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IPM Risk Engine - Protected Crops
IPM Risk Engine - Protected Crops
Spider Mite · Thrips · Aphids Strawberry · Ornamentals · Protected Edibles (UK)
Purpose
This document formalises the Phase 1 IPM Risk Engine for protected cropping systems.
It translates:
- Environmental drivers
- Crop susceptibility
- Pest biological behaviour
into structured risk phase states.
The objective is to identify amplification windows before visible outbreak.
Read alongside: - Environmental Drivers Hub - Pest Pressure Hub - Individual pest pages - Crop-specific IPM programmes
Core Risk Model
Risk = Environmental Suitability × Crop Susceptibility × Predator Stability
Outbreaks represent phase transitions, not isolated events.
Monitoring without environmental interpretation is reactive. Environmental trend + crop stage = predictive pressure.
Destabilisation Types (Doctrine Layer)
| Pest | Destabilisation Type |
|---|---|
| Spider mite | Dry Heat Amplifier |
| Thrips | Flowering Accelerator |
| Aphids | Nutrient Surge Responder |
Spider Mite
Species anchor: - Tetranychus urticae
Environmental Phase Bands
| Temperature | RH | Crop Stage | Risk Level | Phase | Action Window |
|---|---|---|---|---|---|
| <18C | Any | Any | Low | Suppressed | Monitor only |
| 18-22C | >65% | Vegetative | Low-Moderate | Stable | Check hotspots |
| 20-24C | 55-65% | Fruiting / Flowering | Rising | Instability forming | Introduce preventative predators |
| 22-26C | <60% | Fruiting | High | Amplification onset | Immediate intervention |
| >26C | <55% | Fruiting | Very High | Amplification phase | Curative predator + humidity correction |
Crop Sensitivity Modifier
| Crop | Modifier |
|---|---|
| Cucumbers | +1 risk tier |
| Strawberry (fruiting) | +1 risk tier |
| Basil | +1 risk tier |
| Tomatoes | Neutral |
| Bedding ornamentals | Variable |
Escalation Triggers
Escalate one risk tier if:
- 5-day upward temperature trend
- Canopy RH below 60%
- No predatory mites established
- Crop entering peak fruiting
Spider mite is a phase-transition pest in dry heat systems.
Thrips
Species anchors: - Frankliniella occidentalis - Thrips tabaci
Environmental Phase Bands
| Temperature | Flowering Status | RH | Risk Level | Phase | Action Window |
|---|---|---|---|---|---|
| <16C | Any | Any | Low | Suppressed | Monitor |
| 16-20C | Pre-flower | Any | Moderate | Stable | Early predator establishment |
| 18-24C | Flowering | Any | High | Acceleration | Preventative Orius introduction |
| 22-26C | Flowering | <65% | Very High | Amplification | Immediate predator + monitoring increase |
| >26C | Heavy flowering | Any | Extreme | Rapid cycling | Dual predator strategy |
Crop Sensitivity Modifier
| Crop | Modifier |
|---|---|
| Flowering ornamentals | +1 |
| Strawberry (flowering) | +1 |
| Cucumbers (flowering) | +1 |
| Tomatoes | Neutral |
| Herbs | Neutral |
Escalation Triggers
Escalate one risk tier if:
- Flower initiation detected
- Pollen availability increasing
- Warm stable conditions for 5+ days
- Orius not yet established
Thrips are a flowering-accelerated destabiliser.
Aphids
Species anchors: - Myzus persicae - Aphis gossypii
Environmental Phase Bands
| Temperature | Growth Type | RH | Risk Level | Phase | Action Window |
|---|---|---|---|---|---|
| <12C | Any | Any | Low | Suppressed | Monitor |
| 12-18C | Soft vegetative flush | 60-75% | Moderate | Establishment | Preventative parasitoids |
| 15-22C | Soft growth | 65-80% | High | Expansion | Immediate parasitoid release |
| 18-24C | High nitrogen feeding | 60-75% | Very High | Rapid colonisation | Curative + banker reinforcement |
| >25C | Any | Low RH | Variable | Stress-modified | Monitor closely |
Crop Sensitivity Modifier
| Crop | Modifier |
|---|---|
| Soft vegetative ornamentals | +1 |
| Strawberry (vegetative flush) | +1 |
| Cucumbers | +1 |
| Tomatoes | Neutral |
| Herbs | Neutral |
Escalation Triggers
Escalate one risk tier if:
- High nitrogen feeding phase
- Rapid vegetative flush
- Predator absence
- Increasing RH stability
Aphids are a nutrient surge responder.
System-Level Escalation Rules
If TWO of the following are true, escalate one tier:
- Predator not established
- 5-day temperature upward trend
- Crop entering susceptible stage
- High nitrogen feeding
- Canopy RH instability
If THREE are true, assume amplification within 7-10 days.
Temperature Tier Definitions
| Band | Interpretation |
|---|---|
| <15C | Suppressed biological development |
| 15-20C | Stable development |
| 20-24C | Rising reproductive rate |
| 24-28C | Amplification band |
| >28C | Stress-modified behaviour |
Intended Use
This matrix is:
- A grower decision-support framework
- A doctrine layer for Biopredator
- A precursor to dynamic risk modelling
- Compatible with future integration into Agrinomy weather uploads
It is not a chemical threshold chart. It is a systems destabilisation detector.