Plant problems · Pests · Any stage · Act this week
Thrips
What you see
- Silvery, shiny scratches on leaves
- Tiny black dots (droppings) on the silver patches
- Very small, thin insects that move fast on leaves
Why it happens
Thrips scrape leaf surfaces and drink the sap. They come in from outside, often on new plants.
What to do
- Hang blue sticky traps to monitor and catch adults
- Use predatory mites (Amblyseius cucumeris or swirskii) or spinosad based products in veg
- Remove the worst leaves
Next time
- Quarantine new plants
- Keep the grow space clean
Easy to confuse with
- Spider mites: Tiny white or yellow dots on the top of leaves
- Septoria leaf spot: Round yellow spots on lower leaves that turn brown with a yellow halo
Not sure?
Take a photo of a silvery patch on a leaf, very close and ask the Grow Doctor, or send it to the grow companion on Telegram.