# Irregular dead or bleached patches after spraying: likely causes and fixes

> Irregular dead or bleached patches after spraying on cannabis is most often Spray or foliar burn (pesticide, oil, soap, foliar feed). How to tell them apart, the fix for each and what recovery looks like.

Also called: spray burn, leaves burnt after spraying, foliar burn, droplet burn spots, neem burn, white patches after spray.

Run the checker with this sign: https://genetixbay.com/knowledge/diagnose/?at=whole&s=random-dead-patches

## Likely causes, most likely first

### Spray or foliar burn (pesticide, oil, soap, foliar feed) (Likely)

- Kind: Physical damage; urgency: Low urgency
- Fix: Stop spraying; rinse residue off with plain water at lights-off if damage is fresh. In future spray only at lights-off or with lights raised, test one leaf 24-48 h first, never mix sulfur with oils, and never spray buds.
- Recovery: No new damage on leaves that grow after the spray.
- Confirm: Magnifier check of leaf undersides and new growth: Use a 10-20x loupe for spider mites, thrips, aphids and whiteflies, and a 30-60x lens or clip-on phone macro for broad and russet mites. Check the undersides of 10 affected leaves across several plants and the newest shoot tips, in white light. Look for moving dots, eggs, shed skins, webbing, slender insects with black specks, and glassy specks on new growth.
- Confirm: Wipe test for white coatings: Wipe a white spot gently with a damp finger or cotton bud and mark the leaf. Powdery mildew comes off as powder and reappears in 2-5 days on the same and nearby leaves; spray or hard-water residue wipes off and stays gone; trichomes and thrips scars do not wipe off. Wash hands afterwards: spores travel on fingers.
- Article: [What can I safely spray on plants in flower?](https://genetixbay.com/knowledge/answers/what-can-i-spray-in-flower.md)

## Note

Guidance, not a guarantee. The checker weighs common causes against what you tell it; confirm with the tests before you treat, change one thing at a time and watch the new growth.