Our Top Sticky Traps

Sticky Traps

Yellow for most pests, blue for thrips — sticky traps for greenhouse and crop scouting.

What sticky traps target

Sticky traps are the cheapest, most useful scouting tool in a greenhouse IPM program. They have two distinct uses: monitoring (counting adults to track populations and time biocontrol releases) and mass trapping (reducing airborne adult populations of certain pests by sheer trap density). Both work, but they’re different jobs and they take different deployments — the most common mistake on a new program is hanging traps without deciding which one you’re doing.

Color choice does most of the work. Yellow traps catch the broadest spectrum of flying greenhouse and crop pests — whitefly, fungus gnats, shore flies, thrips, winged aphids, leafminers, and scale crawlers among others. Blue traps are thrips-specific: they attract thrips while letting most beneficials — especially Aphidius parasitoids — pass by, which makes them the right pick when you’re running an active parasitoid program and need to monitor thrips at the same time without catching the predator you just released.

Sticky Cards — double-sided yellow and blue sticky cards for greenhouse pest monitoring — Sticky cards ship in double-sided yellow/blue format and case quantities. Peel the backing, hang in the canopy, and monitor using the printed grid.

How they work — color attraction and trap design

Most flying greenhouse pests are visually drawn to specific colors that mimic the spectral signature of their host plants or oviposition substrates. UC IPM and UF/IFAS both confirm the same color × pest map: bright yellow is broadly attractive to whitefly, leafminer, fungus gnat, shore fly, winged aphids, and most thrips species; blue is the thrips-specific attractor (and notably not attractive to Aphidius parasitoids and most other beneficials). White traps capture Frankliniella-genus thrips better than other colors in some research, but they’re less commonly available commercially. Hot pink has shown thrips attraction in research trials but isn’t commercially produced at scale yet.

A trap by itself isn’t a control measure for most pests. UC IPM’s standing guidance: even large numbers of trapped insects don’t necessarily mean action is needed. Pair the trap counts with direct plant inspection to determine whether populations are at economically damaging levels. Counts give you the population trend; the plant tells you the threshold.

Vertical vs. horizontal orientation

Hang traps vertically just above canopy level for flying adult pests (whitefly, thrips, winged aphids, leafminer). For pests that emerge from or rest on the growing media — fungus gnats and shore flies in particular — orient the trap horizontally (sticky side down) at media level, or hang it just above the pot rim. The pest behavior decides the orientation, not the trap itself.

Yellow sticky card with various flying greenhouse insects caught on the adhesive surface — Yellow sticky card after deployment — the printed grid lines make it possible to count consistently between visits.

Crops and environments

Crops they support

Vegetable crops Fruit crops Ornamentals Tree & shrub nurseries Hemp / Cannabis Propagation

Environments

Greenhouses Indoor facilities Interiorscapes Mushroom houses Field & row crops Gardens

Storage

Store sticky traps in their original packaging at room temperature, away from heat and direct sun. The adhesive softens in heat and stiffens in cold — both conditions reduce capture efficiency. Once a trap is in service, check and replace it on a fixed schedule so the counts stay comparable between visits.

Instructions of use

Decide: monitor or mass trap

For monitoring, hang 1 trap per 250 sq. ft. in a typical mixed greenhouse, or 1 per 1,000 sq. ft. in large monoculture houses where pests cluster. Check on a regular schedule (weekly is the common cadence), count by species, and chart the results so trends are visible. The chart matters more than any single count.

For mass trapping of whitefly or fungus gnat adults, increase trap density significantly above monitoring rates. Even at high density, sticky traps alone won’t bring an outbreak under control — they reduce flight pressure and slow new colonization, but biological or chemical controls do the actual reduction. Use mass trapping as part of an IPM program, not as a stand-alone strategy.

Placement and orientation

Hang vertical traps just above the canopy for flying adults — whitefly, thrips, winged aphids, leafminer. Use horizontal orientation at media level for fungus gnat and shore fly emergence. Distribute traps evenly across the crop with extra coverage at known hot spots, doorways, vents, and shipping zones where pests enter.

