Verticillium Wilt
Act nowFungal disease · does not spread
Verticillium is fusarium's cool-weather counterpart, and it attacks a much wider range of plants including maples and roses. On a shade tree it causes branches to die back one at a time over several seasons. Like fusarium there is no cure, and the fungus persists in soil for a very long time.
What it looks like
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 confirm it
- V-shaped yellow wedges at the leaf margins.
- Prefers cooler soil, so it often shows in spring and early summer.
- Brown streaking in the stem's vascular ring.
- On trees, whole branches die back one at a time rather than the crown thinning evenly.
What to do
- 1On vegetables, remove and bin the plant and grow something unrelated in that spot.
- 2On a tree, prune out dead branches, water deeply in dry spells, and avoid feeding heavily with nitrogen — trees often live with it for years.
- 3Do not replant susceptible species in the same soil.
What it gets confused with
One observation settles each of these.
Fusarium prefers warm soil and often yellows one whole side; verticillium prefers cool soil and makes V-shaped edge wedges. Management is the same either way.
Preventing it next time
- Choose resistant varieties — the V code on a tomato label.
- Rotate with grasses and corn, which are not hosts.
- Keep trees vigorous with mulch and deep watering rather than heavy feeding.
Plants affected
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.