The Agronomists, Ep 100: Drs John Gavloski and Boyd Mori on fighting flea beetles

Canola has the toughest start of any crop in Western Canada, if only because it’s the preferred food of striped and crucifer flea beetles that lie in wait for the first sign of green each spring.

Flea beetle pressure has become so heavy that seed treatments and a foliar spray can, at times, not be enough to save the fledgling crop. What more can be done? To answer that question, host Lyndsey Smith is joined by Drs. John Gavloski, with Manitoba Agriculture, and Boyd Mori, with the University of Alberta.

Thank you to our show sponsors: ADAMA Canada, FMC Pre-school, and the Canola School!

SUMMARY:

• What insects are on John’s shirt?
• What is Boyd working on? Alfalfa weevil, flea beetles, and some midges
• Flea beetles, aphids, and grasshoppers are top of mind in Manitoba
• Let’s go with lifecycle first — flea beetles overwinter as adults
• There are some good ones, if you can believe it
• But we focus on striped and crucifer
• Adults emerge in late summer
• Does it matter to know the difference?
• Used to think striped was more northern, but they have spread
• Striped usually emerge first, are less impacted by neonic seed treatments
• So far, we don’t have resistance to foliar applications, that we know of
• Does root feeding cause economic damage? It can, but not that we notice in-field
• Does fall numbers equate to spring levels? Not really. Ugh, but why? So many reasons
• We don’t know where striped flea beetles hang out in the fall. Sneaky!
• Really high populations can look like “resistant” populations, i.e. neonic seed treatments
• Resistance happens with a genetic change. There’s no evidence of genetic change, but there is variability in the effectiveness of neonics
• It’s not protein or sugar that attracts the beetles — it’s the glucosinolates and flea beetle pheremones
• Like bad cologne
• Clip 1: Canola School: Seeding depth with Jack Payne
• What about tillage? Zero till decreases feeding, but not eliminates. Less damage, but not no damage
• Uneven emergence can be deadly, as the flea beetles swarm. More beetles on fewer plants
• Flea beetles lie in wait, y’all
• The jump and fly! Can move quickly
• Have to balance seeding rate with disease pressure, seed costs
• 25 per cent feeding damage is the trigger to call in the sprayer, if you are going to spray
• Let’s talk about the lack of access, possibly, to lambda-cy (Matador and Silencer)
• What do we have with foliar applications? There are some: three major groups of actives
• Examples: Decis, Ambush, Pounce, etc., as trade names. But there is concern about using the same active multiple times in a year
• Other insect issues later in the season….number of sprays?
• Biggest issue may be access
• What about beneficials? There are natural enemies? Yes, but nothing that prefers or feeds well on flea beetles
• There is some parasitism, but flea beetles are not natural to Canada (they came from Europe, thanks)
• What about strip spraying? Edge spraying
• Trap crops?
• What about seeding LATE, like really late
• What really matters is how fast the canola goes from emerged to three- to four-leaf stage. You have about three weeks of neonic protection
• The faster more even emergence happens AND how quickly the plant grows is the real key
• Some are seeding later, and some years it works well
• Where is hairy canola at? Still being researched!
• Can we change the glucosinolate mix of the canola plant?

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