Pest Identification and Management
Identification first
Accurate identification drives every control decision. Know the difference between insects, mites, weeds, plant pathogens, and vertebrates, and be able to distinguish pests from beneficials and from harmless organisms. Key insect concepts: complete vs. incomplete metamorphosis, chewing vs. piercing-sucking mouthparts (which determines whether a contact insecticide will work), and the difference between immature and adult stages. For weeds, know monocots vs. dicots, annual vs. biennial vs. perennial life cycles, and how those affect control timing.
Integrated pest management
IPM is the framework: identify the pest, monitor with scouting and thresholds, use cultural and mechanical controls first where practical, then biological, then chemical as a last resort. Economic threshold is the pest density at which control pays; economic injury level is the density at which damage justifies treatment. Know resistance management: rotate modes of action, and understand that repeated use of one chemical class selects for resistant populations.
Traps in questions
- Treating without identifying - a common wrong answer; identification precedes control.
- Confusing threshold with injury level - threshold is the action point, injury level is the damage point.
- Assuming all insects are pests - many are predators or pollinators.
- Calendar spraying vs. scouting - IPM favors monitoring over fixed schedules.
Worked example
A grower sees aphids and wants to spray immediately. Scout first: count aphids per leaf and compare to the established threshold. If below threshold, hold off and re-scout; if above, select a product effective against piercing-sucking insects and rotate modes of action across the season.