Pull traps during biocontrol releases

Yellow sticky traps catch beneficials too — parasitic wasps (Aphidius, Encarsia, Eretmocerus, Trichogramma), predatory midges (Aphidoletes, Feltiella), and beetles (Cryptolaemus). Remove or reduce yellow traps for the first 2–3 days after a beneficial release, or restrict yellow traps to 2 days per week during active release windows. Blue traps generally don’t catch Aphidius and most other parasitoids, so they can stay up through thrips monitoring while a parasitoid program runs.

Monitoring & advisories

Monitor for

Trend, not absolute count. Rising weekly counts call for action; flat or falling counts confirm the current program is working.
Species composition. ID by morphology under a 10× hand lens or send the trap to extension for confirmation. Whitefly, thrips, and fungus gnat each look distinct on the card.
Geographic clustering. If most catches concentrate near a doorway or vent, you have an entry point to address. If they spread across the crop, the population is established.
New pest introductions. Sticky traps are usually how a previously unrecorded pest shows up in the data first.
Beneficial captures on yellow traps after a release — if you’re catching the predator you just paid for, reduce yellow-trap exposure during the establishment window.

Advisories

Sticky traps monitor; they don’t treat. Pair trap counts with biological controls, cultural sanitation, and (where needed) selective chemicals.
Replace traps on a fixed schedule even when they look uncrowded — aging adhesive captures fewer insects, biasing the count downward.
Hot weather softens adhesive enough that insects can wriggle free. Replace more often during summer or in unvented houses.
Yellow traps will catch flying beneficials. Pull them or restrict to 2 days per week during active biocontrol releases.
Even high counts don’t automatically mean action is needed. UC IPM is explicit: combine traps with direct plant inspection to determine the action threshold.

Color × pest selection chart

Pest	Best color	Orientation	Notes
Whitefly (Bemisia, Trialeurodes) preventive	Yellow	Vertical, just above canopy	Pull yellow during Encarsia or Eretmocerus releases.
Thrips (Frankliniella, Thrips spp.) preventive	Blue (preferred) or yellow	Vertical at canopy	Blue protects Aphidius parasitoids. White preferred for Frankliniella if available.
Fungus gnats preventive	Yellow	Vertical at pot rim, or horizontal at media level	Combine with NEMAforce SF or DALOTIAforce for control.
Shore flies preventive	Yellow	Vertical or horizontal near algae substrates	Pair with NEMAforce SC for shore fly larvae control.
Winged aphids preventive	Yellow	Vertical at canopy	Monitor wing-form aphids only; wingless colonies stay on plants.
Leafminer adults preventive	Yellow	Vertical at canopy	Time biocontrol releases (Diglyphus) to peak adult capture.
Scale crawlers active	Yellow	Vertical at branch level	Monitoring window is narrow — check daily during crawler emergence.
Monitor density: 1 trap per 250 sq. ft. in mixed greenhouses, or 1 per 1,000 sq. ft. in large monoculture houses. Replace on a fixed schedule (weekly typical).

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Cannabis Alert

Cannabis growers typically need higher trap density and more frequent replacement than the conventional schedule above. Contact us for cannabis-specific scouting program guidance.

Building a sticky-trap scouting program

The trap is one piece. A working monitoring program needs four elements running together.

Map

Place + label every trap location

Count

Same day every week, by species

Chart

Weekly trend per pest per zone

Act

Release, treat, or sanitize on the trend

Disclosures

Tool category. Sticky traps are a scouting and monitoring tool. They are not a stand-alone control method for most pest situations. Combine with biological controls (predators, parasitoids, beneficial nematodes), cultural sanitation, and selective chemicals where appropriate.

Beneficials caution. Yellow sticky traps will catch flying beneficials including parasitic wasps, predatory midges, and lady beetles. Reduce or remove yellow trap exposure during active beneficial release windows to avoid capturing the predator you just paid for. Blue traps generally don’t catch Aphidius and most parasitoids.