Southeastern U.S. Vegetable Crop Handbook - 2022 - 369

WEED CONTROL
TABLE 4-27. CHEMICAL WEED CONTROL IN WATERMELONS (cont'd)
Weed
Herbicide,
Mode of Action Code*
and Formulation
WATERMELON, Preplant
Suppression or control
of most annual grasses
and broadleaf weeds,
full rate required for
nutsedge control
Contact kill of all green
foliage, stalebed
application
metam sodium
(Vapam HL) 42%
15.7 to 31.5
37.5 to 75 gal
Rates are dependent on soil type and weeds present. For nutsedge, apply 75gal
per acre. Apply when soil moisture is at field capacity (100 to 125%). Apply
through soil injection using a rotary tiller or inject with knives no more than 4 in.
apart; follow immediately with a roller to smooth and compact the soil surface or
with mulch. May apply through drip irrigation prior to planting a second crop on
mulch. Plant back interval is often 14 to 21 days and can be 30 days in some
environments. See label for all restrictions and additional information.
paraquat, MOA 22
(Parazone) 3 SL
(Gramoxone SL) 2 SL
0.5 to 1
1.3 to 2.7 pt
2 to 4 pt
Apply in a minimum of 10-gal spray mix per acre to emerged weeds before crop
emergence or transplanting as a broadcast or band treatment over a preformed
row. Row should be formed several days ahead of planting and treating to allow
maximum weed emergence. Plant with a minimum of soil movement for best
results. Use a nonionic surfactant at a rate of 16 to 32 oz per 100-gal spray mix
or 1-gal approved crop oil concentrate per 100-gal spray mix. Paraquat product
labels require applicators to take an EPA-approved training every 3 years to mix,
load, and apply paraquat.
Morningglory and small
pigweed
pyraflufen ethyl, MOA 14
(ET Herbicide) 0.208 L
1 to 2 oz
0.0016 to
0.0032
Bareground. Wait 1 day following preplant burndown application before planting.
Plastic Mulch Production. May apply over mulch; however, a single 0.5 in.
irrigation/rain event plus a 7-day waiting period must occur before transplanting.
Apply ET with a crop oil concentrated at 1% v/v to sensitive weeds that are less
than 3 in.
Emerged broadleaf and
grass weeds
Most broadleaf weeds
less than 4 in. tall or
rosettes less than 3 in.
in diameter; does not
control grasses
Annual and perennial
grass and broadleaf
weeds, stale bed
application
pelargonic acid, MOA 26
(Scythe) 4.2 EC
carfentrazone-ethyl,
MOA 14
(Aim) 1.9 EW or 2 EC
glyphosate, MOA 9
(numerous brands and
formulations)
Up to 2 oz
See labels
See label
See label
Apply as a preplant burndown treatment, or prior to crop emergence from seed,
or as a directed or shielded spray between beds. Avoid contact of watermelon
foliage.
Up to 0.031 Transplants only. Apply prior to transplanting of crop. Use a nonionic surfactant
or crop oil with Aim. See label for rate. Cover age is essential for good weed
control. Can be tank mixed with other registered herbicides.
See labels
Apply to emerged weeds at least 3 days before seeding or transplanting. When
applying Roundup before transplanting crops into plastic mulch, care must be
taken to remove residues of this product from the plastic prior to transplanting.
To prevent crop injury, residues can be removed by 0.5 in. rainfall or by applying
water via a sprinkler system. Perennial weeds may require higher rates of
glyphosate. Consult the manufacturer's label for rates for specific weeds. Certain
glyphosate formulations require the addition of a surfactant. Adding a nonionic
surfactant to glyphosate formulated with nonionic surfactant may result in
reduced weed control.
Emerged broadleaf
weeds and some annual
grasses
caprylic acid, MOA 26
(Homeplate)
See label
See label
May be applied prior to planting as a burndown treatment for emerged weeds, as
a preemergence application after seeding but before emergence, as a directed
or shielded application between rows or as a postharvest application. Use higher
spray volumes for high weed density and weeds larger than 5 in. Coverage is
important for acceptable weed control. May be tank mixed with other herbicides.
See label for further instructions.
Annual grasses
bensulide, MOA 8
(Prefar) 4 E
WATERMELON, Preemergence
Palmer amaranth,
redroot pigweed,
smooth pigweed,
galinsoga spp., black
nightshade, Eastern
black nightshade,
common purslane,
partial control of yellow
nutsedge
fomesafen, MOA 14
(Reflex) 2 EC
5 to 6
5 to 6 qt
Apply preplant and incorporate into the soil 1 to 2 in. (1 in. incorporation is
optimum) with a rototiller or tandem disk or apply to the soil surface after seeding
and follow with irrigation. Check replant restrictions for small grains on label.
10 to 12 oz
0.16 to 0.19 This is a Section 24(c) Special Local Needs Label. Growers must make sure
fomesafen is registered in their state and to obtain the label prior to making an
application. See label for further instructions.
Plasticulture transplants or seeds. May apply under plastic mulch if plastic
laying process does not disturb treated soil; thus, do not apply prior to laying
drip or forming bed. May apply over plastic mulch if the mulch is washed with 0.5
in. rainfall/irrigation in a single event prior to punching holes and planting; bed
formation must allow herbicide to wash off the mulch and not concentrate in low
areas on the mulch.
Bareground transplant. Prepare land for planting; apply Reflex; lightly irrigate to
activate herbicide and move it into soil; and then prepare plant holes and plant.
Bareground seeded. Apply within 1 day of planting; lightly irrigate after application
but at least 36 hours prior to emergence.
Row middles. Must apply prior to crop emergence or transplanting. May use up
to 16 oz per acre in watermelon.
See label for potential carryover to rotational crop.
*Mode of action (MOA) code developed by the Weed Science Society of America.
Amount of
Formulation
Per Acre
Pounds Active
Ingredient
Per Acre
Precautions and Remarks
2022 Vegetable Crop Handbook for Southeastern United States
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Southeastern U.S. Vegetable Crop Handbook - 2022

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