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Tree Fruit Herbicide
 Recommendations
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Herbicidesapplied in late October or early November
control winter annuals, certain perennials, and early
season summer annuals. Spring herbicide applications
extend summer annual weed control through harvest.
Advantages of two herbicide applications per year include:
1. Control of winter annual weeds, including
camphorweed, wild lettuce and horseweed
(marestail) and summer annual weed control for
the same cost as most single application weed
control programs.
2. Improved spring labor and equipment distribution
requirements by controlling early summer annual
weeds with residual herbicides applied the
previous fall, thus delaying the need to spray in
the spring until May or early June.
3. Increased consistency of weed control treatments,
especially control of summer annual weeds when
dry weather follows the spring herbicide
application.
4. Decreased risk of crop injury, since each herbicide
application must last less than a full year.
Herbicides can be alternated and rates can be
reduced or split to improve crop safety.
5. Decreased competition from established winter
annual weeds and summer annual weed seedlings
in March, April, and May for fertilizer and water
when the trees begin to grow.
Late Fall Herbicide Applications should include a
translocated postemergence herbicide and a residual
broadleaf herbicide. Apply 2,4-D to control emerged
winter annual broadleaf weeds tank-mixed with Princep for
residual control. Consider Roundup 4SC if perennial
weeds are present and treatment is recommended in the
fall. Add Princep for residual control of broadleaf weeds.
The use of a grass herbicide in the fall depends on the
product chosen. Kerb 50WP is the only grass herbicide
that mustbe applied in the fall, if it is used, to control
cool season perennial grasses. An additional residual
annual grass herbicide is needed in the spring to provide
full season summer annual grass control following a fall
application of Kerb 50WP.
Solicam 90DF, Surflan 80WP, Devrinol 50WP and
Prowl 4EC are annual grass herbicides that should be
applied in late fall or as a split application, half in the fall
and the second half in the spring. Use the split
application when grass pressure is heavy for best results.
The use of these herbicides in spring only has resulted in
inconsistent weed control when dry weather followed the
application.
Sinbar 80WP applications for annual grass control
should be applied only in late spring. The relatively high
solubility of Sinbar 80WP results in leaching when
applied in the fall. Increased risk of crop injury and poor
weed control can result.
Followup Late Spring Applications should include
a different residual broadleaf weed herbicide and a residual
grass herbicide. Add a postemergence herbicide only if
needed. Use Karmex 80WP for residual broadleaf weed
control. Apply Sinbar 80WP or the second half of a split
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A good orchard floor management program eliminates
and prevents the reestablishment of undesirable
vegetation. Weeds compete with fruit trees for water,
nutrients, and light; serve as alternate hosts for diseases
and harmful insects; harbor rodents; and impede harvest.
Herbicides used to control weeds must have a good
margin of crop safety to minimize the risk to the tree.
Choose herbicides for use in the tree row that are
labeled, have adequate crop safety (Table 17), and control
the weed species in your orchard (Table 18). Use the
correct amount of residual herbicides for each soil type
(Table 19). The use of a single herbicide repeatedly will
lead to an increase in resistant weeds or weed species. The
use of herbicide combinations, herbicide rotations, and
sequential or spot treatments in a well-managed weed
control program will eliminate or minimize problems.
The recommended herbicides have been evaluated for crop
safety and effectiveness. Information, on dwarf trees and
trees growing on their own roots, is incomplete. Use
herbicides with care on these trees.
Weeds can be classified by their life cycle. Annual
weeds live less than one year. Summer annuals germinate
in the spring or early summer, grow, flower, produce
seed, and die in the fall. Winter annuals germinate in late
summer or in the fall, grow vegetatively through the fall,
overwinter, flower, produce seed, and die in the spring.
Biennial weeds live more than one year but less than two
years, produce seed, and die. Perennial weeds live more
than two years. They often reproduce vegetatively, as well
as by seed, and are much more difficult to control.
Consider summer annuals, winter annuals and biennials,
and perennial weeds separately when planning a control
program.
Weed control in a newly planted orchard should be
planned to provide a maximum margin of crop safety.
Tillage and/or herbicides prior to planting should control
established biennial and perennialweeds. Apply a
combination of herbicides to control annual grasses and
broadleaf weeds. Apply in early spring after 1 to 2 inches
of rainfall or irrigation has settled the soil around the roots
of the newly planted trees, but before weeds emerge or tree
buds break.
Apply herbicides to the tree row in established
orchards twice annually, in late fall and in late spring.
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