Blueweed or viper's bugloss (Echium vulgare) and Paterson's curse (Echium plantagineum)

2,4-D amine

Rate Broadcast treatment: 2 lb ae/a (2.1 quarts/a)

Time Apply in spring to seedlings. Treatments from mid-summer to autumn may help control more established plants.

Remarks 2,4-D is usually not able to fully control these species, so combining with other products is generally recommended for full control.

Caution Avoid drift to sensitive crops.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid

chlorsulfuron (Telar and others)

Rate Escort: 0.75 to 1.125 oz ai/a (1 to 1.5 oz/a)

Time Apply preemergence in autumn, or postemergence to seedlings in spring. Treatments from mid-summer to autumn may help control more established plants.

Remarks Add 0.25% by volume of nonionic surfactant to spray mixture. Resistance of blueweed to sulfonylurea herbicides has been documented in Australia, so combination with other herbicides of different mode of action is recommended to delay onset of resistance.

Caution Avoid contacting sensitive crops. Apply only to pasture, rangeland, and non-crop sites.

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

Chemical family Sulfonylurea

glyphosate

Rate Broadcast: 0.21 to 0.77 lb ae/a (6 to 22 fl oz/a). Spot treat: use 1% to 2% solutions.

Time Apply from late spring to midsummer prior to flowering.

Remarks Treat all emerged foliage, but prior to runoff. Add nonionic surfactant if not included in the formulation.

Caution Glyphosate is nonselective and other vegetation will be injured or killed.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

metsulfuron (Escort and others)

Rate 0.3 to 0.6 oz ai/a (0.5 to 1 oz/a)

Time Apply in spring to seedlings. Treatments from mid-summer to autumn may help control more established plants.

Remarks Add 0.25% by volume of nonionic surfactant to spray mixture. Repeat applications will likely be necessary to achieve full control. Resistance of blueweed to sulfonylurea herbicides has been documented in Australia, so combination with other herbicides of different mode of action is recommended to delay onset of resistance.

Caution Avoid contacting sensitive crops. Apply only to pasture, rangeland, and non-crop sites.

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

Chemical family Sulfonylurea

picloram (Tordon)

Rate 4 to 8 floz ae/a (1 to 2 pints/a)

Time Apply preemergence in autumn, or postemergence to seedlings in spring. Treatments from mid-summer to autumn may help control more established plants.

Remarks Treat all emerged foliage, but prior to runoff.

Caution Most formulations are restricted-use herbicides. Do not contaminate water. Potatoes, beans, and many other broadleaf crops are sensitive to picloram. Do not use picloram in diversified cropping areas.

Site of action Group 4: synthetic auxin

Chemical family Pyridine