This publication provides information about how temperature affects storage of agricultural fungicides. A table is included that lists many common agricultural fungicides registered for use in Florida along with storage limitations.
The storage temperature of pesticides influences both the effectiveness and usability of many pesticides. Labels for most liquid pesticides contain specific information on adequate storage temperatures. Generally, the labels state a temperature in the range of 40°F–100°F. For most of Florida, freezing is not a concern with pesticide storage, 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 its solvents, emulsifiers, and other inert ingredients. The result of this separation may be either crystallization or coagulation of the formulation. However, some products may be thawed and reused after adequate agitation; labels for these products 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 in regards to pesticide storage. Heat can cause some pesticides to volatilize and drift from their containers, especially if containers are not adequately sealed. Flammability is also a problem with some pesticides associated with 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).
Pesticide containers may be damaged by either temperature extreme. The container's integrity can be destroyed by freezing temperatures, which can cause glass, metal, and plastic materials to break. Also, high temperatures can cause plastic containers to melt and glass to explode. The liquid pesticide contents in metal drums can cause expansion and eventual rupturing of the container (Figure 1).
Generally, dry pesticide formulations are not adversely affected by temperature extremes. The effectiveness of these pesticides is most often reduced by the presence of moisture in storage. These products have a high affinity for water, and once absorbed the pesticides may solidify into hard masses, like a tombstone formation. The packaging that surrounds dry products formulated as water-soluble packets can become brittle after absorbing moisture. If freezing occurs, the packages can break when handled.
For more information on storage temperature limitations for individual products, consult the "Storage and Disposal" section of the pesticide label (Figure 2). Labels for many pesticide products will have specific temperature limitations mentioned in this section; labels for other pesticide products may include a more general description. If you have questions regarding these limitations, consult the product's manufacturer.
General information on storage and disposal language on pesticide labels is discussed in EDIS publication PI-106 Pesticide Labeling: Storage and Disposal (https://edis.ifas.ufl.edu/pi143).
The following table provides a listing of many commonly used agricultural fungicides registered in Florida. These fungicides are listed alphabetically by active ingredient common name, along with their trade names and any storage limitation statements that may be listed on the label's "Storage and Disposal" section. The listing does not include pre-packaged fungicide mixtures.
Fishel, F.M. 2006. 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. 2006. Pesticide Labeling: Storage and Disposal. PI-106. Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/pi143.
Storage precaution statements for commonly used agricultural fungicides.