MT Pesticide Applicator cheat sheet

Economic injury level: EIL = C ÷ (V × D × K), where C is control cost per acre, V is crop value per unit yield, D is yield loss per pest unit, and K is the proportion of loss prevented by treatment.

The economic threshold is set at or below the EIL so treatment occurs before pest density reaches the level at which loss exceeds control cost.

Preharvest interval (PHI) and restricted-entry interval (REI) are independent label values: PHI governs harvest timing, REI governs worker reentry, and both must be met.

Rotate herbicide MOA groups (HRAC) and insecticide IRAC groups within a season and across years; repeated use of a single group selects resistant biotypes.

Sprayer output formula: GPA = (GPM × 5940) ÷ (MPH × swath width in inches); recalibrate after any nozzle, pressure, or speed change.

A temperature inversion exists when air temperature rises with height; fine droplets remain suspended and move off-target, so do not spray until the inversion breaks.

Soil-applied herbicides require moisture for activation, and incorporation depth must match the label so the herbicide sits in the weed germination zone.

Scout in a W or 5-of-5 pattern and treat on pest counts or percent-infested plants rather than by calendar date.

Coarser droplets, lower boom height, drift-reduction nozzles, and adequate buffers reduce off-target movement; avoid spraying when wind exceeds label limits or blows toward sensitive crops.

Horn fly treatment is commonly triggered near 200 flies per animal, while face fly thresholds are much lower (roughly 10–20 per face) because of pinkeye transmission.

Observe label withdrawal periods for meat and milk; for the same product, milk withdrawal often differs from meat withdrawal.

Dose livestock products by body weight and label species; cattle, sheep, and goat products are not interchangeable off-label.

Delivery options include insecticide ear tags, pour-ons, backrubbers, dust bags, sprays, and feed-through larvicides; rotate IRAC groups because horn flies develop pyrethroid resistance quickly.

Feed-through larvicides such as methoprene and diflubenzuron pass into manure and prevent larval fly development; they do not control adult flies.

Systemic pour-ons such as ivermectin control some internal parasites and ectoparasites but leave residues that harm dung-breeding insects.

In barns and poultry houses, rodent baits go in tamper-resistant stations placed away from feed, eggs, and animals to limit primary and secondary poisoning.

Confinement buildings are managed first with sanitation, ventilation, and removal of fly breeding material before insecticides are applied.

Bark beetle strategy: thin stands to raise tree vigor, remove infested trees (sanitation), and use anti-aggregation pheromones such as verbenone to protect residual trees.

Bt var. kurstaki controls early-instar caterpillars (spongy moth, budworm) only when ingested; it has no contact activity and must be applied to foliage before larvae enter the tree.

Trunk injection of imidacloprid or dinotefuran targets sap-feeding pests such as hemlock woolly adelgid; emamectin benzoate injections are used against emerald ash borer.

Aerial forestry applications require labeled droplet size and swath width, flagged flight lines, and buffers along streams and sensitive areas.

Site preparation and conifer release herbicides must be chosen for tolerance of residual crop trees; soil-active products can injure trees through root uptake.

Forest management lowers susceptibility through species diversity, age-class diversity, and reduced stress from drought or soil compaction.

Key invasive forest pests: spongy (gypsy) moth, emerald ash borer, hemlock woolly adelgid, and Asian longhorned beetle.

Preemergence turf herbicides (prodiamine, pendimethalin, dithiopyr) must be applied before weed germination and watered in; they do not control emerged weeds.

Postemergence broadleaf herbicides (2,4-D, dicamba, triclopyr) work best at labeled temperatures; avoid mowing for 1–2 days before and after application.

White grub treatment threshold is roughly 8–10 grubs per square foot in irrigated turf; sample by cutting a 1-square-foot plug of turf and soil.

Oil and sulfur products must be separated by at least 30 days on sensitive ornamentals, and oils can injure foliage at temperature extremes.

Rotate FRAC groups for turf fungicides; repeated use of a single site of action selects resistant dollar spot and anthracnose populations.

Apply pesticides to blooming ornamentals in the evening or early morning when bees are not foraging, and do not spray open blossoms with bee-toxic products.

Irrigate granular formulations in as the label directs, otherwise granules remain on foliage and cause spotting.

Test unfamiliar products on a small area of ornamentals to check for phytotoxicity before treating the whole planting.

Treated seed carries a bright dye and must never be used for food, feed, or oil; store it in labeled containers and dispose of surplus per the label.

Metalaxyl and mefenoxam (FRAC 4) are specific for oomycete pathogens such as Pythium and Phytophthora on seed and seedlings.

Neonicotinoid seed treatments (imidacloprid, clothianidin, thiamethoxam) control wireworm and seedcorn maggot; they move systemically and raise pollinator and dust-drift concerns.

