🧰 What You'll Need
Yellow sticky cardsPetroleum jellyCardboardWire or twist ties
📋 Steps
1
Choose the right color for your target pest
Yellow: fungus gnats, whiteflies, aphids, thrips, shore flies, and most flying insects. Blue: western flower thrips (more attracted to blue). White: some leafminers. Most pest monitoring uses yellow.
2
DIY version with petroleum jelly
Apply a thin layer of petroleum jelly to bright yellow cardboard. Replace when surface is covered. Works exactly the same as commercial traps at a fraction of the cost.
3
Position at canopy level for flying insects
Place traps at the top of plant canopy for whiteflies and aphids; near soil surface for fungus gnats; at entry points (door frames, window sills) for general monitoring.
4
Count and record insects weekly
The value of sticky traps is the trend data. Record pest counts weekly. A sudden 5x increase in fungus gnats signals a new overwatered plant. Rising whitefly counts signal early population growth.
5
Place traps at suspected entry points
For indoor flying pests, place traps near windows, doors, and any point where outside air enters. This identifies primary entry vectors.
💡 Pro Tips
- Change traps weekly — a covered trap loses effectiveness and accurate counting becomes impossible
- Yellow traps also catch beneficial insects including parasitic wasps — monitor for beneficial presence too
- Record catch data with dates — this creates a pest pressure history for your property that improves treatment timing over time