2018 Crop Protection Guide for Tree Fruits in Washington

General Recommendations

Saturday, June 23, 2018

Formulations

Wettable powders (WP) are dry forms of pesticides. The toxicant is mixed with special powders; wetting agents are added to make the mixture blend readily with water. Wettable powders form a suspension-type spray which must be kept agitated in the spray tank. This type of formulation is often recommended for use in tree fruits because it is less likely to cause fruit and foliage injury.

Liquid concentrates (L or LC) are formulations containing toxicants which are water soluble. No emulsifying agents or organic solvents are required.

Note—The designations L and LC are sometimes used by formulators to indicate emulsifiable concentrates.

Emulsifiable concentrates (EC) contain a pesticide and an emulsifying agent in a suitable solvent. These materials are diluted with water and applied as sprays. They leave much less visible residue than WP formulations, but are much more likely to injure fruit and foliage.


Spray concentrates (SC) are liquids containing a high percentage of active ingredient. May be diluted.

Dry flowable (DF) or Water dispersible granules (WDG) formulations are similar to wettable powders except that the powders (clay particles) are formed into tiny spheres. They do not tend to pack together so they “flow” easily from the product container.

Flowable (F) formulations are a liquid or viscous concentrate of suspendible pesticide in water. They usually cause less injury to fruit and foliage than EC formulations and generally, but not always, are as safe as WP formulations.

Soluble powders (SP or S) are powder formulations that dissolve in water. A few pesticides and many fertilizers are prepared as soluble powders.

Dusts (D) are usually made by mixing the chemical toxicant with finely ground talc, clay, or dried plant materials. Because of extreme drift hazards, dusts are now seldom used in orchards.

Granules (G) are formed by saturating an inert carrier with pesticide. The particles are 30 to 60 mesh size. Granules are usually used for soil-or water-dwelling pests.

Controlled release (CR) are capsules or beads of timed release pesticides.

Baits consist of a poison plus a substance which will attract the pest. In orchards, they are used in cover crops and around tree trunks or as a cherry fruit fly control. They are less hazardous to the general environment than many sprays and dusts. Birds and other animals, however, do feed occasionally on some baits and may die if they eat large amounts.  

Tree Fruit Research & Extension Center, 1100 N Western Ave, Washington State University, Wenatchee WA 98801, 509-663-8181, Contact Us