Blueberry only; Oregon and Washington
Rate 2.66 to 5.33 fl oz/a (0.063 to 0.125 lb ae clopyralid/a) depending on weed species present. Make a maximum of two applications with total usage not to exceed 10.6 fl oz/a or 2/3 pints/a per season.
Time Up to 30 days before harvest, or after last harvest.
Remarks Blueberry plants are most sensitive to Stinger when applied in the spring, during the crop's annual flush of growth and prior to bloom. Blueberries are less sensitive after bloom has ended. Canada thistle, clover, and weeds of the Asteraceae family (dandelion, sowthistle) are controlled. Directed Spray Treatment: Apply Stinger uniformly as a spray at 2.67 to 5.3 fl oz/a directed to the soil, and away from the blueberry plants to the row middle without contacting the foliage or woody portions of blueberry plants. Apply with ground broadcast equipment, backpack sprayer, or wipe applicator in a total spray volume of a minimum of 10 gal/a. Spot Treatment: Hand-held sprayers may be used for spot applications, but care should be taken to apply Stinger at the proper rate per unit area. Do not concentrate the herbicide on the soil. Wipe Treatments: For wipe treatments, apply 2% solution of Stinger in water (2.5 fl oz or 75 mL/gal).
Caution Consult SLN labels OR-100011 and WA-100005 before applying to become familiar with situations that will increase the chance of injury to blueberries. Do not permit Stinger to contact desirable foliage because crop injury will result. Apply spray uniformly over the area to be treated, rather than concentrating the spray onto targeted weeds. Do not apply Stinger during the time from one week prior to bloom until one week after bloom. After bloom, apply Stinger up until 30 days prior to harvest. Do not apply within 30 days of harvest.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
Rate For plants 1 to 4 years old: 0.023 to 0.031 lb ai/a (0.5 to 0.67 oz/a Sandea); for plants 4 years or older: 0.023 to 0.047 lb ai/a (0.5 to 1 oz/a Sandea)
Time Preemergence or postemergence (nutsedge control)
Remarks For nutsedge control, make a single postemergence application of 0.75 oz/a minimum to nutsedge that has 3 to 5 leaves. Two applications are permissible if additional nutsedge plants emerge, but allow 45 days between applications. Do not irrigate for 3 to 4 days after application to maximize efficacy. Add a nonionic surfactant to improve activity. Preharvest interval is 14 days. Sandea also can be applied preemergence to control annual weeds including marestail and common groundsel. Preemergence control of nutsedge is poor. Do not apply to 'Elliott' variety bushes established less than four years.
Caution Do not let spray contact blueberry bushes. Do not apply more than 2 oz/a per year. Do not apply to plants less than 1 year old, or concentrate the spray in the crop row.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
Blueberry and currant only
Rate 0.094 to 0.188 ai/a (3 to 6 fl oz/a Callisto)
Time Prebloom, post-directed spray.
Remarks May be applied as a split application (3 fl oz/a each), but no more than 6 fl oz/a per year. Use crop oil concentrate at 1% v/v to enhance weed control. Separate applications by 14 days. Has both burndown and soil-residual activity. Controls many broadleaf weeds, but controls few grasses and no perennial weeds.
Caution Applying after the onset of bloom may result in illegal residues.
Site of action Group 27: inhibits 4-hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Triketone
rimsulfuron (Matrix SG)
Blueberry only in Oregon and Washington
Rate 0.0625 lb ai/a (4 oz/a Matrix SG)
Time Apply in spring or fall, preemergence or early postemergence, to actively growing weeds.
Remarks Use a directed spray application and minimize spray contact with blueberry plants. Use only in berries that have gone through one growing season, and are in good health. Preharvest interval is 21 days. Use adjuvants for improved postemergence control.
Caution Do not exceed one application per year. When applied as a banded treatment (50% band or less), Matrix SG may be applied twice per year.
Site of action Group 2: Acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea