Carrot Weed Control 2007
Carrot Country
Summer 2007
What kinds of herbicide products can be used effectively to control weeds in carrot?
Bernard Zandstra, a professor and weed specialist with the
Department of Horticulture at Michigan State University
(MSU), updated growers Feb. 15 during the Empire State
Fruit and Vegetable Expo carrot session.
“Lorox is effective preemergence and postemergence on carrot
for most grasses and broadleaves,” the
researcher said. “Other herbicides labeled
for carrot include Dual Magnum and Trefl an
preemergence and Sencor postemergence.
The postemergence grass herbicides Fusilade,
Poast, Select and Roundup also are registered.”
Other Herbicides Coming
Several additional herbicides are in process
of being registered for use in carrot fields,
Zandstra said. Oxyfl uorfen (Goal) has fair to good selectivity
postemergence on carrot and would improve control of common
purslane, herbicide resistant pigweeds, common groundsel, marestail
and ragweed.
“The new formulation of oxyfl uorfen (GoalTender) should
improve crop safety for use on carrot,” he said. “Goal for carrot
is
an IR4 project, and we are waiting for company (Dow) approval
to proceed with residue trials.”
Nortron recently received a carrot tolerance and will be
registered for use on carrot in Washington and Oregon, he said,
expressing hope that the label will be expanded in the near future
to include the eastern United States. Nortron has postemergence
activity on yellow nutsedge, common chickweed, mustards and
nightshades.
Another product coming down the pike is Caparol (prometryn),
being registered on carrot through IR4; a label is expected in 2007.
Caparol is similar in activity to Lorox and has the same mode
of action (photosystem II inhibitor). It causes slightly more crop
stunting than Lorox when applied pre or postemergence, Zandstra
explained. Its primary use will be as a substitute for linuron, where
its use is restricted, or if an additional postemergence application
is needed. On the down side, weeds resistant to linuron also are
usually resistant to Caparol.
Command and Prowl herbicides are also being considered for
use in carrot. Command 3ME has been submitted to IR4, Zandstra
said. Canada is working on a registration. Its use would be for
PRE control of annual grasses and some broadleaves. One concern
is its moderate phytotoxicity under some conditions; however, carrots
grow out of it. If this product moves forward, FMC will have
to support the label, he said.
Prowl H2O 3.8 CS has tolerance and could be labeled in 2007,
the researcher predicted. It is used for PRE control of annual
grasses and prostrate spurge. It could be a substitute for Lorox
PRE. One drawback is that it provides no
control of ragweed.
“The Dual Magnum Section 24c (SLN)
label for New York has been expanded to
include carrot,” the speaker said. “Growers
need to indemnify the company from any liability
resulting from this use. To agree to the
indemnification language and obtain a copy of
the label, growers need to access the Syngenta
website at www.farmassist.com.
After registering
and signing in, click on PRODUCTS, then
SPECIAL LABELS, then INDEMNIFIED LABELS. Then you
will be able to select the state and print the Dual Magnum label.” Dual
Magnum may be used on carrots on any soil type, Zandstra pointed out. Previously,
its use was limited to high
organic soils.
Muck Soil Recommendations
The following are the researcher’s recommendations for carrot
weed control on muck soil:
1. Plant barley one week before planting carrots.
2. Lorox 0.5-1 lb product + Dual magnum 1.3 pt. PRE 1-2
weeks after seeding carrots.
3. Kill barley with Fusilade or Poast at 4-5 inches.
4. Lorox, 1-2 lb product, to kill emerged weeds at carrot 2-4
leaf stage.
5. Sencor 0.3 lb product, if needed, at 5-6 leaf stage
6. Poast, Fusilade or Select Max to kill emerged grasses.
Mineral Soil Recommendations
Zandstra’s recommendations for carrot weed control on
mineral soil:
1. Plant barley one week before carrot.
2. Lorox 0.5 lb product + Dual Magnum 0.5 pt 1-2 weeks after
seeding carrot.
3. Fusilade or Poast to kill barley at 4-5 inches.
4. Lorox 0.5 lb at carrot 2-3 leaf stage.
5. Sencor 0.3 lb at 5-6 leaf stage.
6. Poast, Fusilade or Select Max, as needed, for grass control.
© 2007
Columbia Publishing