What Can I Do to Improve Weed Control in My Orchard?
Weeds reduce tree growth, fruit size, yield, and cause inefficient utilization of irrigation water. Below are several suggestions you might want to consider for improving weed control.
Tank Mixing PRE (preemergence) Herbicides:
We know that the combination of two herbicides broaden weed control spectrum and extends residual control. Unfortunately the improved control does not come without increased expense. However, improved control can eliminate the need for at least one postemergence herbicide application. A specific example is the improvement of preemergence grass control when Solicam is tank mixed with Simazine.
Rotating Herbicide Programs
Finding an effective and economical herbicide program is difficult. When one is found it may be used year after year. However, this practice can lead to the demise of the herbicide program of choice. Continued use of the same program selects for weed species that are poorly controlled by the herbicide or herbicide combination. Finding two of three herbicide combinations and rotating them will sustain the herbicide program of choice. For example, if Karmex at 3 lbs/acre is your preferred preemergence herbicide you may want to rotate that with Simazine at 2 qt/A plus Solicam at 2.5 lb/A.
Delay PRE Herbicide Application
One way to extend PRE weed control into the summer is to delay the application of a spring PRE herbicide. A fall PRE herbicide can delay the need for a spring PRE herbicide until late May. If you do not use a fall PRE herbicide you should consider using a "delayed PRE" application program. This programs consists of a mid to late March application of a non-selective herbicide like Roundup UltraMax or Touchdown. This application will generally provide control through early May. When emerging summer annual weeds get 2 to 4" tall apply a non-selective herbicide in combination with the