Verticillium Wilt

Verticillium wilt strikes from the ground up, often catching you by surprise. You'll notice leaves on just one side of a maple, cherry, or blueberry beginning to yellow and wilt, sometimes while the opposite side remains vigorous. As the disease progresses, entire branches die back, and the characteristic symptom appears: vascular streaking inside the stem, visible when you cut through wood showing brown or purple discoloration in the water-conducting tissue. In Western Washington, this disease commonly emerges in maples and blueberries after the plant has been in the ground for a few years, making established plantings vulnerable when conditions turn wet.

Verticillium wilt is caused by a soilborne fungus that nearly impossible to eradicate once established in your soil. The pathogen persists for years as microsclerotia and can survive in susceptible weeds around your property. Once in the plant's vascular system, it blocks water movement and produces toxins that trigger wilting. There is no cure for infected plants. Your management strategy must center on prevention: plant only healthy, certified stock; avoid planting susceptible crops in previously infested soil; control weeds aggressively; and keep nitrogen fertility at normal levels only, as excessive nitrogen promotes disease severity. If a plant develops symptoms, remove it promptly to reduce spore production in that location.