Goldleaf Elder Shrub Fungal Diseases
The gold leaf elder shrub, or Sambucus canadensis aurea, is a United States native that is commonly referred to as the American elder or golden elder. This small shrub reaches mature heights up to 13 feet with a spread up to 10 feet. This deciduous shrub produces small, yellow foliage and blooms with showy, white flower clusters. It is an adaptable tree that thrives in most well-drained soils and is an appropriate selection for landscaping, patios and screening hedges. Hardy in U.S. Department of Agriculture plant hardiness zones 4 through 11, the golden elder is mostly resistant to disease but is susceptible to several fungal diseases.
Verticillium wilt is a destructive disease of the golden elder. This soil-borne fungal disease can live for years in the soil before it infects this shrub,according to Purdue University Cooperative Extension. Entering through the elder’s root system, the disease attacks the shrub’s vascular system and prevents the system from successfully passing nutrients and water throughout the tree. Infected golden elders may wilt, foliage may brown and the tree may dieback and lose its leaves. The xylem of the tree (interior wood) will display a streaked discoloration. There is no cure or treatment for verticillium wilt. Newly planted and drought-stressed golden elders are susceptible to this disease. Severely infected trees will succumb to the disease, and should be removed and destroyed.
Powdery mildew is a disease transported by fungal spores. These fungal spores develop on dead and dying debris that lies around the planting area of the golden elder. Spores, transported by wind and rain, infect the foliage of the shrub. Golden elders with infected leaves develop tiny spots. As these small spots accumulate, the spots begin to appear as a powdery white covering of mildew that spreads across the surface of the foliage. Although mildew can be wiped from the leaves, the foliage spots become deadened areas that kill the leaves. The infection also causes foliage distortion, growth stunt and premature defoliation. The potential of powdery mildew is greatly reduced by keeping the golden elder’s planting area free of debris and defoliation. The disease can be treated with fungicidal sprays designed for powdery mildew infections.
Leaf spot is a fungal disease that lies dormant on fallen debris throughout the winter months. Spores are released during the windy and rainy months. Fungal spores land on the foliage surfaces of the golden elder and germinate, when water settles on the leaves developing into tiny spots, which enlarge and multiply as the infection progresses. Infected foliage should be pruned from the tree and all debris around the tree should be removed to prevent further infection, according to University of Connecticut Integrated Pest Management. Leaf spot can be treated and prevented with fungicidal treatments.