Lettuce IPM Module
Practical IPM plan for lettuce covering protected lettuce, outdoor lettuce, hydroponics and baby leaf systems.
Main focus: aphids, sciarid fly, shore fly, caterpillars, mildew, Botrytis and hygiene.
Main pest risks
| Pest | Risk | Main trigger |
|---|---|---|
| Aphids | High | Soft rapid growth |
| Sciarid fly | Moderate | Wet substrate |
| Shore fly | Moderate | Algae and wet media |
| Caterpillars | Moderate | Outdoor migration |
| Thrips | Moderate | Warm protected crops |
| Mildew | High | Humidity and airflow |
| Botrytis | Moderate | Dense humid crops |
Monitoring plan
Best practical rule: inspect the heart leaves and undersides weekly. Aphids hidden deep inside heads are often missed until harvest.
| Area | What to inspect |
|---|---|
| Heart leaves | Aphids and feeding |
| Lower leaves | Botrytis and mildew |
| Propagation trays | Sciarid fly |
| Wet zones | Algae and shore fly |
| Outdoor edges | Caterpillar entry |
Environmental risk
| Condition | Likely issue |
|---|---|
| Humid stagnant air | Mildew and Botrytis |
| Excess nitrogen | Soft aphid-prone growth |
| Wet substrate | Sciarid fly |
| Algae build-up | Shore fly |
| Overcrowding | Hidden disease pockets |
Disease pressure
Lettuce disease risk increases sharply when: - crops remain wet for prolonged periods - airflow is poor - crops are overly dense - old leaves are not removed
Useful practices: - maintain airflow - reduce humidity spikes - remove old leaves - avoid overwatering late in the day
Key message
Lettuce IPM depends heavily on hygiene, airflow and prevention of early aphid establishment.