Things to consider when using Sencor herbicide on potatoes

Sencor^® is a proven broad-spectrum herbicide registered for broadleaf and grassy weed control in potatoes and a wide range of other crops.

Active ingredient:

Metribuzin (Group 5)

Formulations:

• Sencor^® 75 DF - Water Dispersible Granular (75% dry flowable)
• Sencor^® 480 F – Suspension (480 g/L)

Packaging:

• Sencor^® 75 DF is available in 2.5 kg jugs
• Sencor 480 F is available in 5 L jugs

BC, AB, SK, MB

• Each 2.5 kg jug treats 6.7 to 17.9 ha (16.5 to 44 ac.)

ON, QC, NB, NS, NFLD, PEI

• Each 2.5 kg jug treats 1.7 to 4.5 ha (4 to 11 ac.)
• Each 5 L jug treats 2.2 to 5.9 ha (5.5 to 14.5 ac.)

Rainfastness:

6 hours after application

Pre-Harvest Interval:

60 days

Features and Benefits

• Broad-spectrum broadleaf and grass weed control
• Provides early weed control during critical crop stages
• Can be applied pre-emergent or post-emergent
• Excellent crop safety
• Rate flexibility (depending on stage, formulation and tank mix partner)

Application Tips and Best Management Practices for Potatoes

Pre-emerge Considerations

• Must be used with irrigation in Prairie Provinces.
• Allow hill to settle prior to application as any soil disturbance after application can result in weed escapes.
• Dry/drought conditions can result in reduced weed control.
• Needs to be activated before broadleaf weeds reach 4 leaf stage and grasses reach 2 leaf stage.
• Sencor binds to clay, therefore, higher rates are required in heavier soils for longer residual weed control.
• Sencor binds to OM. Higher rates are required in higher OM soils, >4%. This also impacts the longer persistence of carryover when considering sensitive subsequent crops. Sencor breaks down faster in soils with higher pH. Low pH soils are at a higher risk for persistence.
• Do not tank-mix Sencor with 2,4-D.

Post Emergent Considerations

• Detoxification of Sencor is more concentrated in sunlight.
• For best weed control and crop safety it is best to spray mid-day in full sunlight with sunny conditions prior to and the day after application.
• Use high water volumes; 18-20 gallons of water/acre is recommended.
• Higher water volumes can be used as long as you don’t experience run off.
• Tank-mixing with rimsulfuron will antagonize rimsulfuron grassy weed control.
• Under dry and sunny conditions rainfast is 6 hours. Under cloudy conditions allow for 12 hours for rain fastness.
• Temporary yellowing or leaf burn may occur if crop is under stress from poor growing conditions such as periods of cool, wet, and cloudy weather. Avoid post-emergence application under these conditions.

Crop Tolerance

• Some potato varieties can be sensitive to Sencor applied post-emergence.
• Symptoms may appear such as yellowing/necrosis of leaf veins or leaf margins, stunting, and possible delay in harvest.
• Varietal tolerance can vary and is affected by rate and conditions at application.
• Apply Sencor in a small test area to ensure risk or level of potential injury is acceptable to the grower prior to adoption as a general field practice. Sensitivity to or injury after a post-emergent application of Sencor is typically visible in the test area within 5 days after application.

Crop Rotation Considerations:

• Rotation crops such as onions, celery, peppers, cole crops, lettuce, spinach, sugar beets, table beets, turnips, pumpkin, squash, cucumbers, melons, tobacco and non-triazine tolerant canola (rapeseed) are sensitive to Sencor herbicide and may be injured if planted in soil treated with Sencor during the year of application or the following crop year.
• Fall seeded or cover crops such as wheat, oats, and rye may be injured when seeded within the same season as the application of Sencor.