Canada Thistle Control

2,4-D

See "Corn, Sweet-Postemergence" in this section of this handbook.

bentazon (Basagran)

See "Corn, Sweet-Postemergence" in this section of this handbook.

clopyralid (Stinger)

See "Corn, Sweet-Postemergence" in this section of this handbook.

Rate Apply 0.124 to 0.25 lb ae/a (0.33 to 0.66 pint/a of Stinger)

Time Any time after sweet corn emerges until it is more than 18 inches tall.

Remarks To control Canada thistle, apply when most thistle plants have emerged and thistles are at least 6 to 8 inches wide or tall, but before bud stage. For best results on Canada thistle, use at least 0.5 pint/a product. Do not cultivate before treatment; wait two weeks after treatment before cultivation. Re-treat as necessary but do not exceed 0.66 pint/a product per calendar year.

Caution Note crop rotation restrictions.

Site of action Group 4: synthetic auxin

Chemical family Pyridine

glyphosate (numerous product names)

Rate Consult labels.

Time Apply at late-bud to early-bloom stage of thistle, but before corn silking.

Remarks Spot-spray thistle patches, eliminating weed and crop in the treated area. Spray before corn silking to avoid residue in harvested crop.

Caution Do not treat more than 10% of the acreage.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted