Integrated Pest Management and Pesticide Selection

What Is Integrated Pest Management?

Integrated Pest Management (IPM) is a science-based decision-making framework that uses multiple tactics to keep pest populations below levels that cause unacceptable damage, while minimizing risk to human health, beneficial organisms, and the environment. IPM does not mean zero pesticide use; it means pesticide use is the last option considered, not the first.

IPM is organized around four steps: monitor and identify, set an action threshold, evaluate control options, and apply the best tactic or combination of tactics.

Step 1 — Monitor and Identify

Accurate pest identification is the foundation of every IPM decision. Applying the wrong product because you misidentified a pest wastes money, can harm non-target organisms, and may be illegal if the product is not labeled for that pest. Use hand lenses, sticky traps, sweep nets, or soil sampling to collect specimens, then confirm identity using extension publications, diagnostic labs, or vetted digital keys.

Monitoring also means tracking population levels over time. A single aphid on one shrub is not the same problem as hundreds per shoot across the entire planting.

Step 2 — Action Thresholds

An action threshold is the pest density or damage level at which the cost of doing nothing exceeds the cost of taking action. Below the threshold, no intervention is needed. Thresholds are pest-specific, site-specific, and sometimes client-specific — a golf course putting green has a much lower tolerance for grubs than a roadside median.

A related concept is the economic injury level (EIL): the lowest pest population that causes economic damage equal to the cost of control. The action threshold is set below the EIL so you act before losses occur.

Step 3 — Evaluate Control Tactics

IPM asks you to consider tactics in this sequence, using the least disruptive option that will achieve the threshold:

Cultural controls change the environment to make it less favorable for pests. Examples: proper irrigation timing to reduce fungal pressure, selecting pest-resistant cultivars, mowing at the correct height to promote turf density.

Biological controls use living organisms — predatory insects, parasitic wasps, beneficial nematodes, or microbial agents such as Bacillus thuringiensis (Bt) — to suppress pest populations.

Mechanical and physical controls include trapping, hand-pulling weeds, row covers, and soil solarization.

Chemical controls are used when non-chemical tactics alone will not keep the pest below threshold, or when speed of action is required. Even within chemical controls, you continue to choose the lowest-risk option available.

Step 4 — Pesticide Selection as a Last Resort

When a pesticide is necessary, selection is guided by the label — the legal document that governs every aspect of use. Compare products registered for your target pest using these criteria:

• Toxicity category: Signal words (DANGER, WARNING, CAUTION) indicate acute toxicity to humans. CAUTION products generally present lower acute risk.
• Environmental fate: Look at water solubility, soil half-life, and potential for runoff or leaching. Products with long soil residues near waterways carry higher environmental risk.
• Selectivity: Broad-spectrum insecticides harm beneficial insects; selective options target a narrower range.
• Re-entry interval (REI) and pre-harvest interval (PHI): REI protects workers; PHI protects consumers on edible crops. Both are legally binding.
• Mode of action (MOA) group: IRAC (insects/mites), FRAC (fungi), and HRAC (herbicides) assign numbered or lettered MOA codes to every pesticide. Rotating among different MOA groups is the primary tool for resistance management.
• Cost and logistics: The least-risk product still has to be practical to obtain and apply.

Resistance Management

Pesticide resistance occurs when repeated exposure to a single MOA selects for individuals in a pest population that can survive the treatment. Survivors reproduce, and the resistant trait spreads. Resistance has been documented in weeds, insects, and plant pathogens worldwide.

The solution is MOA rotation: alternate products from different IRAC, FRAC, or HRAC groups so no single mechanism is selected for repeatedly. Mixing MOA groups in a single application (tank-mix) can also delay resistance but does not replace rotation. Keeping populations low through cultural and biological tactics reduces the total selection pressure on any one chemical.

Safety Reminders

Pesticide selection and use carry legal and safety obligations:

• Always read the label before purchase, before mixing, and before application. The label is a federal legal document; deviation is a violation.
• Wear the PPE specified on the label — at minimum, chemical-resistant gloves and eye protection for most products.
• Follow lockout/tagout procedures when servicing spray equipment.
• Store pesticides in original, labeled containers in a locked, ventilated space, separated from food, feed, and seed.
• Know the location of emergency eyewash, the SDS, and the Poison Control Center number before beginning work.

By working through the IPM decision tree systematically, you protect the client's landscape, protect yourself and co-workers, protect the environment, and demonstrate the professional judgment that both the State Pesticide Applicator license and the NALP Landscape Industry Certified credential require.