New herbicide registration: Matrix for small fruit crops

Matrix labeled for blueberries and caneberries (raspberries and blackberries).

EPA has approved a label for Matrix (rimsulfuron) herbicide for use in blueberries and caneberries (raspberries and blackberries). The label is a supplemental label to the Section 3 federal label, and will be incorporated into the main label whenever it is revised.

Matrix is a sulfonylurea herbicide that is an ALS inhibitor. The only other ALS inhibitor currently labeled for fruit plantings is Sandea (halosulfuron). ALS inhibitor herbicides are active at very low rates and thus are subject to development of weed resistance. Therefore, these herbicides should not both be used in the same year.

Matrix may be applied to blueberries established in the field for at least one year. It should be applied preemergence or early post-emergence in a band on both sides of the row. The normal use rate is 4 oz of product (0.063 lb ai) per treated acre.

Matrix has good preemergence and postemergence activity on most annual broadleaves and grasses. It is weak on common lambsquarters and eastern black nightshade. It should not be applied to blueberries on soil classified as sand. There is a 21-day preharvest interval (PHI).

For raspberries and blackberries, Matrix may be applied to plants established at least one year. For mowed raspberries, it should be applied in early spring before any new growth emerges. Application over the row after new growth has emerged may result in crop stunting. For non-mowed raspberries, it should be applied in a band on each side of the row. It also may be applied later as a directed spray to control emerged weeds and to extend preemergence weed control. It should not be used on light, sandy soil. The PHI is 21 days.

Matrix should be used in rotation with other herbicides. Karmex (diuron), Princep (simazine), and Sinbar (terbacil) are good rotational herbicides with broad weed control spectrums. Tank-mixes with Surflan will improve annual grass control and tank-mixes with Dual Magnum will improve eastern black nightshade and yellow nutsedge control.

Callisto (mesotrione) and Chateau (flumioxazin) may be included in a herbicide rotation on blueberries. Casoron (dichlobenil) and Solicam (norflurazon) may be used on blueberries and caneberries. Use of several different herbicides in rotation will improve overall weed control and avoid buildup of resistant or tolerant weeds that often infest blueberries and raspberries.

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