Reducing Weeds in Berry Crops, part 1


Berry growers have many pest challenges growing their crops, and weeds are often at the top of the list. Whether you are producing berries organically, on plasticulture or conventionally, there are many things you can do to reduce weeds in your crop. Many of my comments will refer to strawberries but some of these ideas will also apply to raspberries, blueberries and other bush berries.

If we had the perfect herbicide - one application each spring, controlling the whole spectrum of weeds for the entire season, with no crop injury and no risk to the environment - we wouldn't even be talking about this. But we know that each of the herbicides we use has its limitations, and each treatment can fill one niche of our weed management program. Even the newer reduced risk herbicides in development do not offer the prospect of perfect weed control in berries - so we need to focus on an integrated weed management program - and an important aspect of IWM is reducing weeds in your fields.

In this column, I'd like to focus on what to do before you plant your next berry field - to reduce weed problems:

  1. Site selection: Every grower knows which field has the lowest weed pressure. This is important for annual weeds like pigweed and lamb's-quarters, but especially important for perennial weeds like nut sedge, ox-eye daisy, and toadflax, where we don't have good herbicide options. Some farms are limited by soil type in where they can rotate berries, or prefer using well-placed fields for retail or PYO visibility. If you have to return to fields with high weed pressure, it is important to focus efforts on cleaning up weeds before you plant.
  2. Crop rotation: The longer I'm in this business, the more respect I have for the benefits that can be achieved by a well-planned rotation, especially when planting perennial crops like berries. Berry growers have used long rotations to reduce disease, nematodes or insects, but a good rotation can also reduce weed pressure. Growing field corn can give you many options of effective herbicides to reduce weed populations in general. Including a winter cereal can break the life cycle of many weeds, and also gives you the option of an inexpensive treatment like 2,4-D or Buctril to clean up broadleaf weeds like thistles or dandelions. Growing Roundup Ready crops like soybeans can reduce annual weed pressure from pigweed, lamb's-quarters and annual grasses, especially if 2 applications are used. And some cover crops can be used to suppress weeds in general. Ensure that herbicide residues from previous crops will not harm berries though
  3. Preplant cleanup: The year before planting berries should be focused on all opportunities to reduce weeds. A spring burndown with glyphosate is a good start. Weed scouting, spot treatments, and effective herbicides are very important in the preplant year. In the fall, glyphosate, amitrole or 2,4-D applications can effectively reduce many perennials or winter annuals.

In the next issue, I will focus on things you can do at planting time to reduce weeds.

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