Strawberry and Raspberry Pest Management in Wisconsin

Raspberry Weed Management
Effective weed management in raspberries combines cultivation,
mulches, and herbicides. Weed management is essential to reduce
competition for water, nutrients, and light during the development of
the crop. Weeds can also harbor diseases and insect pests and can
interfere with cultural practices and harvesting.
Eliminate perennial weeds such as quackgrass, thistles, and dock the
year before planting by using smother crops; summer fallow; nonresidual,
systemic herbicides; and cultivated agronomic row crops.
Not all weeds that occur in raspberry plantings in Wisconsin are
controllable with herbicides. Additionally, repeated use of the same
herbicide on the same field growing the same crop may lead to weed
resistance. In these cases mechanical means such as cultivation, pulling,
and hand hoeing are necessary. Mulches can also control annual
weeds. Both organic mulches, such as straw, leaves, sawdust, or wood
chips, and synthetic mulches, such as polyethylene, minimize weed
problems and conserve soil moisture. Young raspberry fields
established with organic mulches typically produce significantly more
canes than unmulched fields. After the establishment year, mulches
may be less beneficial for plants due to rodent problems, higher
disease incidence, and shallow rooting.
You can control weed growth between the rows by planting sod such
as Kentucky bluegrass, perennial rye, or red fescue at the time of
planting. Sod prevents many weeds from growing, and occasional
mowing slows the growth of other weeds. It also reduces dust and soil
compaction, improves field access after rain or irrigation, and. helps
maintain soil structure and organic matter levels.
After planting, shallow cultivation in the plant rows can help reduce
weed problems. Cultivation also serves to keep the rows narrow and to
eliminate excess canes. To reduce the potential for root damage, don’t
cultivate deeper than 2–3 inches. In established plantings, cultivation
should stop before harvest to avoid knocking fruit off the canes.
HERBICIDE USE Chemical weed control in established plantings is of most value in
reducing weed populations in the planting row. Growers using an
herbicide for the first time should limit the treated area until they are
familiar with the herbicide’s effectiveness and crop safety. Sprayers
should be calibrated at least each year.
Young tissue-cultured plants are much more susceptible to herbicide
damage than traditional dormant cane stock. Ideally, avoid using
herbicides on these plants before fall of the establishment year or use
the lowest labeled rates on new plants.
If you are applying herbicides only to the planting row, be sure to
calculate the actual area being sprayed and not the entire planting
area. Otherwise you will overapply, leading to plant injury or death.
Before using a herbicide, read and follow the label directions! Use only
registered materials. Table 10 lists herbicides registered for use on
raspberries in Wisconsin. Products are listed alphabetically and
represent treatment options for each period covered. Inclusion of
product names is not an endorsement of a manufacturer’s brand.
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