We’re likely biased, but entomology might be the most fascinating aspect of agronomy.

To celebrate our tiny friends in the field — beneficial insects — this episode of The Agronomists features not two but three guests: Meghan Vankosky and Tyler Wist, both of Agriculture and Agri-Food Canada, and John Gavloski with Manitoba Agriculture and Resource Development.

Catch a new episode of The Agronomists every Monday night at 8 pm E!

SUMMARY

  • SCI-FI! OK, now that we have your attention, we’re talking beneficial insects. Don’t forget your towel
  • Gavloski wears his work, literally. He’s got a standup shirt on tonight
  • Why are beneficial insects so important?
  • The way you deal with insects and react to insects…
  • Beneficial insects perform more than just pollinating services or eating other insects, they also eat weed seeds and decompose residue
  • What makes them beneficial is the services they provide to humans, no?
  • Biological control: using insects to manage other insects
  • Being called a hippie in this context? Not a bad thing
  • Our one and only clip for the night: Wheat School: Putting a value on the “unpaid army”
  • Putting $ values on beneficial insects? Dr. Haley Catton is working on it
  • Cereal leaf beetle parasitoid: Tetrastichus julis. Gross little larvae (a fecal shield) that leaves these little windows in cereal flag leaves, but is parasitized by a wasp (photo that Shaun had a hard time finding) T. julis has been really effective!
  • Why do cereal leaf beetle always seem problematic in the same fields? Big outbreaks in Ontario
  • CLB overwinter as adults
  • Flea beetle parasitoid, gives false hope (queue sad trombone sound). Two per cent parasitism, not great
  • Bug Wheel of Fortune
  • Wheat head army worm, ok now we’re talking about the “sci-fi” stuff, Cotesia that are bursting out out of the army worm. Carnage.
  • Does the parasitoid (Cotesia) work on all army worm? Cereal army worm, true army worm. Cotesia is a genus, so there are many different species of them
  • Pupae vs larvae. They’re different life stages. Insects that go through a complete metamorphosis go through 4 stages: egg, larvae, pupae, adult. Larvae and adult tend to eat different things. In a grasshopper lifecycle, for example, they go through an incomplete metamorphosis. Egg, nymph, adult.
  • How do we determine what’s beneficial, what’s not?
  • “Anything that eats poops”
  • Grasshoppers. They could be an issue this year, and what eats grasshoppers? A few species of Blister beetles, in the larval stage, will feed on grasshopper nymphs.
  • Bee flies! Also eat grasshopper eggs
  • There’s also a fungus that targets grasshoppers, by causing it to think it’s too hot
  • Grasshopper eggs, look like brown rice grains, laid in clusters, advantageous for egg predators
  • There are more species of ground beetles than there are birds in Canada. Holy smokes. Don’t underestimate this group!
  • With all of these predators of grasshopper eggs, are they eating the eggs in the spring or the fall, or both? How do we protect those predators.The short answer is both times of year. Field crickets are also of value!
  • The Aphid Advisor App can give guidance about thresholds for different aphid populations (it’s got visual guides)
  • Get to know things that predate aphids. Factor those into the threshold.
  • What per cent of insects are beneficial versus pests? Every pest has a predator, and those predators have their own predators.
  • Aphid mummies
  • Meghan is arachnophobic, which is unfortunate being an entomologist
  • Carabid beetles are cool y’all. They’re mobile, they’re found in most crops. They must be protected.
  • Eating worms. #funwithentomologists
  • Some people say if a crop is attacked, it is unhealthy. Any truth to that? Meghan says it’s a mixed bag. John’s example: soybean aphids on soybeans that are deficient in phosphorus
  • What about the new parasitic nematodes that attack corn rootworm?
  • Cold temps and destroying grasshopper eggs? Don’t count on it says John.
  • If these beneficials are so beneficial, how do I build a population of them? Work on economic thresholds. You need to know those. Parasitic wasps like flowering plants so conserve some natural areas around the farm. Don’t use an insecticide just because you can. And don’t panic when your sweep net is full. Selective insecticides are a great tool and some of these newer products don’t cost that much more than the older ones. You also don’t have to spray the whole field — edges, strips. Maybe some trap-cropping (Isothiocyanate from horseradish for flea beetles? No you can’t just pour horseradish around the field)
  • Check out Field Heroes! Other resources: Manitoba has great fact sheets on beneficials and one on how to maximize your ROI using beneficials. Prairie Pest Monitoring website is also a good one! AAFC’s Field Crop and Forage Pests…
  • One last question, wheat midge in Manitoba?

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