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Fall Weed Control




~The use of residual herbicides are the best choice for fall treatment~

The cool crisp morning air is a signal to start thinking about your fall spray plan. It is an excellent and highly effective time to control most perennial and biennial weeds. Fall rains and cooler temperatures bring on a flush of re-growth and germinate a whole new batch of weed seedlings, thus providing good conditions for extending the herbicide application season.
For good control, its critical to target weeds at their most vulnerable stage, so its very important to make herbicide applications at the right time of year. The best time to control perennial broadleaf weeds is when they area actively growing in spring, and in the fall when the weeds are storing sugar back into the roots as a reserve for re-growth in the spring. Cooler weather and shorter days in the fall initiate this response. So when its bonfires and football season, start thinking about how you are going to control your noxious weeds.
When herbicides are applied at this time, the chemicals are transported to the roots along with the carbohydrates, killing the entire plant instead of just the parts above the soil surface. This is especially important for hard-to-kill and spreading broadleaf weeds like Canada thistle,
St. johnswort and Rush skeletonweed, which have underground creeping roots called rhizomes or extensive root zones.

If the timing of the application is correct, the plant will take in the herbicide. It will move through the plant, and you will have an effective application. Just like with early spring treatments, these lush young plants are relatively easy to control, which means the lower labeled rate of herbicide will get the job done on most species, which translates to more money in your wallet.

Residual herbicides control through the fall and into the following spring. Herbicides such as Milestone, Telar or Perspective, are slower acting, therefore will get to the roots and control the whole plant, and will provide pre-emergence control of germinating seeds, giving your pastures a head start come spring.

Be sure to spray several feet outside the perimeter of a weed patch, to get the plants that may be there that you can not see yet, or seed banks waiting to germinate. This is where the residual control of Milestone, Telar, or Perspective, especially come into play. An advantage of Milestone is that it can be purchased without a pesticide license, and can be applied to seasonably dry wetlands and up to the waters edge.

Contact herbicides such as, Weedar 64 or Hardball, need to be applied to growing plant leaves in order to work. Over-spray onto the soil surface renders them useless. When applied to growing plant leaves, they are as effective as residual herbicides, except they do not have any residual activity in the soil to help control plants.

As always, be sure to use a surfactant.

Read and follow all directions on labels and use personal protective equipment.

When should fall applications be made?

  • Once fall moisture has stimulated a new flush of seedlings.
  • After a light frost, but before a heavy freeze.
  • The window of application closes after a killing frost.
  • Applications can be made up to late October or early November before soil freezes.

Get to the Roots

Tough to control perennials are more vulnerable in the young stage. As they prepare for dormancy, they transfer nutrients from their leaves to their root systems, helping move fall-applied herbicide deep into the roots for a more complete control. Delaying treatment until after the first frost, but before a hard freeze (visible leaf damage) – will help make the herbicide treatment more effective, keep working through spring, stopping new weed sprouts and giving forage grasses an extra advantage. Fall control helps ensure a speedy recovery and prepares grasses for winter. Plus, fall-treating weeds before they gain a foothold is more cost-effective.