Dr. Phyto
Alternaria leaf spot
Alternaria alternata
Symptoms
Dark brown spots with concentric rings (target-board pattern, diagnostic), yellow halos around spots, severely infected leaves yellow + drop, lower + older leaves attacked first, white-to-grey sporulation in lesion centers under humid conditions.
Plants affected
Treatment
Dr. Phyto builds a dated, step-by-step treatment plan with country-approved products — start a free diagnosis to get yours.
Common questions
- How do I recognise Alternaria leaf spot on tobacco?
- Dark brown spots with concentric rings (target-board pattern, diagnostic), yellow halos around spots, severely infected leaves yellow + drop, lower + older leaves attacked first, white-to-grey sporulation in lesion centers under humid conditions.
- Do I have to report Alternaria leaf spot?
- No. Alternaria leaf spot is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.
- How is Alternaria leaf spot treated?
- Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.
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