BioWiki / Environment
Ventilation & air movement — IPM driver (protected crops)
Ventilation & air movement — IPM driver (protected crops)
Summary
Air movement governs microclimate pockets. Poor ventilation creates hotspot geography where pests establish out of sight and biocontrol distribution becomes uneven.
What this driver controls
- Boundary layer thickness → leaf temperature + transpiration uniformity
- Local RH pockets (especially in dense canopy)
- Dispersal and search efficiency of beneficials
- Hotspot formation vs whole-crop pressure
Pest fingerprints
Thrips
- Often distributed, but can concentrate around flowers and sheltered zones.
- Poor airflow can increase local stress pockets and uneven control.
Spider mite
- Hotspots form in warm, dry microclimate zones (edges, heaters, high VPD pockets).
- Ventilation that creates uneven dryness can worsen “structural” risk.
Aphids
- Colonies cluster on flush; microclimate affects how quickly clusters expand and how detectable they are.
- Dense canopy can hide colonies until expansion is advanced.
Beneficial stability / failure modes
- Predators/parasitoids may not cover evenly if airflow/canopy structure creates barriers.
- Uneven microclimate → uneven plant growth → uneven susceptibility → patchy control.
Monitoring signals
- Hotspot maps from scouting (where do pests repeatedly start?)
- Canopy density and “dead zones” (stagnant corners, under benches, near screens)
- Uneven leaf temperature/RH if sensors are available
Stabilising actions
- Use airflow to reduce boundary layer and prevent humid pockets without over-drying.
- Manage canopy structure (spacing, pruning) to reduce hidden reservoir zones.
- If hotspots are consistent, bias monitoring and pre-emptive releases into those zones.