On what life stage are insecticides usually most effective?

• A. Egg
• B. Larva or Nymph
• C. Adult
• D. Pupa

Answer: (B)

The life stage that’s usually most vulnerable to insecticides is the larval or nymph stage. These immature forms are typically actively feeding and growing, which means they take in or absorb pesticides more readily. They also tend to have softer bodies and fewer protective barriers than eggs or pupae, making contact and stomach poisons more effective. Eggs are protected by a tough shell and aren’t feeding, so they’re harder to kill with standard pesticides. Pupae are dormant and shielded, so they’re not exposed to the chemicals. Adults can be mobile and may escape exposure, reducing contact with the poison. So, targeting the feeding, growth phase maximizes the insecticide’s impact.