What is Verticillium wilt?
Verticillium wilt is a fungal disease known to affect a wide range of plants, from trees and shrubs to fruit and vegetables. More than three hundred plant genus can be affected. While infection can occur all year round, symptoms are most apparent during spring and summer.
Verticillium wilt lives in the soil and enters plants through their roots. The infection travels through, and blocks, the xylem plant tissues, which are responsible for transporting water around the plant. Unable to hydrate itself, the plant wilts and dies back. As well as blocking the xylem, the fungus spreads toxins through the plant.
Verticillium wilt can persist in the soil for many years.
How to identify Verticillium wilt
Symptoms develop rapidly in dry, hot weather when the plant is growing rapidly and needs lots of water. Symptoms of verticillium wilt include:
- Yellowing, dying, or shrivelling leaves, starting on the older growth
- Dieback of branches
- Stunted or distorted growth, which causes reduced yield on fruit crops
- Sudden wilting in hot weather, sometimes followed by recovery when conditions turn cool and wet
- Cutting through an infected stem or branch reveals dark staining of the tissues
Trees and plants commonly affected
Verticillium wilt affects a wide range of plants but those known to be particularly susceptible include Berberis, chrysanthemum, elder (Sambucus), Indian bean tree (Catalpa), Judas tree (Cercis), maple (Acer), smoke bush (Cotinus), stag’s horn sumach (Rhus), and strawberry.
How to get rid of Verticillium wilt
Like many diseases, there is no cure or chemical control for verticillium wilt, so prevention and maintaining healthy plants is particularly important. Here are our tips for preventing Verticillium wilt:
- Only buy healthy plants from a reputable source: the disease is transmitted on infected soil
- Avoid composting any diseased plant material. It's safe to dispose of in garden waste collections as material composted on a large scale reaches high temperatures that kill pathogens
- Avoid moving soil from around infected plants
- Clean pruning tools with a garden disinfectant before using on other plants
- Grow plants that are known to have good natural resistance. Trees include beech (Fagus), birch (Betula pendula), eucalyptus, hawthorn (Crataegus), holly (Ilex), hornbeam (Carpinus), and willow (Salix). Plant groups that are not affected by verticillium wilt include conifers, ornamental grasses, and bulbs
- Keep your soil in good condition by mulching with organic matter such as garden compost or well-rotted manure
- Improve drainage where the soil tends to become waterlogged
- Weed regularly, as weeds may host the disease without showing symptoms