See section on Soil Fumigation Outdoors in the Disease Management section. Proper use of Vapam can provide control of most weed species.
Stale Seedbed
The following herbicides are nonselective and are used to control weeds that are present in a field prior to planting or before the crop emerges, which is especially useful for the Stale Seedbed Technique (see the Weed Management section for more information).
- glyphosate (Roundup Power Max): PHI 14d, REI 4h, Group 9.
- paraquat (Gramoxone SL 3.0*): REI 48h, Group 22. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
- pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0.
Preemergent Herbicides (before weeds germinate)
HRAC Group 0:
bensulide (Prefar 4E): 5 to 6 qt/A; REI 12h. 1 application per year. Do not exceed 6 qt/A per year. Apply before planting or after planting but before crop emergence. Grass control only.
HRAC Group 3:
pronamide (Kerb SC): 2 to 4 lb/A; PHI 55d, REI 24h. Head lettuce, endive, escarole, and radicchio greens only. 1 application per year. Apply before or after planting, before crop emergence, as a banded, bed-topped, or broadcast application.
trifluralin (Treflan HFP): 1 to 2 pt/A; REI 12h. Endive and escarole only. 1 application per year. Apply in spring or early summer, before planting. Incorporate within 24 hours of application; a second incorporation pass in the opposite direction may be required.
Postemergent Herbicides (after weeds germinate)
HRAC Group 0:
pelargonic acid (Scythe): 3% to 10% solution; PHI 1d, REI 12h. Apply as a vegetative burndown during site preparation or as a directed and shielded spray during crop growth.
HRAC Group 1:
clethodim (Select Max): 9 to 16 fl oz/A; PHI 14d, REI 24h. Do not exceed 64 fl oz/A per year. Apply to actively growing grasses.
fluazifop (Fusilade DX): 6 to 24 fl oz/A; PHI 14d, REI 12h. Leaf and head lettuce only. Do not exceed 48 fl oz/A per year. Apply to actively growing grasses.
sethoxydim (Poast): 0.5 to 1.5 pt/A; PHI 30d for head lettuce, 15d for leaf lettuce, escarole, and endive, REI 12h. Do not exceed 3 pt/A per year. Apply to actively growing grasses. BASF has stopped production and will discontinue the registration at the end of 2027.
HRAC Group 9:
glyphosate (Roundup Power Max): 10 fl oz to 3.1 qt/A; PHI 14d, REI 4h. Do not exceed 5 qt/A per year. Apply during fallow intervals, prior to planting, or to row middles with a hooded or shielded sprayer or wiper applicator. Spray contact will cause crop death. Spray additive recommendation varies with formulation—see label.
HRAC Group 14:
carfentrazone (Aim EC): 0.5 to 2 fl oz/A; REI 12h. Do not exceed 6.1 fl oz/A per season. Apply as a preplant burndown up to 1 day before transplanting or up to 7 days before direct-seeding, or to row middles of emerged crops with hooded sprayers. Contact with crop will cause damage.
HRAC Group 22:
- paraquat (Gramozone SL 3.0*): 1.3 to 2.7 pt/A; REI 48h. Do not exceed 8 pt/A per year. Apply before, during, or after planting, but before crop emergence, as a banded or broadcast application. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.