5.4 Pest Identification & Pest Management Methods

5.4 Pest Identification & Pest Management Methods

Every pesticide decision begins with a correctly identified pest. The National Pesticide Applicator Certification Core Manual (NASDARF, 2nd edition, 2014), which DEEP lists as a core study text, opens with pest management for this reason. Misidentifying a pest wastes product, fails to control the problem, and can break the law if the pest or site is not on the label. This section covers what a pest is, how to identify one, and the six applied control methods. IPM, which combines those methods, follows in Section 5.5.

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What Is a Pest?

The core manual defines a pest as an undesirable organism that injures humans, desirable plants and animals, manufactured products, or natural substances. Connecticut's statute borrows the federal definition at 40 CFR 152.5, and defines a weed simply as "any plant which grows where not wanted" (CGS § 22a-47(aa)).

The four main groups of pests

Key, secondary, and occasional pests

• Key pests cause major damage on a regular basis unless controlled. Many weeds are key pests; so are cockroaches and rodents indoors, because their droppings, shed skins, and hairs can trigger asthma.
• Secondary pests become a problem only when a key pest is controlled or absent. For example, a weed species may take over after a more competitive weed is removed, or fleas may bite people after a pet leaves the home.
• Occasional pests cause trouble only once in a while because of life cycles, weather, or human activity, such as ants moving indoors after rain floods their outdoor food source.

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Identifying the Pest

Never classify an organism as a pest until it is clearly determined to be one. — core manual principle

Accurate identification lets the applicator learn the pest's life cycle, behavior, characteristic damage, favorable conditions, susceptible life stage, and known controls. The core manual's tools:

• Reference materials: identification books, Extension bulletins, field guides, and online keys with pictures.
• Expert help: send specimens to a university diagnostic lab or a local pest management specialist. In Connecticut, UConn Extension's Plant Diagnostic Laboratory and the Connecticut Agricultural Experiment Station both identify plant pests and diseases. Collect several specimens if possible and ask how to package them.
• Magnification: a hand lens or microscope is often needed for small insects, mites, nematodes, and pathogens.
• Host and location clues: the plant or animal the organism lives on, where it was collected, the environmental conditions, and the time of year.
• Life-stage changes: weed seedlings rarely look like mature plants, and insects change form from egg to immature stages to adult.

Characteristic damage

Signs can identify a pest even when it is not seen: characteristic nests of birds and rodents; insect feeding damage and excrement; mammal burrows, gnaw marks, tracks, trails in grass, and feces; weeds' unique flowers, seeds, or growth habits; and the deformation or discoloration that pathogens cause in host tissue.

Do not blame a pest for abiotic damage

Plants are also injured by non-living (abiotic) factors — weather extremes, air pollutants, road salt, and too little or too much fertilizer. The core manual warns that this damage may be mistaken for pest damage. Spraying for an imagined pest is a label-and-law problem as well as a waste: CGS § 22a-61(f)(1)(C) lists "applying pesticides generally known in the trade to be ineffective or improper for the intended use" as a ground for discipline.

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Natural Controls vs. Applied Controls

Natural controls — climate (wind, temperature, sunshine, rain), natural enemies, and topographic barriers such as rivers, lakes, and mountains — keep many organisms in check without human action. When natural controls fail, people use applied controls. The core manual lists six:

Biological control in more detail

• Classical biological control reunites an introduced pest with natural enemies from its native range. This requires extensive testing so the enemies do not become pests, and importation is strictly regulated. Once established, the enemies can suppress the pest for long periods without further intervention.
• Augmentative (mass release) control releases large numbers of commercially reared enemies — predatory mites for spider mites, parasitic wasps for specific pests. Results are usually short-term, so releases are repeated.
• Conservation maintains native enemies by providing pollen and nectar plants and by choosing pesticides less toxic to them. Where the label allows and it is effective, lower-than-label rates also reduce harm to natural enemies (FIFRA § 2(ee) permits lower rates).

Chemical control: names by target

The core manual groups pesticides by the pest they control: avicides (birds), bactericides, fungicides, herbicides, insecticides, miticides/acaricides (mites), molluscicides (snails and slugs), nematicides, ovicides (eggs), piscicides (fish), predacides (predatory vertebrates), and rodenticides. It also lists defoliants (cause leaves to drop), desiccants (dry plant tissue), disinfectants/antimicrobials, growth regulators, pheromones (attract insects), chemosterilants, and repellents.

Three properties shape how a chemical is used:

1. Selectivity: selective pesticides affect some organisms but not others — for example, broadleaf herbicides that spare grasses. Nonselective pesticides, such as fumigants, kill a wide range of organisms.
2. Movement in the host: systemic pesticides are absorbed and moved within a plant or animal; contact pesticides must touch the pest or a surface it frequents.
3. Persistence: residual pesticides stay active for weeks, months, or years; others last only hours.

Pesticides in the same class share chemical structure or a mode of action — how they kill the pest. Examples include organophosphates, carbamates, pyrethroids, and neonicotinoids. Mode of action matters for resistance management (Section 5.5).

Regulatory control: quarantine and eradication

• A quarantine prevents certain pests from entering pest-free areas, or moving within a state. Items shipped from a quarantine area must be treated, and nursery stock, cuttings, seed, and grafting material are regulated.
• Eradication eliminates a pest from a designated area, usually an exotic or introduced pest under quarantine, through area-wide spraying, sterile-insect releases, and intensive monitoring. Governments may also destroy weeds and plants that are fire hazards or harbor harmful organisms, and mosquito abatement laws let agencies drain or treat breeding water. In Connecticut, regulatory pest control (Category 9) is limited to government employees.

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Choosing Among Methods

The core manual's rule is to select the methods that are most effective against the pest yet least harmful to people and the environment, and to consider nonchemical methods first because they may give longer-lasting control. Connecticut's certification statute requires applicants to show knowledge of IPM and of protecting honey bees (CGS § 22a-54(c)(1)). The operator manual gives two Connecticut examples:

• Lawn IPM: proper liming, watering, fertilizing, and mowing height keep turf healthy, so weeds, diseases, and insects do less damage.
• Carpenter ants: because they favor decaying or moist wood, replace moist and decaying wood and remove shrubbery touching the siding, which may be their route of entry, before or alongside any treatment.