University of Maryland Extension

Verticillium Wilt

early leaf symtoms of verticillium wilt
Early symptoms of verticillium wilt includes yellowing or off color of scattered branches

Verticillium Wilt is a common disease problem occurring on shrubs caused by the common soil fungus Verticillium spp. Some commonly grown shrubs that are susceptible to verticillium wilt include azalea, daphne, hibiscus, osmanthus, lilac, photinia, rose, spirea, viburnum, and weigela. 

young tree infected with verticillium wilt disease
Young tree infected with verticillium wilt

Early symptoms usually start as a yellowing or off color of scattered branches. These symptoms are usually followed by wilting and sudden dieback of infected limbs especially during drought or in the heat of summer. Eventually the entire plant may wilt and die, however established shrubs may live for years with dieback symptoms before succumbing. Sunken cankers with bark splitting may develop on infected limbs. A partial list of resistant shrubs includes dogwood, firethorn, flowering quince, holly, and rhododendron.

branch with verticillium
Cross-section of branch showing discoloration of vascular tissue from verticillium

Some cultural practices can help to prolong the life of infected plants in the landscape. Prune out wilted and dead branches. Avoid high nitrogen fertilizers. Fertilize in fall or late winter with a balanced fertilizer containing an N:P:K ratio of 2:1:2. Water during drought and use mulches to conserve water and control weeds.

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