Wheat Pete's Word, July 14: Purple stems, burnt up wheat, tasseling corn, and aphids at threshold


What’s the weirdest colour you’ve ever seen a crop turn?

This week in Ontario, at least one farmer is reporting very dark straw where the wheat crop was touched by frost in late May. An agronomist also reports purple stems in another area. What the heck is happening here?

Never fear, as Peter “Wheat Pete” Johnson is here with this week’s Word, and he’ll explain what the heck is happening to wheat stems, plus offer up not one but two crop alerts: one for soybean aphids, and the other for white mould.

Have a question you’d like Johnson to address or some yield results to send in? Disagree with something he’s said? Leave him a message at 1-888-746-3311, send him a tweet (@wheatpete), or email him at [email protected].


  • Smack upside the head time! Carbon penalty is the wrong term. Residue management!
  • Jess from New Zealand, thank you for reaching out and using Wheat Pete’s 15
  • Cover crops in New Zealand? Whoa!
  • It is WET in Ontario. Drought or dry no more. We’re on to deluge.
  • “Dry weather will scare you to death, but wet weather will starve you to death”
  • Waist high by the middle of July soybeans — but too much vegetation and growth can be all bad if there’s too much moisture. Check out this piece on root rots and edible beans.
  • Three hours of drizzle and constant rains means oh man, it’s tough to get wheat out of the field
  • Two weeks before and two weeks after tassel are the most important times for sunshine in the corn crop
  • Night time temps have been solid for corn, but it’s been dreary. Send the sun!
  • Drumheller, Alta., the drought is extreme in Western Canada. One inch of rain total since seeding. 35+ degrees C for an entire week. The wheat crop pollinated, is there hope? There IS because the flag leaf is still green and the head is green. It’ll be low yield, but rain can still add yield in the grain fill period.
  • Cold or frost at heading had a wild impact. In the frosted areas 65 bu/ac with dark straw (extra photosynthate) vs 110 bu/ac average. Yield monitor hit 130 to 140 bu/ac in the good spots
  • Purple stems happen when grain fill is done but there’s still energy being moved up with nowhere to go

  • 1.5 kernels/floret vs 2 or 3 in some areas hit by frost
  • Lake effect? 10 days earlier than normal. Early wheat usually means lower yields for Ontario.
  • But does early wheat mean double crop beans? It could, and could make up the difference
  • 330 falling number (must be over 250 seconds for millers to make any use of it). 68 pound per bushel test weight in Niagara region. Went to 247 falling number because of a weekend of rain. Ouch.
  • What is falling number? Watch this video!
  • Blending it off doesn’t work, please don’t do this. You’ll ruin the wheat.
  • Corn is in short supply for feed… switch to wheat?
  • Plot results: early wheat makes grain, remember. Fungicide plot: Miravis Ace offered up a 8 bu/ac return.
  • ALERT! ALERT! ALERT! Soybean aphid numbers are exploding in some areas. If you have threshold numbers you MIGHT have to spray twice, largely because of the impact of the spray on beneficials. There is a new product, Sefina, that is less harmful on beneficials that might be a good option
  • White mould risk is incredibly high this year. If this rain and humidity keeps up, get the sprayer rolling. Edible beans, too!
  • Too good of growth might mean two white mould fungicide products
  • Use Sporecaster for soybeans, but for edibles it takes more interpretation

Wake up with RealAgriculture

Subscribe to our daily newsletters to keep you up-to-date with our latest coverage every morning.

Wake up with RealAgriculture

Other Episodes

Wheat Pete's Word (view all)Season 7 (2021) Episode 24

Please register to read and comment.

Privacy Preference Center


Necessary cookies help make a website usable by enabling basic functions like page navigation and access to secure areas of the website. The website cannot function properly without these cookies.

gdpr, __cfduid, PHPSESSID, wordpress_test_cookie, woocommerce_items_in_cart, woocommerce_cart_hash, wp_woocommerce_session, wordpress_logged_in, wordpress_sec, wp-settings, wp-settings-time, __cf_mob_redir, wordpress_cache, realag


Measuring interactions with the ads on the domain.



These are used to track user interaction and detect potential problems. These help us improve our services by providing analytical data on how users use this site.



Preference cookies enable the website to remember information that changes the way the website behaves or looks, like your preferred language or the region that you are in.

chartdefaults, comment_author, comment_author_email, comment_author_url
JSESSIONID, _os_session,anonymous_votes,csrf-param,csrf-token,user,user-id,user-platform,intercom-session,intercom-lou,intercom-session
personalization_id, tfw_exp


Register for a RealAgriculture account to manage your Shortcut menu instead of the default.