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Weed Management in Sweet Potato1

Peter Dittmar and Nathan S. Boyd 2

Sweet potatoes are a long-season crop. Weed control during production can be difficult. Early-season competition from 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 of herbicides.

At the present time, there are only four herbicides that provide preemergence control of weeds in sweet potato. Cultivation is also an effective 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 useful, disrupt the efficacy of soil-applied herbicides. Fusilade® may be applied at any time until 55 days of harvest, and Poast® or Select® may be applied up to 30 days of harvest to control emerged grass weeds. These herbicides do not provide preemergence control.

Herbicide performance depends on weather, irrigation, soil type, proper selection for weed species to be controlled, and accurate application and timing (Tables 1 and 2).

Figure 1. Palmer amaranth in sweet potato.
Figure 1.  Palmer amaranth in sweet potato.
Credit: Peter Dittmar, UF/IFAS


Table 1. 

Pretransplant chemical weed control in sweet potato.

Table 2. 

Posttransplant chemical weed control in sweet potato.


1. This document is HS198, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date March 1999. Revised July 2016. Reviewed January 2020. Visit the EDIS website at for the currently supported version of this publication.
2. Peter Dittmar, assistant professor; and Nathan S. Boyd, Horticultural Sciences Department; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. It is not a guarantee or warranty of the products named, and does not signify that they are approved to the exclusion of others of suitable composition.

Publication #HS198

Date: 1/22/2020

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Dittmar, Peter J.

University of Florida

Boyd, Nathan S.

University of Florida



    • Nathan Boyd
    • Peter Dittmar