Seed treatment rates are expressed as fl oz per 100 lb of seed or mg of active ingredient per seed; calibrate the treater by seed weight, not volume.

Fungicide combinations such as captan, thiram, and strobilurins protect against seed rots and damping-off; mixing different MOA groups broadens the spectrum.

Talc or graphite flow lubricant aids planting of treated seed; excess dust increases off-site movement, so plant into adequate moisture and avoid windy conditions.

Keep the seed tag and lot number with stored treated seed for traceability, and never store treated seed where it can be mistaken for untreated grain.

Aquatic herbicide applications to waters of the U.S. require an NPDES permit in addition to state authorization; Montana also requires a 310 permit for work in streams.

Only EPA-registered aquatic formulations may be applied to water; examples include 2,4-D amine, diquat, fluridone, imazapyr, aquatic glyphosate, endothall, and copper compounds.

Treat no more than about one-third to one-half of a water body at one time to prevent dissolved oxygen depletion from decaying vegetation and resulting fish kills.

Copper compounds control algae but not rooted vascular plants; systemic herbicides such as fluridone and imazapyr are needed for submerged macrophytes.

Rotenone and antimycin are fish toxicants used in fisheries management; treated waters must be posted and applications made by permitted applicators.

Treat before weeds flower and set seed; early-season applications use lower rates and give better control of annual species.

Granular and subsurface-injection formulations reduce drift and place the herbicide in the target zone; maintain buffers around drinking water intakes and downstream uses.

Triclopyr is selective for broadleaf plants and woody species and releases grasses, while glyphosate is nonselective and injures grasses and desirable vegetation on contact.

Cut-stump, basal-bark, frill, and injection treatments place herbicide on the cambium and greatly reduce off-target drift compared with foliar spraying.

Residual bare-ground herbicides (imazapyr, diuron, bromacil, tebuthiuron) persist in soil and can move with runoff or injure roots of nearby desirable trees.

Work along ditches and streams requires aquatic-labeled formulations and appropriate buffer zones.

Drift management: apply in light but not calm wind, use coarse droplets, drift retardants, low pressure, and shielding near sensitive crops.

Integrated vegetation management combines mowing, hand cutting, and herbicides to maintain low-growing compatible vegetation that resists tall brush.

Time brush and conifer-release treatments to the labeled season to avoid injury to desirable trees and to maximize uptake.

Anticoagulant rodenticides (bromadiolone, diphacinone, chlorophacinone) cause internal bleeding; use tamper-resistant bait stations to prevent access and secondary poisoning.

Cockroach control with gel baits and IGRs requires removal of competing food and repeated placements; German cockroaches show bait aversion and pyrethroid resistance.

Subterranean termite control uses a continuous soil-applied termiticide barrier or a bait system; the barrier must be complete at the foundation and not disturbed.

Bed bug work begins with inspection of seams, headboards, and outlets; control combines heat, vacuuming, and labeled residual or desiccant products.

In food-handling establishments, never apply pesticides to food-contact surfaces or while food is exposed; use crack-and-crevice or bait placements per label.

Mosquito control uses larvicides (Bti, methoprene) in standing water and ULV adulticides when adult mosquitoes are active.

Ant control targets the colony: locate the nest, use bait or a non-repellent residual, and avoid treating only the visible trails.

Sanitation and exclusion - sealing cracks, repairing screens, fitting door sweeps - are the foundation of structural IPM before pesticides are used.

Regulatory pest control uses quarantine, inspection, certification, and compliance agreements to stop the spread of regulated pests.

Federal authority rests with USDA APHIS PPQ; state authority rests with the Montana Department of Agriculture, which issues permits and enforces quarantines.

Eradication programs target newly introduced pests such as spongy moth, Asian longhorned beetle, and emerald ash borer through delimiting survey and treatment.

Restricted-use pesticide application records must be kept at least 2 years and include the product, rate, date, site, and applicator.

Montana private and commercial applicator credentials expire and require continuing education credits for renewal.

Quarantine areas restrict movement of host material, soil, and equipment; moving regulated articles without a certificate or permit is a civil violation.

Inspect vehicles and equipment for hitchhiking pests and soil before leaving an infested site.

An Experimental Use Permit authorizes small-scale field testing of an unregistered pesticide; it does not permit commercial use or sale of treated crop without authorization.

A valid efficacy trial includes randomized replicated plots, an untreated check, a labeled standard treatment, and buffer rows to isolate treatments.

Report unexpected or adverse effects to the registrant and the state lead agency, and retain raw data, application records, and disposal documentation.

Measure efficacy as percent control relative to the untreated check, and rate phytotoxicity on a consistent scale such as 0–10.

Control drift and contamination: clean sprayers between treatments, dedicate equipment to specific products, and avoid overlapping swaths.

Demonstration plots may use registered pesticides only at labeled rates and sites; any unlabeled use requires an EUP or state research authorization.