Divisi
Tobacco angular leaf spot
Pseudomonas syringae pv. tabaci · Bacterial
A warm-weather bacterial leaf disease of tobacco. It makes angular (vein-bounded) dead spots, often ringed by a wide yellow halo (the 'wildfire' form), that riddle the marketable leaf and let the plant lose grade and weight.
Why it matters
Angular leaf spot can strip up to 40% of the value off a crop. The bacteria pit the leaf with dead, angular holes and yellow halos right on the part you sell — the cured leaf loses grade, weight and price. It rides in on splashing rain and on your own hands and tools when you work the crop wet, so it can race through a field in a warm, wet week. There is no spray that cures a spotted leaf — you win by keeping it out and keeping clean leaves protected.
When to act
First small, angular (straight-edged) water-soaked spots on the lower leaves, especially after warm wet weather — act at once; a bactericide only protects clean leaves, so start before it climbs into the crop.
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full tobacco angular leaf spot field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to tobacco angular leaf spot — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify tobacco angular leaf spot?
The key sign — angular spots: small water-soaked (greasy, see-through) spots on the leaf that dry to brown or tan dead patches with straight edges — they look angular, boxed-in by the leaf veins, not round. That vein-bounded, angular shape is the giveaway.
When should I take action against tobacco angular leaf spot?
First small, angular (straight-edged) water-soaked spots on the lower leaves, especially after warm wet weather — act at once; a bactericide only protects clean leaves, so start before it climbs into the crop.
How do I control tobacco angular leaf spot?
Prevent — start clean in the seedbed: use clean/certified seed and a clean seedbed away from last year's tobacco. Never work seedlings or plants while they are wet, and do not water from overhead late in the day — water the soil, not the leaves, so foliage dries fast. Handle the crop as little as possible when damp.
Which crops does tobacco angular leaf spot affect?
Among the crops covered here: Tobacco.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
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