Leaf and stem blight, a destructive disease of pachysandra, is caused by the fungus Volutella pachysandrae. Both the leaves and stems of pachysandra are attacked by this fungus. Brown blotches on the leaves are usually the first noticeable symptoms. The blotches gradually increase in size until the entire leaf turns brown or black and dies. In severe infections, stem cankers (browning of the stem at the terminal, mid-stem or ground level) occur and will cause the plant to wither, turn brown or black and die. During wet weather, affected parts are often covered by pink masses of fungus spores. Further spread of the disease throughout the planting is by means of these spores. Plants die in patches, and the disease commonly produces a circular pattern in the bed.
Pachysandra grows best in beds that are lightly shaded, do not retain excessive soil moisture, are protected from deicers and winter winds that cause desiccation.
Disease spread is most rapid in dense overcrowded plantings and in plantings weakened by drought, winter injury, shearing, injury at planting, or attacks by insects. In addition, disease development is encouraged by using damp, heavy mulch, such as leaves or compost, which provides excessive moisture.
Rogue and destroy all severely diseased plants. Thin thick plantings to increase light and air circulation. Water plants in the morning so the foliage dries quickly, reducing chances of an infection. Maintain healthy thriving plants – these are less susceptible to blight.
If you are growing Japanese pachysandra (Pachysandra terminalis) and Volutella blight continues to be an ongoing problem, you may want to re-plant with Allegheny pachysandra (Pachysandra procumbers), a less susceptible and native pachysandra.
Fungicides are an option if volutella blight has been a problem in the past. Since the disease spreads rapidly in stands that have been weakened by insects, make an attempt to control them. Scale insects, particularly euonymus scale, can be very destructive. For control of scale, prune badly infested plants. Spray with an insecticide during the first week of June and repeat in early July.
For additional management options, contact your local Cooperative Extension center for or visit the on-line guides of Cornell University and Penn State. This information may not apply to your state.
Prepared by: David B. Schroeder, Extension Plant Pathologist andEdmond L Marrotte, Consumer Horticulturist
Updated by: Mary Concklin, IPM, University of Connecticut. 2011.
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