By Bernard Zandstra
The new Matrix label is good through March 31, 2020, to help control several annual grasses and broadleaves on blueberries, raspberries and blackberries.
The U.S. Environmental Protection Agency (EPA) has approved a Section 3 Supplemental Label for use of the herbicide Matrix SG 25 percent WDG (rimsulfuron) for use on blueberries, raspberries and blackberries. This label had been in effect previously and had expired in 2017. The new label was approved March 16, 2017, and will be in effect through March 31, 2020.
Matrix may be applied to these crops at 4 ounces product per acre (0.063 pound active ingredient). It may be applied pre-emergence or early post-emergence to the weeds. If weeds are present at application, add non-ionic surfactant at 0.25 percent to the tank mix. Matrix is most effective if moved into the soil (activated) by 0.5 inch rainfall. This normally is not a problem in spring in Michigan.
On highbush blueberries, apply Matrix to bushes established at least one year. Apply in a strip on each side of the row, avoiding contact with green blueberry leaves or stems. Matrix is moderately soluble and should not be used on soils classified as sands to avoid leaching into the bush root zone. Do not exceed 4 ounces product per acre per year. If Matrix is applied in a band of 50 percent or less of the total area, a second application may be made each year. Matrix may be applied up to 21 days before harvest.
On caneberries, apply Matrix before new canes emerge in spring or after canes are 3 feet tall. Direct the spray to the bottom 12 inches of the canes. If Matrix is applied to emerged caneberry plants, severe stunting or death may occur. Do not use Matrix on very light sands or saturated soils. There is a 21 day pre-harvest interval.
Matrix herbicide is active against several annual grasses and broadleaves, including mustards and pigweeds. It has fair activity against most of the composites, but is weak on common groundsel. It is also weak on common lambsquarters and eastern black nightshade. It will provide six to eight weeks of weed suppression at the labeled rate, and is most effective if used with other residual herbicides.
Matrix is a group 2(B) ALS inhibitor; Sandea is the only other group 2 herbicide labeled and widely used in fruit crops. Matrix is a good tank-mix partner with the PS II inhibitors such as Karmex, Group 7(C2), or Princep, Group 5(C1), and the PPO inhibitors such as Chateau or Zeus, Group 14. Michigan State University Extension reminds growers to watch for any crop chlorosis or stunting, and adjust practices for the next year.
Other commercial rimsulfuron herbicides may include these crops on the label. For instance, Solida from FMC includes blueberry and caneberry on the label.