Integrated Pest Management and Decision-Making
The IPM sequence
Candidates must be able to state the IPM hierarchy in order: prevention and cultural controls first (resistant cultivars, sanitation, crop rotation, proper irrigation and fertility, physical barriers), then monitoring, then biological and mechanical tactics, then - only when justified - chemical control. Questions test whether you can place a tactic in the correct tier and whether you understand that pesticides are a component of IPM, not its opposite.
Learn the vocabulary precisely. Monitoring means regular scouting with a defined method (sweep net, sticky trap, visual counts on a set number of plants). An action threshold is the pest density at which intervention is warranted; an economic injury level is the density at which damage equals control cost. Traps: confusing threshold with economic injury level, or treating a threshold as a fixed number when it varies with crop stage, market value and natural enemy presence.
Resistance management and decision traps
Understand resistance management: rotate among mode-of-action groups, avoid repeated applications of one group, and use full labelled rates. Sub-lethal or partial-rate applications select for resistance. Also know that calendar spraying ignores monitoring and is a classic wrong answer.
Other traps: choosing a broad-spectrum product when a selective one would spare natural enemies; ignoring pollinator foraging times; and failing to record why a treatment was applied. A defensible decision names the pest, the monitoring count, the threshold, the chosen tactic and the evaluation plan.
Worked example: scouting finds 4 aphids per leaf on 20 of 50 sampled leaves; the crop-stage threshold is 10 per leaf. Correct decision: no pesticide now, re-scout in five to seven days, encourage predators, and document the counts. Applying product at 4 per leaf would be below threshold and therefore incorrect.
Rule of thumb: if you cannot state the threshold and the monitoring count that exceeded it, you have not justified an application.