What it looks like
Twigs and branches die back from the tip downward. The dead portion turns straw-coloured or dark, and the boundary between living and dead tissue is usually sharp. Flowers and young fruit drop before they develop.
In a bad year the plant is progressively stripped from the top, and the yield loss is quiet — there is no dramatic collapse, just a crop that never fills.
The connection people miss
Die-back is caused by the same Colletotrichum that causes fruit anthracnose. So a programme aimed only at fruit rot leaves the stem infections producing spores continuously, and vice versa.
Treat them as one disease, because they are.
Management
- Resistant or tolerant varieties where available for your area.
- Treated seed, since it is seed-borne.
- Protectant cover through wet weather, from flowering onward, rotating the FRAC group.
- Prune out and remove dead twigs rather than leaving them on the plant, which is where the spores come from.
- Adequate spacing and staking, for airflow.
- Balanced nutrition. A crop pushed hard on nitrogen is softer and more susceptible; potassium and calcium sufficiency measurably help.
Not everything that dies back is die-back
Wilt — the whole plant collapses, often on one side first, and the stem is discoloured internally near the base. Soil-borne, and no spray reaches it.
Bacterial wilt — sudden collapse with green leaves still attached, and a milky ooze when a cut stem is stood in clear water. That test takes two minutes and settles it.
Water stress or salinity — patchy, follows the ground rather than the planting, and worse in the low or the high spots.
Root damage or nematodes — pull the plant and look at the roots before assuming anything about the top.
The field-level answer
Chilli after chilli after chilli builds all of these. A cereal in the rotation, Trichoderma enriched into farmyard manure at planting, and drainage are worth more over three seasons than any spray programme.
Read the label and the leaflet on the pack before use. The approved crops, dose and waiting period printed there are what count.
