Which characteristic is generally true for contact pesticides?

Contact pesticides are designed to kill pests on contact, meaning they need to directly hit the target pest to be effective. This characteristic inherently means that they often do not have a long-lasting effect because once the pesticide has dried or been washed away, its efficacy decreases significantly. As a result, reapplication is typically necessary to ensure ongoing pest control.

The need for frequent reapplications arises from their quick degradation and limited residual action. This frequent maintenance is necessary to keep pest populations under control, especially in environments where new pests may continually invade or where existing pests can quickly repopulate.

Options suggesting a long-lasting effect or providing internal protection are generally misleading for contact pesticides, as their formulation and application are intended for immediate effects rather than prolonged pest control. Additionally, the impact on soil health is usually not a primary concern specifically tied to contact pesticides, as their main action is on surface pests without comprehensive systemic activity that would impact soil ecosystems.