Sandbur, longspine (Cenchrus longispinus)

clethodim (Select or Arrow)

Rate 0.9 to 0.125 lb ai/a

Time Apply to sandbur 2 to 6 inches tall.

Remarks See label for crops and sites where clethodim may be used. If required, apply with suitable surfactant. Acts very slowly, taking at least 2 weeks and often 4 weeks to show effects. Do not apply to stressed grasses.

Caution Do not apply if rain is expected within 1 hour.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Cyclohexanedione

fluazifop (Fusilade DX)

Rate 0.375 lb ai/a (1.5 pints/a), depending on site

Time Apply to actively growing sandbur when 2 to 8 inches tall.

Remarks See label for crops and sites. Apply with 1% (v/v) crop oil concentrate. Acts very slowly, taking at least 2 weeks and often 4 weeks to show effects. Do not apply to stressed grasses.

Caution Do not use crop oil concentrate if treating sandbur in ornamentals. Do not apply if rain is expected within 1 hour.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Aryloxyphenoxy propionate

glyphosate

Rate 0.75 to 1.5 lb ae/a

Time Apply the 0.75 rate to actively growing weeds less than 6 inches tall. If weeds are above 6 inches tall, apply 1.5 lb ae/a.

Remarks Apply as postemergence spray to sandbur foliage.

Caution Glyphosate is not selective in cropland.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted.

imazapic (Plateau)

Rate 0.063 to 0.188 lb ai/a

Time Apply early postemergence.

Remarks Plateau also has some preemergence activity. Add 1 quart/a methylated seed oil.

Caution Before using, note crop rotation restrictions.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Imidazolinone

MSMA (Bueno or Trans-Vert)

Rate 2 to 4 lb ai/a

Time Apply after sandbur emerges.

Remarks MSMA is more active above 70°F. Regrowth after rain or overhead irrigation may need respraying. Results are best when applied in the seedling stage.

Caution Keep liquid or dust away from eyes. Wash eyes immediately with water if exposed.

Site of action Group 17: not well understood

Chemical family Organoarsenical

paraquat (Gramoxone Max)

Rate 0.38 to 0.49 lb ai/a

Time Apply as a postemergence spray to sandbur foliage.

Remarks Results are best if sandbur is in seedling stage. Add 8 to 16 fl oz/100 gal nonionic surfactant to spray mix. Paraquat, a contact herbicide, requires thorough spray coverage. Sandbur emerging after application will not be controlled.

Caution A restricted-use herbicide. Do not use around homes or other areas where children or pets might come in contact with the herbicide. Do not breathe spray mist.

Site of action Group 22: photosystem I electron diversion

Chemical family Bipyridilium

quizalofop (Assure II)

Rate 0.048 to 0.55 lb ai/a (7 to 8 fl oz/a product)

Time Apply to sandbur 2 to 6 inches tall.

Remarks See label for crops and sites. Include crop oil concentrate or nonionic surfactant as label recommends. Acts very slowly, taking at least 2 week and often 4 week to show effects. Do not apply to stressed grasses.

Caution Do not apply if rain is expected within 1 hour.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Aryloxyphenoxy propionate