Verticillium Wilt Is Killing My Strawberry Plants

Strawberry plants that begin wilting during dry or warm weather — starting with the outer leaves, progressing to the whole plant — and do not recover with watering, and on inspection show brown discolouration in the vascular tissue of the crown and leaf stalks (visible as a brown staining inside the stem when cut) may have verticillium wilt. This soil-borne disease is caused by the fungus Verticillium dahliae, which colonises the vascular system of the plant and prevents water and nutrient movement from roots to leaves. It is a serious disease that can persist in soil for many years.

How to identify verticillium wilt

The key diagnostic is vascular browning inside the crown and petioles (leaf stems). Pull a wilting plant, cut through the crown horizontally, and look for a tan or brown ring in the tissue (the vascular ring), instead of the healthy cream-white. This internal browning, combined with wilting that does not respond to watering, strongly indicates verticillium wilt. The disease typically appears first in hot weather (June onward) when transpiration demand is high and the restricted water flow becomes critical. Individual plants die while neighbours remain healthy initially.

Why it is linked to previous crops

Verticillium dahliae has a very wide host range — potatoes, tomatoes, peppers, aubergine, raspberries, and many other vegetables are susceptible. Growing strawberries after any of these crops on the same ground introduces the risk of high Verticillium soil populations. The fungus persists in soil as microsclerotia for many years even without a host plant. Rotation to strawberries after brassicas or alliums (which are not hosts) significantly reduces risk. Avoid planting strawberries in ground that grew potatoes or tomatoes in the previous four years if verticillium wilt has been a problem.

Management

There is no cure for infected plants. Remove and destroy them and do not replant strawberries in the same bed for at least five to seven years. Choose new planting sites on ground with a different cropping history. Use certified virus- and disease-free planting stock from reputable suppliers; runners taken from gardens with unknown disease history are a common route for disease introduction. Some modern strawberry varieties have improved tolerance to Verticillium — check cultivar descriptions when selecting plants.