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Rainfast Time for Postemergence Herbicides Commonly Used in the Everglades Agricultural Area: Quick Reference Sheet

D.C. Odero

If rainfall occurs soon after herbicide application, it can affect the effectiveness of postemergence herbicides. Certain postemergence herbicides differ in their time requirements for rain-free periods (rainfast) following application. The exact time required to protect herbicide activity and efficacy will vary with weed species, environmental conditions, and other factors, including the type of adjuvant added to the spray mix. It is important to always READ THE LABEL instructions on rainfastness before applying postemergence herbicides during periods when rainfall is frequent. For more information on rainfastness and pesticide use, see the EDIS publication PI238 – Rainfastness of Pesticides (

The table below (Table 1) shows the required time interval between herbicide application and rain-free period for postemergence herbicides commonly used in sugarcane and vegetable production in the Everglades Agricultural Area and the surrounding region.

Table 1. 

Rainfast time for postemergence herbicides commonly used in the Everglades Agricultural Area.



Publication #SS-AGR-351

Date:January 22nd, 2019

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Odero, Dennis Calvin


University of Florida

  • Critical Issue: Agricultural and Food Systems

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition.

Use pesticides safely. Read and follow directions on the manufacturer's label.

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  • Dennis Odero