Spider mites on zucchini
The two-spotted spider mite feeds on courgette leaf undersides in hot, dry summers. Leaves first develop pale stippling, then turn rusty and shrivel, and cropping stops abruptly.
Symptom photos
Symptoms
- Fine, pale stippling and mottling on the leaf blade
- Delicate webbing on leaf undersides and in the vein axils
- Rusty-brown, drying leaves
- Very small, moving mites visible with a hand lens
- Leaves drying out starting with the oldest
What it does to the crop
- Leaf loss and sunscald on the fruit
- Cropping ending prematurely
- Small, poorly developed fruit
- Very rapid breeding in the heat
What encourages it
- Heat above 25°C and low humidity
- Drought and water stress
- Growing under cover without misting
- Too much nitrogen
Prevention
- Water regularly and mist during hot spells
- Check leaf undersides from June
- Introduce predatory mites under cover
- Remove the worst-affected leaves
- Clear crop debris after the season
⚠️ Before you reach for a spray
This atlas is informational and still growing — different diseases can look almost identical. Confirm the diagnosis and read the product label before applying any plant protection product. If you are unsure, ask your local extension or advisory service.
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