Pesticides: Types, Formulations and Action

About 5 of every 50 questions on each state's practice exam (Alaska Core, Alabama General Standards, California Laws, Regulations and Basic Principles, Delaware Core, Florida Core, Georgia General Standards, Idaho Core Competency, Illinois General Standards, Illinois General Standards (Structural), Kansas General Exam, Louisiana General Standards, Louisiana Structural General Standards, Massachusetts Core, Maine Commercial Core, Missouri CORE, Montana Core, North Carolina Core, New Jersey Core, Nevada Core and Laws, New York Core, Ohio Commercial Core, Pennsylvania Core, Rhode Island Commercial Licensing, Texas General Standards (Agricultural), Texas General Standards (Structural), Virginia Core, Vermont Core, Washington Laws and Safety and West Virginia Core) come from this topic.

Sources checked November 10, 2026

What to know

Know the pesticide classes by target (for example nematicides for roundworms, growth regulators that alter plant growth) and the action terms: selective vs nonselective, contact vs systemic, preemergence vs postemergence, and residual. A formulation combines the active ingredient, the part that controls the pest, with inert ingredients, and the label signal word reflects the whole formulated product. Learn each formulation's trade-offs: emulsifiable concentrates pass easily through skin, wettable powders need constant agitation and pose a dust inhalation risk, dry flowables cut that inhalation risk, granules are ready to use with a low drift risk, fumigants are dangerous to breathe, and microencapsulated products can be carried to the hive by foraging bees. In a dry product name the number is usually percent active ingredient by weight; in a liquid it is usually pounds of active ingredient per gallon. Adjuvants such as surfactants lower surface tension, acidifiers lower pH without buffering, high-pH water can break down organophosphates and carbamates, a jar test checks only physical compatibility, the W-A-L-E-S order starts with wettable powders and WDGs, and resistance management means rotating by mode-of-action group number, which EPA recommends showing on the label.

Where it comes from

• National Pesticide Applicator Certification Core Manual (2014), Ch. 1, pp. 6–7
• NPIC, Pesticide Active Ingredients; Other/Inert Ingredients in Pesticides
• Purdue Extension PPP-31, Pesticides and Formulation Technology
• Penn State Extension, Pesticide Formulation Demonstration
• eXtension Bee Health, Which pesticide formulations are least hazardous to honey bees?
• University of Florida IFAS Extension SS-AGR-109, Adjuvants
• Michigan State University Extension, Effect of water pH on the stability of pesticides
• University of Arkansas Extension FSA2166, Assessing Pesticide-Fertilizer Compatibility (Jar Test)
• EPA PRN 2017-1, Pesticide Resistance Management Labeling
• University of Florida IFAS Extension ENY-2087, Understanding Insecticide Modes of Action and Resistance Management

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