However, surfactants are designed to be efficacious for a variety of pesticides and crops, as it is impractical to develop crop-specific products.Ī pure surfactant does not mix readily in water instead, it sinks to the bottom of the spray tank. For optimum performance, surfactants should be tailored to the active ingredient and the crop characteristics. Penetrating surfactants expedite movement of the active ingredient through leaf cuticles and other morphological structures. Leaves are covered with a cuticle that protects the plant from the environment and from foreign materials, including the active ingredients in most pesticides. Most pesticides are oil based and require emulsifying surfactants, which form a “bridge” between unlike chemicals that don’t mix readily. Surfactants act as dispersing agents to prevent this. Poorly formulated pesticides may flocculate, aggregate, sink, or float. A product poured into a spray tank should disperse readily in the water. Adjuvant surfactants help stabilize formulations by keeping ingredients together. They add these for at least four reasons: formulation stability, dispersibility, emulsifiability, and efficacy.įor instance, products stored for long periods of time or in extreme temperatures must not separate. Pesticide Formulators Include Adjuvants in Their Productsįormulators normally include two or three ionic and nonionic surfactants in their pesticide products. Consequently, data pertaining to the earlier formulations do not apply to the current product. In some cases, when one manufacturer stops making an adjuvant, another picks it up and formulates a similar product under the same brand name.įor example, a spreader that originally was formulated as a nonylphenol ethoxylate surfactant with an isopropyl alcohol cosolvent is now a mixture of nonylphenol and linear alcohol surfactants with a glycol in place of the low molecular weight alcohol. Only adjuvants whose value is supported by data derived from university or independent research are discussed in this section.Īdjuvant terminology is not standardized and is often confusing. Consequently, adjuvant labels, unlike pesticide labels, can make any claim. Adjuvants are not regulated by EPA other than being exempt under CFR 40 180:1001(c) or when mentioned on a pesticide product label. While all claimed uses should result from the favorable outcome of performance tests, most don’t they simply reflect the formulators’ market research. However, adjuvant label claims may not be validated by research. Properly applied adjuvants can increase pesticide efficacy (allowing for reduced pesticide use) overcome adverse environments minimize loss via evaporation and drift lessen environmental hazards and improve economic returns. In other Pacific Northwest states where registration is not required, retailers sell from 400 to 500 adjuvants. Retailers sell well over 300 registered adjuvants in Washington State. Deposit builders (stickers, film formers).Stabilizing agents (emulsifiers, dispersants, antiflocculating agents, compatibility agents).Surfactants (wetting agents, spreaders, penetrants).Crop oil concentrate (vegetable oil base with 15% to 20% surfactant/emulsifier).Petroleum oils (paraffin and naphtha based). Spray tank adjuvants represent diverse and complex chemical types, which include the following: They are meant to complement the formulation adjuvants (inert ingredients in the pesticide formulation). Spray-tank adjuvants usually are added to the spray tank at the time of mixing. Rinehold, SSB Consulting and Jeffrey Jenkins, OSU
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