Arthropod pests
Whiteflies
Whiteflies are small sap-feeding insects whose eggs and immature stages occur primarily on leaf undersides. Adults may disperse when foliage is disturbed, while immature stages can be overlooked without deliberate inspection.
What to look for
- Tiny pale adults lifting from foliage when plants are disturbed
- Eggs and flattened immature stages on leaf undersides
- Localized chlorosis or reduced vigor under heavier pressure
- Sticky honeydew or secondary sooty growth where populations are substantial
Important look-alikes
- Fungus gnat adults near the substrate
- Small pale moths or other flying insects
- Non-pest white residue on leaf undersides
- General chlorosis from root-zone or nutritional stress
How to confirm
- Inspect leaf undersides with magnification
- Use sticky cards to monitor flying adults while still inspecting plants
- Record life stages separately
- Map hotspots rather than relying on whole-room presence or absence
Management principles
- Reduce movement from infested to clean zones
- Remove heavily infested plant material when appropriate
- Use life-stage-aware IPM and compatible biological controls where applicable
- Re-scout after intervention to confirm population trend
Prevention
- Inspect incoming plants before release into production
- Maintain weed and volunteer-plant sanitation
- Use exclusion screening only with ventilation tradeoffs understood
- Keep scouting records from the start of the crop
Visual study guide
- Adult and immature whitefly comparison
- Leaf-underside life-stage plate
- Whitefly versus fungus-gnat comparison
- Greenhouse hotspot map