Mottled mosaic or yellow streaks, distorted leaves
Irregular light and dark green patches, often with leaf distortion; may be on one plant only..
- Also called
- mosaic pattern on leaves
- yellow streaks
- mottled leaves
- blotchy yellow pattern
- virus looking leaves
Likely causes, most likely first
Ranked for this sign on its own. Your stage, medium and readings change the order, so run the checker for your plant.
PossiblePlant virus (e.g. beet curly top, lettuce chlorosis virus)
Fix: No cure: remove the plant. Control insect vectors (leafhoppers outdoors for curly top; whiteflies for some others) and test clone sources.
Recovery: No new symptomatic plants over the next 2-4 weeks.
How to confirm it
- Send a sample to a plant diagnostic lab. For rots, wilts, leaf spots and viruses you can't separate by eye, send a fresh sample (whole plant with roots or a wilting branch with healthy and diseased tissue) in a sealed bag to a university or commercial plant diagnostic clinic. Results in days to 2 weeks.
- 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.
Less likelyHop latent viroid (dudding)
Fix: No cure in a plant. Test mothers (roots and leaves) by RT-PCR or RT-qPCR, discard positives, disinfect tools with 10% bleach or heat (alcohol and peroxide don't inactivate it), and use meristem tissue culture to rescue valuable genetics. Don't take cuttings from stunted plants.
Recovery: Negative tests on new mothers; no more duds in the next cycle.
How to confirm it
- Lab test for hop latent viroid (RT-PCR or RT-qPCR). Send root and leaf samples (roots detect HLVd earlier in young plants) to a lab offering HLVd RT-PCR or RT-qPCR. Test mother plants and any stunted plant among healthy siblings. A positive plant cannot be cured; tissue culture of meristem tips can rescue genetics.
- Compare with siblings or the same cut. Put the affected plant beside siblings or clones of the same cut in the same conditions. A trait shared by all of a cultivar (purple stems, foxtailing, pale colour) is genetic; a problem on one plant points to its roots, a virus or its genetics; a problem on every cultivar points to the environment or feed.
Less likelyHerbicide drift or residue
Fix: Outdoors or with contaminated compost, manure or straw (persistent herbicide residues). Remove the source, repot into clean media; new growth may normalise slowly. Cannabis-specific symptom descriptions are scarce.
Recovery: New growth normalises over 2-4 weeks after the source is removed.
How to confirm it
- 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.
- Send a sample to a plant diagnostic lab. For rots, wilts, leaf spots and viruses you can't separate by eye, send a fresh sample (whole plant with roots or a wilting branch with healthy and diseased tissue) in a sealed bag to a university or commercial plant diagnostic clinic. Results in days to 2 weeks.
Look for
Patchy light/dark green mosaic not following veins or leaf age; distorted, puckered blades..
The full guide: Hop latent viroid (HLVd, 'dudding') and other cannabis viruses
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.
