Borers are insect pests that can be most effectively controlled by which type of insecticides?

• A. Biological controls
• B. Insecticidal soaps
• C. Contact insecticides
• D. Systemic insecticides

Answer: (D)

Borers feed inside plant tissues, often hidden in stems or trunks, so sprays that stay on the surface can’t reach them. A systemic insecticide gets absorbed by the plant and moves through the vascular system, reaching the areas where the larvae are feeding. When the borers ingest or contact these internal tissues, they die, giving effective control from within the plant.

Biological controls rely on natural enemies and can help, but they may not provide immediate, consistent suppression across an entire plant. Insecticidal soaps require direct contact with the insects, which isn’t feasible for borers inside wood or stems. Contact insecticides act only on pests that are exposed to the spray, so they’re not effective against internal feeders.