Table 12.3. Herbicides approved for managing weeds in onion. (continued)
Labels change frequently. Be sure to read a current product label before applying any chemical.
Active ingredient Trade name MOA
lb. a.i./A product/A code Crops Weeds controlled / remarks
DCPA (Dacthal) W-75 3 Onion (dry bulb, green), leek, shallot Annual grasses and certain broadleaf control. Apply at seeding or
4.5 - 6.0 6 - 8 lb. planting. Maximum rate of 10.5 lb. a.i./A per season.
(Dacthal) 6 F
6 - 8 lb.
Flumioxazin (Chateau) 51 WDG 14 Garlic, onion (dry bulb) Broadleaf control. Apply to transplanted onions between the 2- and
6- leaf stage. Apply to direct seeded onions between the 3- and
6- leaf stage.
up to 0.06
Glyphosate (various formulations) 9 Onion, garlic, leek, chive, shallot Control of emerged broadleaf and grass weeds. Consult individual
consult label labels for restrictions.
(Goal 2XL) 2 EC 14 Onion (dry bulb), garlic (dry bulb) Certain broadleaf weeds. Transplanted only. Apply within 2 days of
transplanting. Necrotic lesions, twisting, or stunting of plants can
occur if applications are made during cool, wet weather or prior to
the full development of the true leaves.
2 2.0 pt.
(GoalTender) 4 EC
1.0 pt.
Paraquat (Gramoxone) 2 SL 22 Onion (dry bulb) Controls emerged weeds. Apply prior, during, or after planting, but
before crop emergence. Only 2 applications a season. Use a nonionic
surfactant.
0.5 - 1.0 2 - 4 pt.
Paraquat (Gramoxone) 2 SL 22 Onion (seeded), garlic Emerged broadleaf and grass weeds. Apply as a preplant burndown.
0.63 - 1.0 2.5 - 4.0 pt. A maximum of 1 lb. a.i./A per season.
(Firestorm) 3 SL
1.7 - 2.7 pt.
Pelargonic acid (Scythe) 4.2 EC 27 Onion, garlic, leek, chive, shallot Emerged broadleaf and grass weeds. Apply before emergence of
crop. Product is a contact, nonselective, foliar applied herbicide.
There is no residual activity.
3 - 10% v/v
Pendimethalin (Prowl) 3.3 EC 3 Onion (dry bulb), shallot (dry bulb),
garlic
Mineral soils: Apply when crop has 2 to 9 true leaves. Muck soils:
May be applied as sequential application: preemergence through
loop stage, early postemergence (2 to 6 true leaf stage), late
postemergence (6 to 9 true leaf stage). Do not exceed 5.9 lb. a.i./A
in a growing season. PHI 45 days.
mineral mineral 1.2 - 1.8 pt.
0.5 - 0.75 muck 2.4 - 4.8 pt.
muck (Prowl H20) 3.8
1.0 - 2.0 mineral 1.0 - 1.5 pt.
muck 2.0 - 4.0 pt.
(ET Herbicide/Defoliant) 14 Bulb vegetables Emerged broadleaf and grass weeds. Apply as a preplant burndown
0.001 - 0.003 treatment.
*** POSTEMERGENCE ***
Bromoxynil (Buctril) 2 EC 6 Onion (Dry bulb) Broadleaf weeds. Soil and onion leaves should be dry before
application. Waxy coating on leaves reduces chances for injury.
Varieties vary in sensitivity, so use on a trial basis.
0.25 - 0.38 1.0 - 1.5 pt.
(Buctril) 4 EC
0.5 - 1.5 pt.
Bromoxynil (Buctril) 2 EC 6 Garlic Broadleaf weeds. Apply after emergence but before 12 in. tall.
Weeds are most susceptible up to the 4-leaf stage or 2 in. height or
1 in. wide. PHI 112 days.
0.38 - 0.5 1.5 - 2.0 pt.
Carfentrazone (Aim) 1.9 EW 14 Onion (dry bulb), garlic, leek, chive,
shallot
Emerged broadleaf control. Post-direct hooded application to row
middles for burndown of emerged weeds. Use crop oil concentrate
or nonionic surfactant at recommended rates. PHI 0 days.
up to 0.031
(Aim) 2.0 EC
Clethodim (Arrow, Select) 2 EC 1 Onion (dry bulb), garlic, shallot (dry
bulb)
Annual and perennial grass control. Some labels include green
onion. Consult label for use of a crop oil concentrate or nonionic
surfactant. PHI 45 days.
0.09 - 0.25
(Select Max) 1 EC
0.07 - 0.25
Clethodim (Arrow, Select) 2 EC 1 Chive, leek Emerged annual and perennial grasses. Consult labels rate of COC
or NIS. Do not apply more than 0.5 lb. a.i./A per season. Select Max
is not registered in leek. PHI 14 days.
0.09 - 0.13
(Select Max) 1 EC
DCPA (Dacthal) W-75 3 Onion (dry bulb, green), leek, shallot Annual grasses and certain broadleaf control. Apply at layby up to 14
weeks after planting. If weeds have emerged then cultivate or hand
weed. Maximum rate of 10.5 lb. a.i./A per season.
4.5 - 6.0 6 - 8 lb.
(Dacthal) 6 F
6 - 8 pt.
204 2019 Vegetable Production Handbook of Florida