Water-soluble powders

Definition

A pesticide formulation consisting of active ingredient(s) and inert carriers that dissolve completely in water to form a true solution, leaving no visible residue. Distinguished from wettable powders (which form suspensions) and emulsifiable concentrates. SP is the standard abbreviation.

Etymology

From water (Old English wæter) + soluble (Latin solubilis, able to be loosened/dissolved) + powder (Old French poudre, dust). The formulation type was developed in the mid-20th century as an alternative to emulsifiable concentrates for water-based application systems.

Example

Spinosad 25% SP, used for larval mosquito control in container habitats, is mixed at 0.1 g/L to create a clear spray solution that leaves no visible film on treated surfaces.

Synonyms

• SP
• soluble powder

Related Terms

• wettable powders
• emulsifiable concentrates
• Formulation
• pesticide application
• larval source management
• vector control

Usage Notes

Abbreviated SP in product labels and literature. Not interchangeable with wettable powders (WP/WG), which contain insoluble particles that require agitation. Water-soluble powders are preferred when visible residue must be minimized, such as in indoor residual spraying of walls or in aquaculture settings. The formulation is unsuitable for oil-soluble actives. Storage requires moisture-proof containers; caking indicates degradation.