Spinosad is a low-risk, bio-rational pesticide that always provides effective control of caterpillars.

• A. True
• B. False
• C. Not always
• D. Depends on formulation

Answer: (B)

Spinosad is a low-risk, bio-rational option that works well against many caterpillars, but its effectiveness is not universal. Different caterpillar species and even different life stages within a species vary in how susceptible they are to spinosad. Some caterpillars may be harder to kill because they feed in ways that limit exposure, or because they’re in leaf folds or webbing that protects them from the product. The pesticide also relies on contact or ingestion, so timing matters: if you spray when most caterpillars aren’t feeding or after the product has degraded from rain, sunlight, or temperature, control drops. Resistance can develop with repeated use, reducing efficacy over time. Because of these factors, you can’t guarantee that spinosad will always provide effective control of all caterpillars; you have to match the product to the specific pest, apply at the right time and rate, and follow label conditions.