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Storage Limitation Statements: Temperature—Herbicides

Frederick M. Fishel

This guide provides information about how temperature affects storage of agricultural herbicides. A table is included that lists many common agricultural herbicides registered for use in Florida, with storage limitation statements.

Introduction

Storage temperature influences the effectiveness and usability of many pesticides. Most labels of liquid pesticides contain specific information on adequate storage temperatures for their products and will generally state a temperature in the 40°F–100°F range. Freezing is not a normal concern for pesticide storage in Florida, but extreme heat is a factor for the entire state.

Freezing temperatures can render a liquid-formulated pesticide useless by causing the active ingredients to separate from the solvents, emulsifiers, and other inert ingredients. The result may be either crystallization or coagulation of the formulation. Some products may be thawed and reused after adequate agitation; their labels will specifically state if this is the case. Because of the ingredients in the formulation, the freezing point of many products may be lower than 32°F.

Heat is the major concern in Florida for pesticide storage problems. Heat can cause some pesticides to volatilize and drift from their containers, especially if containers are not adequately sealed. Flammability is a problem with some pesticides in the presence of heat and/or open flame. For more on this topic, see EDIS publication PI-97 Pesticide Labeling: Physical or Chemical Hazards (https://edis.ifas.ufl.edu/pi134).

Containers may be damaged by either temperature extreme. Freezing temperatures can cause containers made of glass, metal, or plastic to break. Alternatively, high temperatures can cause plastic containers to melt and glass to explode. Liquid pesticide contents stored in metal drums can expand and eventually rupture (Figure 1).

 

Figure 1. Pesticide drum bulging from extreme heat.
Figure 1.  Pesticide drum bulging from extreme heat.

 

Generally, dry pesticide formulations are not adversely affected by temperature extremes. Their effectiveness is most often reduced by the presence of moisture in storage. These products have a high affinity for water and, once absorbed, may solidify into hard masses (tombstone formation). The packaging that surrounds dry products formulated as water-soluble packets can become brittle after taking on moisture; and if freezing occurs, they can break when handled.

To learn storage temperature limitations for individual products, consult the "Storage and Disposal" section of the pesticide label (Figure 2). Many products will have specific temperature limitations mentioned in this section; others may be more general. If you have questions regarding these limitations, consult the product's manufacturer.

 

Figure 2. The Storage and Disposal section of the label often contains specific temperature information.
Figure 2.  The Storage and Disposal section of the label often contains specific temperature information.

 

General information on storage and disposal language found on pesticide labels is discussed in EDIS publication PI-106 Pesticide Labeling: Storage and Disposal (https://edis.ifas.ufl.edu/pi143).

Table 1 lists many commonly used agricultural herbicides registered for Florida. They are listed alphabetically by active ingredient common names (center column) with their trade names and any storage limitation statements from the Storage and Disposal directions. Not every herbicide common active ingredient and/or their associated trade products list storage limitations on the storage statements.

Additional Information

Fishel, F.M. 2012. Pesticide Labeling: Physical or Chemical Hazards. PI-97. Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/pi134

Fishel, F.M. 2012. Pesticide Labeling: Storage and Disposal. PI-106. Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/pi143

Tables

Table 1. 

Commonly used agricultural herbicides regestered for Florida

 

 

Publication #PI-123

Date: 3/31/2019

RELATED TOPICS

Fact Sheet

About this Publication

This document is PI-123, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date June 2006. Revised April 2013 and March 2016. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.

About the Authors

Frederick M. Fishel, professor, Agronomy Department, and director, Pesticide Information Office; UF/IFAS Extension, Gainesville, FL 32611.

Contacts

  • Brett Bultemeier