What is pesticide synergism?

• A. When two products/chemicals are mixed and this causes an increase in control activity
• B. When one product cancels the effect of another
• C. When a pesticide degrades quickly
• D. When pests develop resistance

Answer: (A)

Synergism is when two pesticides or a pesticide and a synergist, when mixed, produce greater pest control than would be expected from using them separately. This enhanced effect happens because one component boosts the other's activity—often by inhibiting the pest’s detoxification enzymes or improving penetration or persistence. A common example is adding a synergist like piperonyl butoxide to a pyrethrin formulation to make the insecticide more effective.

So the description that matches this idea is that mixing two products increases control activity beyond what either would achieve alone. The other scenarios describe different concepts: one product cancels another (antagonism), a pesticide degrading quickly is about durability rather than interaction, and pests developing resistance is a separate evolutionary process.