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HS198
Weed Management in Sweet Potato1
Peter Dittmar and William Stall2
1. This document is HS198, one o a series o the Horticultural
Sciences Department, Florida Cooperative Extension Service,
Institute o Food and
Agricultural Sciences, University o Florida. Original
publication date March 1999. Revised April 2013. Visit the EDIS
website at http://edis.ias.u.edu.
2. Peter Dittmar, assistant proessor, and William Stall,
emeritus proessor, Horticultural Sciences Department, Cooperative
Extension Service, Institute o
Food and Agricultural Sciences, University o Florida,
Gainesville, FL 32611.
The use o trade names in this publication is solely or the
purpose o providing specic inormation. It is not a guarantee or
warranty o the products
named, and does not signiy that they are approved to the
exclusion o others o suitable composition.
The Institute o Food and Agricultural Sciences (IFAS) is an
Equal Opportunity Institution authorized to provide research,
educational inormation and other services only toindividuals and
institutions that unction with non-discrimination with respect to
race, creed, color, religion, age, disability, sex, sexual
orientation, marital status, national
origin, political opinions or afliations. U.S. Department o
Agriculture, Cooperative Extension Service, University o Florida,
IFAS, Florida A&M University CooperativeExtension Program, and
Boards o County Commissioners Cooperating. Nick T. Place , Dean
Sweet potatoes are a long-season crop. Weed control during
production can be dicult. Early-season competition rom
weeds is extremely critical. A major emphasis on control
should be made during this period. Growers must plan a
total weed control program that integrates mechanical and
cultural methods with the use o herbicides.
At the present time, there are only our herbicides that
provide preemergence control o weeds in sweet potato.Cultivation
is also an efective way to manage weeds early
in the season. Rolling cultivators either by themselves or
behind hilling blades can uproot many annual weeds that
have escaped the herbicide or have emerged since the last
cultivation. Cultivation and hilling, while useul, disrupt
the
ecacy o soil-applied herbicides. Fusilade may be applied
at any time until 55 days o harvest, and Poast or Select
may be applied up to 30 days o harvest to control emerged
grass weeds. Tese herbicides do not provide preemergence
control.
Herbicide perormance depends on weather, irrigation, soil
type, proper selection or weed species to be controlled, and
accurate application and timing (ables 1 and 2).
Figure 1. Palmer amaranth in sweet potato
Credits: Peter Dittmar
http://edis.ifas.ufl.edu/http://edis.ifas.ufl.edu/
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2Weed Management in Sweet Potato
Table 1. Pretransplant chemical weed control in sweet potato
Active ingredient
lb. a.i./A
(Trade name)
amount of product/A
Weeds controlled / remarks
CarentrazoneUp to 0.031
(Aim) 2 EC or 1.9 EWUp to 2 . oz.
Emerged broadlea weeds. Apply as a preplant burndown. Use crop
oilconcentrate or nonionic suractant at recommended rates. May be
tankmixed with other herbicides.
Clomazone0.490.75
(Command) 3 ME1.32.0 pt.
Annual broadlea and grass weeds. Use lower rates on coarse
soils.Apply within 5 days o transplanting.
DCPA
4.56
(Dacthal) W-75
68 lb.(Dacthal) 6 F68 pt.
Annual broadlea and grass weeds. Apply immediately ater
transplanting. May be applied as a layby later in the season
orpreemergence control.
Flumioxazin0.096
(Valor) 51 WDG3 oz.
Annual broadlea weeds. Do not use on sweet potato varieties
otherthan Beauregard unless user has tested other varieties and
ound
crop tolerance. Apply 25 days beore transplant and minimize
soildisturbance ater application.
Glyphosate (Various ormulations)Consult label
Emerged broadlea and grass weeds. Apply as a preplant
burndown.Consult label or individual product directions.
Napropamide
1.02.0
(Devrinol DF-XT) 50 DF
24 lb.
Annual broadlea and grass weeds. Apply immediately ater
transplanting. I rainall does not occur within 24 hrs. ater
application,incorporate or irrigate 24 inches deep.
Pelargonic acid (Scythe) 4.2 EC3%10% v/v
Emerged broadlea and grass weeds. Apply as a preplant
burndowntreatment. Product is a contact, nonselective,
oliar-applied herbicidewith no residual control. May be tank mixed
with soil residualcompounds.
Table 2. Posttransplant chemical weed control in sweet
potato
Active ingredient
lb. a.i./A
(Trade name)
amount of product/A
Weeds controlled / remarks
Carentrazone
Up to 0.031
(Aim) 2 EC or 1.9 EW
Up to 2 oz.
Emerged broadlea weeds. Apply as hooded application to row
middles
only. Use crop oil concentrate (COC) or nonionic suractant (NIS)
atrecommended rates. Contact with the leaves will cause injury. PHI
0days.
Clethodim0.090.250.070.25
(Select, Arrow) 2 EC616 . oz.(Select Max) 1 EC932 . oz.
Perennial and annual grass weeds. Use higher rates under heavy
grasspressure or larger grass weeds. Do not apply more than 0.5 lb.
a.i./A. Usea COC at 1% v/v in the fnished spray solution. Select
Max requires anNIS at 0.25% v/v. PHI 30 days.
Fluaziop0.10.25
(Fusilade DX) 2 EC616 . oz.
Perennial and annual grass weeds. Include an NIS at 0.25%0.5%
v/v orCOC at 0.5%1.0% v/v in the spray solution. PHI 55 days.
Pelargonic acid (Scythe) 4.2 EC3%10% v/v
Emerged broadlea and grass weeds. Apply as a hooded application
torow middles only. Contact with the leaves will cause injury.
Sethoxydim0.190.47
(Poast) 1.5 EC1.02.5 pt.
Growing grass weeds. A total o 5.0 pt./A applied in one season.
Includea COC. Unsatisactory results may occur i applied to grasses
understress. PHI 30 days.
