Flea beetle

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  • Flea beetles: More striped

    Striped flea beetles.

    Striped flea beetles, shown above, seem to have become the dominant species in many regions, with crucifer species harder to find. This has been observed in fields in central Alberta, in particular. Research shows that striped flea beetles emerge earlier than crucifer flea beetles, so one thought is that the crucifers have not emerged, yet. However entomologists expect that most, if not all, of the flea beetles from both species should have emerged.


  • Insect update: Flea beetles, cutworms

    Heavy damage to the first and second true leaves may warrant immediate action if the flea beetles are still present in high numbers. Source: Brian Hall

    Canola is advancing quickly, often emerging in 5 days and starting to sprout its first true leaf in just over a week. Flea beetles are also out in big numbers — enough to warrant a few walks through each field. Seed treatments will provide 3 to 4 weeks of protection for canola that emerges within a week of seeding. Flea beetles need to take a bite of the plant in order to take up the insecticide, so there will be some feeding even while the seed treatment is working. But scouting is still necessary for two reasons: (1) In some cases, intense nibbling by a very large flea beetle population could overwhelm the seed treatment. (2) Seed treatments may wear out in slow germinating or growing crops before the plants are large enough to tolerate much feeding. And (3), the two most common seed treatment insecticides may be a bit less effective on striped flea beetles, so check which one is most common in your field. Most areas of the Prairies have both striped and crucifer flea beetle species.

    Read more for tips how to make the flea beetle spray decision…


  • Insect update: Late flea beetle questions


    Growers are still seeing some insects in their canola crops, including a higher than normal presence of flea beetles. Answers to the following three questions may help with management decisions.


  • Late-season flea beetles

    Flea beetle numbers this late in the season are higher than we’ve seen in years, which could point to higher numbers next spring.

    For this year’s canola crops, don’t take any action unless you see flea beetles feeding on pods over a broad number of acres. Entomologists have not set thresholds for late season flea beetle feeding, but it’s generally believed that numbers have to be very high — perhaps 100 per plant — before economic losses occur.


  • Insect update: leaf rollers, wireworms, bertha, flea beetles

    Leaf rollers probably aren’t worth controlling. Wireworms will live up to 4 years as a larvae and will feed on canola. Bertha monitoring begins. Flea beetles numbers are falling for the season.


  • Are you sure it was flea beetles?

    You maybe went to a field to scout for flea beetles, but take time to look around. Consider all possible causes when you notice uneven emergence, patchy growth and unthrifty plants. Get a second opinion when necessary. You need to know what caused a problem before you can take effective corrective action.


  • Insect update: Flea beetles on volunteer canola

    If flea beetles are already out and on volunteers given the conditions we’ve had, as soon as it gets warm, they will be feeding more aggressively.


  • Striped flea beetles are tough and moving in

    Have you looked closely at your flea beetles lately? Striped flea beetles may not have been a problem in your area in the past, but populations are shifting. This is important because striped flea beetles start feeding earlier, and are more tolerant of seed treatments currently on the market.


  • Insect update: Diamondback moths early, striped flea beetles

    Striped flea beetles seem to be more common each year, especially in the northern canola growing regions. Research suggests that a population of striped flea beetles may do more feeding on seed-treated canola prior to control than a similar population of the crucifer type, so look closely when scouting.


  • Insect update

    Flea beetle spraying continues in Manitoba where crops are advancing slowly due to excess rain and limited warmth. Redbacked cutworms are still causing severe damage in southern Alberta. Some sprayed fields need to be reseeded.


  • Look on stems for flea beetles

    It could be a heavy year for flea beetle feeding, especially since a lot of canola will emerge right at peak activity for the insect. High winds may force flea beetles off leaf tops and down to leaf undersides and leaf stems. This could actually make the situation worse, since it takes just a few bites on a stem to nip off a whole cotyledon or sever the stem. Stem feeding, if it’s happening on a lot of plants, has a lower control threshold than the 25% damage recommended for leaf feeding.


  • Estimating flea beetle damage in canola

    Flea beetles are the most chronically damaging insect pest of canola in western Canada. Direct losses to oilseed production average 8-10% of the annual crop yield, and in outbreak years flea beetles can cause hundred of millions of dollars damage.The nominal economic threshold for flea beetles in canola crops in Canada is an average defoliation level of 25% or more of the seedling leaf area. Images and descriptions in the following article will help growers determine if a foliar insecticide is necessary to protect their canola from flea beetles.


  • Scout the whole field for flea beetles

    Scouting for flea beetles at field edges works early in the season when conditions are cool. With warmer weather, flea beetles will have moved throughout canola fields.


  • When it’s warm, flea beetles go everywhere

    In warmer temperatures, flea beetles are more mobile — so the technique of scouting only at field edges no longer applies. It will be important to scout throughout fields for flea beetle hot spots. Spray only when damage reaches the action threshold — which is 25% of leaf area eaten or damaged. (See the photo […]


  • Flea Beetles – Stem Feeding Noticed

    Flea beetle spraying was reported in many locations across the Prairies. Stem feeding was also noticed in a number of areas. Stem feeding is not a concern if small pitting is occurring. However, if significant stem feeding is occurring (impeding flow of water and nutrients in the stem or stems being clipped off), then a […]


  • Flea Beetles – Be Vigilant with Thin Stands

    It is crucial that fields are scouted thoroughly and often. A heavy infestation on a stressed or thin stand can do significant damage in 24 to 72 hours. Be prepared in case additional control measures are required. The economic threshold for flea beetle control is when 25% or more of the cotyledons are damaged. However, […]


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