glyphosate (numerous product names)

Rate Consult labels

Time Apply 1 to 4 weeks before planting to allow time for chemical to move completely into the roots of actively growing weeds.

Remarks Use lower rates for annual weeds; consult label for higher rates and application time for perennial weeds. An additional surfactant sometimes is helpful when weeds are less vigorous. Inhibits production of three amino acids and protein synthesis.

Caution If repeat treatments are necessary within the crop, do not exceed 10.6 lb ai/a (10.6 quarts/a) in 1 year.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

C8/C10 Fatty acid blend (Fireworxx)

Rate Foliar rates: 3% by volume for young or newly germinated weeds less than 5 inches tall, moss and algae; 6% by volume for weeds larger than 5 inches, soft growth perennials and grasses; and 9% by volume for tough-to-kill weeds, vines, brush and sucker control. Tank mixing with other herbicides: 1% v/v to improve the efficacy of other herbicides; can be used to improve control of glyphosate-resistant weeds.

Time Activity is enhanced when applied during sunny or warm conditions.

Remarks FireWorxx mixes well with water. Hard or high alkalinity water may bind up the soap formulation. The use of a buffering agent will correct this. Apply at 35 to 400 gal per acre covering all plant parts of the weed(s). Perennial weeds will require higher rate of 9% and or multiple applications for optimum control.

Caution Do not allow mix to remain in tank longer than 24 hours. Do not apply through any type of irrigation system.

Site of action Group M herbicide (OMRI listed)

Chemical family Biopesticide - Soaps

soil fumigants

See the current edition of the PNW Plant Disease Management Handbook for application details and list of approved materials. Recently, a number of changes have been made on labels regarding new mitigation measures for soil fumigants including:

  • Restricted Use Pesticide classification for metam sodium and dazomet
  • New mandatory Good Agricultural Practices (GAPs)
  • Application rate reductions
  • Buffer zones requirements

More information from ODA: