Soybeans are beginning to flower and corn is waist high in parts of Ontario, and it’s not even July.

Crop staging, lush and humid canopies, and field history all play a key role in disease development and suppression, and our guests for this episode stress the importance of genetic selection and scouting as the first lines of defense against crop disease.

For this episode of The Agronomists, host Lyndsey Smith and her poor internet connection are joined by OMAFRA’s Albert Tenuta and University of Guelph-Ridgetown Campus’ Dave Hooker.

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

SUMMARY

  • Crops could be exceptional, where Dave is (except for slug damage on his own farm). Albert is talking inoculating for corn leaf blight
  • Seeing flooded fields is a little hard to take
  • Graphics! Photos!
  • Clip #1: Corn School: Tackling tar spot in Ontario
  • Getting excited about lesion shapes, only something a pathologist would do
  • What percentage of Ontario corn could be affected by tar spot, vs. other diseases? Northern corn leaf blight, grey leaf spot, gibberella ear rot, etc are still a concern!
  • Local movement of tar spot between fields, maybe a kilometre or two
  • Infection timeframe? (Check out the graphic with the symptoms to look for) It takes four weeks or so to ramp up and gain inoculum load.
  • With recent storms coming across this early in the season, is the U.S. far enough ahead for tar spot spore movement?
  • Polycyclic snowball effect
  • Starter fertilizer going on heavily? What extra management should be employed to help the corn crop along?
  • Remember the host/environment/pathogen triangle
  • Feeding students questionable things… huitlacoche
  • Clip #2: Soybean School: Fungicide applications and tank mixing strategies
  • Why is it so important, if you’re in a white mould situation, that you head into that crop and look early?
  • It’s not just weather that drives disease, look at all of the risk factors present
  • Canopy! How dense is it? For white mould, that’s a top risk factor
  • Sclerotia can live anywheres up to 8 years, depending on where they exist in the soil profile
  • Genetic resistance to diseases, and on the flip-side susceptibility
  • Fungicides will only make a bad situation less bad, under certain expectations. Use other tools too
  • There’s a fine line between having 20 to 30 per cent white mould in a field, and then environment kicks in and bam you’ve got 60 per cent
  • The fields that are planted to a more susceptible variety may respond better to fungicides…
  • Sharpening pencils at both ends
  • Does a cereal rye mat reduce white mould risk in soybeans? A barrier for spore spread. Risk for white mould is lower in no-till
  • Clip #3: Corn School: Managing a variable crop for gibberella control
  • Western bean cutworm feeding or infection through the silk channel. Even hail damage can be an infection point for gibberella, which can cause…
  • DON, DON DON DON, DON DON DON DON DOOOOOON
  • Fungicide timing to reduce levels of mycotoxins
  • If you have a lot of ground to cover, it’s not a very wide spray window, how do you make a game plan? High mycotoxins. What was learned from 2018?
  • Northern corn leaf blight control. 50 to 60 bushel loss on a susceptible variety. Just by having fungicides and using a stronger variety, only a 15 bushel loss
  • Why spray pre- or at VT/R1? Management of acres is a factor. What about waiting till gib or ear-rot timing? Can control for other leaf diseases, see if there’s western bean cutworm. There can be a lot of acres to spray though…
  • Sometimes herbicide/fungicide/insecticide just won’t coincide! But never say never

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