Entomology: Insect Pests of Field and Horticultural Crops
Entomology: Insect Pests of Field and Horticultural Crops
This domain tests identification by order, mouthparts, metamorphosis and damage symptom. You must link a symptom to a pest group and then to a sensible control choice.
Core rules
- Lepidoptera larvae have chewing mouthparts; adults are moths or butterflies. Damage includes holes, borings and defoliation. Examples: cotton bollworm, tomato fruit borer, rice stem borer.
- Hemiptera have piercing-sucking mouthparts. Hoppers, aphids and whiteflies remove sap, produce honeydew and transmit viruses. Examples: brown planthopper, mango hopper, citrus psylla.
- Coleoptera are beetles and weevils with chewing mouthparts; grubs may feed on roots.
- Thysanoptera have rasping-sucking mouthparts; damage appears as silvering and streaks. Onion thrips is a key example.
- Complete metamorphosis is egg-larva-pupa-adult; incomplete metamorphosis is egg-nymph-adult.
- Rice stem borer causes deadheart in the vegetative stage and white ear at heading.
Worked example
A farmer reports yellowing rice panicles. Pull affected tillers: if the panicle is empty and a larva is inside the stem, the cause is stem borer, not planthopper. Planthopper damage is a circular hopperburn patch with insects at the base. Reasoning: symptom location plus insect stage separates the two.
Traps
Calling mites insects (mites have eight legs), using a contact insecticide for a root borer, and confusing deadheart with drought or nutrient stress cost marks.