Potato wilting
There are 4 common causes, and they need completely different responses — so working out which one you have matters more than treating quickly.
3 of them can kill the plant. Rule those out first.
Check these two things first
- Push a finger into the soil, two knuckles deep. Wet soil plus a wilting plant means too much water, not too little — and it is the commonest reason a plant is dying. Dry soil plus crisp leaves means the opposite. The leaves look nearly identical either way, so the soil is what tells you.
- Turn a damaged leaf over. Half of all diagnoses live on the underside: fuzz means downy mildew, fine webbing means spider mites, clusters of insects mean aphids. Nothing on the top of a leaf is as informative.
Most garden problems are cosmetic and resolve without treatment. Reach for a spray last, not first.
The 4 causes, and how to tell them apart
1.Bacterial Wilt
Act nowBacterial disease
Individual leaves wilt suddenly and dramatically while still fully green, then whole runners, then the plant. No yellowing, no spots — just collapse. Cut the stem, touch the two cut faces together and pull them slowly apart: sticky white threads stretch between them.
How to know it is this one
The string test: cut stem, press the faces together, pull apart. Sticky threads confirm it.
2.Late Blight
Act nowFungal disease
Large irregular blotches that look greasy or water-soaked, grey-green at first and turning brown-black. In humid weather a fine white fuzz appears on the underside at the edge of each lesion. Fruit develops firm, greasy brown patches.
How to know it is this one
Lesions look wet or greasy rather than dry and crisp, even in dry weather.
3.Verticillium Wilt
Act nowFungal disease
Yellow wedges spreading inward from the leaf edges, often forming a V shape pointing at the midrib. Lower leaves go first. Cutting the stem shows brown discolouration in the vascular ring, usually lighter than fusarium's.
How to know it is this one
V-shaped yellow wedges at the leaf margins.
4.Underwatering
TreatableGrowing conditions
Drooping leaves that feel dry and papery, crisp brown edges and tips, and soil that has shrunk away from the sides of the pot. The whole plant looks deflated, and lower leaves go crisp and yellow before dropping.
How to know it is this one
Leaves dry and crisp rather than soft and limp.
Still not sure?
The diagnostic key adds two more questions — which part is affected and where the trouble started — and those usually settle it.
Run the diagnostic key