Trifluralin (Treflan HFP)
WSSA Group 3: microtubule assembly inhibitor
A soil-applied product that is used for the control of grasses (annuals and some perennials) and many broadleaved species.
Can be used prior to transplanting as well as established vineyards. Apply before times of expected weed emergence or immediately after existing weeds are controlled. Trifluralin is best applied in the spring to provide almost season-long control of weeds. Must be mechanically incorporated 1 to 2 inches deep within 24 hrs following application to be effective and prevent loss of activity. Mixing activities should be done by equipment that will not injure vine roots. Since trifluralin (Treflan) is not leached into the soil, it is best applied in the spring and can be used in vineyards with sandy soils or sprinkler irrigation. Rates are dependent on soil type and new plantings (see label). Use lower rates on sandy soils or soil containing low organic matter levels and newer plantings. Lower rates should also be used in areas receiving less than 20 inches rainfall and irrigation. See label about mist propagated vines.
At least one weed species resistant to this mode of action documented to occur in ID, OR, or WA; data from Heap, I.
The International Survey of Herbicide Resistant Weeds. Available at www.weedscience.org
Usage for trifluralin on Grapes
Pre-Emergence (Weeds)
| Target | Rate of application | REI | PHI | MOA | Eff. | Notes |
|---|---|---|---|---|---|---|
| Annual Broadleaf Weeds | 1.0-4.0 pt | 12 | 60 | 3 | For newly planted and established vineyards, both bearing and non-bearing. For newly planted vineyards, follow rate on label based on soil type. | |
| Annual Grasses | 1.0-4.0 pt | 12 | 60 | 3 | For newly planted and established vineyards, both bearing and non-bearing. For newly planted vineyards, follow rate on label based on soil type. |