infestation? Follow these four tips:

1. Use seed treatment. 

It's a common practice to use seed treatment on canola, and all seed varieties will come with a base treatment. If you're expecting high flea beetle pressure, consider using an add-on seed treatment for extra control. Add a product like Buteo™ Start to the base seed treatment to offer stronger protection.

2. Keep an eye on seeding conditions.

Seeding into a warm, moist seed bed will encourage canola development and move the plants out of the susceptible stage more quickly. Conditions that slow plant development will provide a longer feeding period for flea beetles. Make sure to scout early on. Once the crop is at the four-leaf stage, feeding will have minimal impact on yield.

3. Assess the damage

• Check canola fields frequently as damage can occur rapidly.
• Make sure to scout the newest leaves during plant growth, as these tend to be flea beetles' preferred meal. The action threshold on canola plants for flea beetle damage is 25% defoliation with insects continuing to feed.
• If cotyledons are chewed but newest leaves are showing little feeding, the threat may have subsided, or your seed treatments may be working.
• Check for stem feeding, especially if conditions have been cool or windy, as this will drive flea beetles down to leaf undersides and stems.
• Continue to scout fields until canola reaches the four-leaf stage. If you're unsure if the damage has reached the economic threshold, take pictures of the damage and send it to your Cargill rep or Market Development Agronomist. A second opinion may not only save you money but could also save beneficial insects in your field that can help your crop.

4. Spray, if necessary.

If damage to your field is past the action threshold and flea beetle pressure is high, use a foliar insecticide. Pounce®384EC, Decis®25EC, and Perm-UP®3.2EC are all registered for use on flea beetles in canola for the 2023 season. Remember to always read and follow label instructions when using any pesticide product.

If you have any questions about flea beetles, or would like more information, please reach out to your local Cargill rep.

^{Buteo™ Start is a trademark and Decis®25EC is a registered trademark of the Bayer Group used under license. Pounce®384EC is a registered trademark of the FMC corporation. Perm-UP®3.2EC is a registered trademark of United Phosphorous, Inc.}