Pest Identification and Integrated Pest Management
Identify before you treat
IPM starts with correct identification. A weed, insect, disease, or nutrient problem can produce similar symptoms, and spraying the wrong target wastes money and can injure the crop. Learn the pest’s life cycle and vulnerable stages, because many treatments work only during a narrow window. Also distinguish pest damage from abiotic stress, herbicide injury, or beneficial insect activity.
The IPM pyramid
Use prevention first: sanitation, resistant varieties, crop rotation, irrigation management, and exclusion. Then monitor with scouting, traps, and weather data. Act only when monitoring shows the pest has reached an action threshold. Prefer cultural, mechanical, and biological controls where practical. Pesticides are one tool, not the default.
Thresholds and resistance
Economic thresholds connect pest density to likely economic loss. Treating below threshold increases selection pressure and cost. Resistance management requires rotating modes of action, not just product names. Know the IRAC, FRAC, and WSSA group numbers, and follow label limits on total applications per season.
Traps
Exam questions often describe a “pest” that is actually a beneficial or a symptom of poor growing conditions. Another trap is the calendar spray: applying on a fixed schedule without scouting. Also watch for rotating between two products that share the same mode-of-action group-this does not delay resistance.
Worked example
A field has 3% aphid-infested terminals, below the label’s stated threshold of 10%. The correct action is to continue scouting and preserve beneficials, not to spray. If treatment becomes necessary later, choose a product from a different mode-of-action group than the last application.