Pesticide Formulations and Compatibility
Formulation families
Emulsifiable concentrates (EC) mix with oil solvents and water; wettable powders (WP) and water-dispersible granules (WDG or DF) form suspensions; suspension concentrates or flowables (SC) are pre-milled suspensions; solutions (S) are true liquids; granules (G) and baits are applied dry; microencapsulated products release slowly and can be hazardous to bees. Each carries tradeoffs in agitation, visible residue, phytotoxicity risk, and drift.
Adjuvants and carriers
The label may require a surfactant, and it may specify a type - nonionic, crop oil concentrate, methylated seed oil, or organosilicone. A compatibility agent helps stubborn mixes. Water conditioners such as ammonium sulfate help with hard-water antagonism, notably with glyphosate. Never exceed the labeled adjuvant rate; more surfactant increases phytotoxicity risk rather than improving control.
Tank-mix order
Fill the tank half to three-quarters with water and start agitation. Add a compatibility agent if needed, then dry formulations (WP, WDG), then liquid flowables, then emulsifiable concentrates, then surfactants and other adjuvants last. Adding an EC first and dry products afterward is a favorite wrong answer.
Diagnosing incompatibility
Clabbering, flocculation, sludge, or heat means the mix has failed; never spray it. Run a jar test first using the same product ratios in about a pint of the same water source.
Rule of thumb
When compatibility is doubtful, the jar test costs minutes and a failed tank costs a spray day, a plugged system, and possibly a crop.