Five Steps for Proactive Orchard Weed Control
Unrelenting drought conditions and dwindling irrigation supplies continue to challenge California stone fruit growers. Adding to the concern, a recent study documented how California’s declining winter tule fog is threatening fruit and nut production.
While weather is beyond grower control, weeds, another perennial orchard stressor, can be handled with the right orchard weed control program.
Staying ahead of weed populations is key to achieving good control, says Kurt Hembree, weed management farm advisor, University of California Cooperative Extension, Fresno County. “Take steps to keep weeds from gaining a foothold,” he says, “and don’t rely on the same program year after year.”
Hembree offered five tips for successful orchard weed control that starts in the fall and carries over into season-long control.
1. Review Treatment History
“Fall is a good time to review past weed-control efforts, including successes and failures,” Hembree notes. He advocates learning from the past to adjust programs for improved control.
2. Clean Up Berm Areas
After harvest, remove leaves and other trash from berms with a blower. “Cleaning up the berm area before applying preemergence herbicides will improve herbicide-soil contact and maximize treatments. This clean-up step makes pre- and postemergence treatments much more effective.”
3. Time Preemergence Applications With Predicted Rain
“It’s advantageous to time your application with one of fall’s first storms to get the most benefit from treatment,” Hembree notes. “Just a quarter of an inch of moisture is enough to activate herbicides.”
4. Monitor for Weed Escapes
After a fall pre- or postemergence herbicide application, monitor the orchard for weed escapes and treat flushes immediately. “Under dry conditions, some growers may think it’s OK to wait a month or two before treating escapes, but droughty weeds can quickly become less susceptible to herbicides,” he explains.
5. Manage Resistance
“Rotating active ingredients and tank-mixing products with different modes of action is crucial to make certain herbicides remain effective for a long period of time,” Hembree says. “Another big part of managing resistance is treating escaped weeds while they’re small and easy to control.”
Match Treatment to Weed Spectrum
For optimal orchard weed control, growers and consultants need to understand an orchard’s weed challenges and use a herbicide mix that will control the weed spectrum, notes Hembree.
“Tank mixes might include products with residual control, such as DuPont™ Matrix® SG herbicide, Alion, Surflan, Prowl or Chateau herbicides, which include different modes of action to help manage resistance,” Hembree notes. “And if we’re dealing with emerged weeds, we can also include a burndown herbicide.
“Effective residual weed-control programs provide good return on grower investment. Avoiding a follow-up treatment will save $15 to $20 per acre,” Hembree adds. “Making smart choices in weed control is the important thing. If cost alone is guiding your decision, you’ll be fighting a losing battle with weeds.”
Flexible Control of Difficult Weeds
Matrix® SG herbicide offers preemergence and early postemergence control of difficult weeds, including fleabane and marestail. The low use rate of 4.0 ounces per acre and flexible application options make Matrix® SG an ideal fit for most grower programs.
Scott Chase, retail account manager, East Fresno County and Northern and Eastern Tulare County, DuPont Crop Protection, offers the following application options with Matrix® SG:
1. A single broadcast application in fall or early winter, or
2. A single banded application in the fall (50 percent band or less) supplemented with micro-sprinkler chemigation treatment in the spring or summer, or
3. Banded sequential applications in the fall and spring (50 percent band or less) to help extend preemergence weed control into summer.
For a complete list of weeds controlled by Matrix® SG and application recommendations,
refer to the product label.
The information provided on this website is for reference only. Always refer to the product labels for complete details and directions for use.