August 2022 Forage Report

Ontario Hay Listings is a free classifieds service provided by the Ontario Forage Council. Producers looking to buy or sell hay or straw are encouraged to post an ad.

Bt-resistant Corn Rootworm

Corn rootworm is a serious pest of continuous corn. Root feeding reduces yield and increases the risk of lodging and “goose-necking” which can make harvest difficult or impossible. Silk feeding can reduce kernel development. For 16 years, producers growing corn-on-corn have relied on hybrids with rootworm Bt traits (Bt-RW), sometimes called “below-ground protection”, to minimize crop damage. Since 2019, populations of corn rootworm with resistance to Bt-RW have been identified in Ontario. Crop rotation is the most effective and least expensive way to manage corn rootworm:

  • For dairy, beef, and sheep farms, an alfalfa-corn rotation is simplest. The corn hybrid should not have a Bt-RW trait.
  • Where rotation is challenging, a four-year rotation can be used:
    • Year 1: no Bt-RW trait. Scout for adult beetles in August/September.
    • Year 2: no Bt-RW trait. Soil-applied insecticide may be used if Year 1 adult population is above threshold.
    • Year 3: Bt-RW trait, no insecticide.
    • Year 4: rotate out of corn. This could be a winter cereal/sorghum-sudangrass double crop for silage, or a legume crop.

If producers do not implement good corn rootworm management practices, within a few years the Bt-RW traits will no longer work at all. Crop losses in corn-on-corn fields could make corn uneconomical to grow for feed, particularly silage and high moisture corn. Producers are encouraged to work with both their agronomist/crop inputs supplier and nutritionist/feed rep to come up with a crop plan to manage corn rootworm while meeting feed needs.

Agricorp Deadlines

  • October 1st: apply/change summer- or fall-seeded New Forage Seeding production insurance
  • November 8th: report acreage for summer- or fall-seeded New Forage Seeding
  • November 22nd: pay premium for summer- or fall-seeded New Forage Seeding
map showing difference from normal precipitation
Figure 1. Percent of average precipitation received across Ontario in August 2022

South and West

  • According to AAFC, Niagara, Hamilton, Brant, and part of Norfolk received below-average precipitation for August. The rest of the region received average or above-average rainfall.
  • The southern-most counties will be entering the fall rest period for alfalfa in early September. See Figure 2 for average start dates.
  • Six of the 10 high-risk counties for Bt-resistant corn rootworm are in this region.
map depicting the start of the alfalfa fall rest period across Ontario
Figure 2. Average start dates for alfalfa’s fall rest period

Central and East

  • According to AAFC, most of the region had above-average rainfall for the month. Parts of Ottawa, Lanark, and Renfrew received over twice as much rain as normal. Pockets in Durham and Peterborough had less precipitation than normal.
  • Four of the 10 high-risk counties for Bt-resistant corn rootworm are in this region.


  • According to AAFC, the eastern part of Algoma and a pocket in Sudbury had below-average precipitation. The rest of the region had average or above-average rainfall for August.


  • According to AAFC, Thunder Bay had below-average precipitation. Rainy River and Kenora had average rainfall for August.

Pasture Production

Four pasture sites across Ontario are participating in a precision agriculture project to use grass more efficiently. Each week grass growth rates, among other production metrics, are measured using a rising plate meter. Average daily grass growth rates are shared publicly, while more detailed information is available to participating pasture managers.

Year-to-date grass growth rates are shown in Figure 3.

Figure 3. Year-to-date grass growth rates at project sites across Ontario.

Many thanks to Living Lab – Ontario, Ontario Beef Research Centre – Elora, Victoria County Community Pasture, and la Ferme d’éducation et de recherche du Campus d’Alfred (FERCA) for their involvement in this project.