Pest Identification and Integrated Pest Management
IPM as a decision process
IPM runs in a loop: identify the pest, monitor the population, compare it to a threshold, select the least disruptive effective tactic, then evaluate the result. Tactics are usually grouped as cultural, mechanical or physical, biological, and chemical. Pesticides are one tool, not the default first step.
Identification skills
The exam expects you to separate broad groups. Insects: chewing pests remove tissue, while piercing-sucking pests cause stippling, curling, and honeydew, and the immature stages may look nothing like the adult. Weeds: grasses have parallel veins, sheaths, and ligules; broadleaves have netted veins and paired cotyledons. Plant problems: abiotic injury tends to follow spray patterns, field edges, or weather events and appears uniformly across species, while pathogens and insects often spread from a focus.
Thresholds
An economic injury level is the pest density at which damage equals the cost of control. The economic threshold is set slightly below it so action happens before losses occur. Treating on a calendar schedule rather than a threshold is a classic wrong answer.
Resistance management
Rotate modes of action using the group numbers on the label, not just brand names, and apply full labeled rates. Recognize three distinct failures: resistance (the pest survives the labeled rate), resurgence (natural enemies were killed, so the pest rebounds), and a secondary pest outbreak (a formerly minor species fills the niche).
Worked example
Your sweep-net count averages 6 aphids per sweep against a threshold of 10. No treatment is justified; resample in a few days. Treating now spends money and accelerates resistance selection.