Verticillium Wilt is a fungal disease affecting over 400 species of plants. It is spread by infection through wounds, which can occur naturally via contaminated soil and wind, or artificially, such as through unsanitary pruning practices between infected plants. Verticillium Wilt kills by interrupting plant vascular systems, thereby preventing the transport of food, water and nutrients.
Symptoms of Verticillium Wilt are often most noticeable during the summer months. Affected plants will exhibit signs such as one side of the plant declining suddenly, unusually heavy seed crops, branch dieback, abnormal leaf drop or red or yellow discoloration of leaves between veins. Streaking of branch and/or trunk tissues is often a sign of Verticillium infection (see photo). Streaking may be seen under the bark of infected branches or in cross sections of larger branch or trunk tissue.
Because plant stress contributes to susceptibility, prevention includes following a regular water and fertilizer schedule to keep plants healthy. Always sanitize pruning tools between plants.
This disease can be controlled, but not eliminated, by removing and disposing of affected branches, leaves, etc. The only way to eliminate the infection is to remove and discard infected plants. Because Verticillium Wilt can live in the soil for many years, infected plants should not be composted. Never plant a susceptible plant in an area where Verticillium Wilt is present. Below are listed susceptible and resistant plants.
Plants Susceptible to Verticillium
Aspen, Ash, Barberry, Buckeye, Catalpa, Cherry, Currant, Elm, Goldenrain Tree, Honeysuckle, Horsechestnut, Kentucky Coffee Tree, Lilac, Locust, Privet, Magnolia, Maple, Quince, Raspberry, Redbud, Rose, Russian Olice, Sassafras, Serviceberry, Smoketree, Strawberry, Sumac, Tree Of Heaven, Tomato, Tulip Tree, Tupelo, Viburnum, Walnut, Weigela, Yellowwood
Plants Resistant to Verticillium
Apple, Beech, Birch, Boxwood, Ceanothus, Conifers, Crabapple, Crape Myrtle, Dogwood, Enkianthus, European Mountain Ash, Fig, Fir, Firethorn, Ginkgo, Hackberry, Hawthorn, Hemlock, Hickory, Hinoki, Holly, Honeylocust, Hornbeam, Japanese Snowbell, Japanese Stewartia, Juniper, Katsura Tree, Larch, Linden, London Planetree, Ninebark, Oak, Pawpaw, Pear, Parrotia, Pine, Poplar, Rhododendron, Serviceberry, Spruce, Sweet Gum, Sycamore, Willow, Witch Hazel, Yew, Zelkova