Pachysandra blight
I’ve had a few phone calls this spring about sudden dying of mature patches of Pachysandra. This leaf and stem blight is a destructive disease of Pachysandra caused by a fungus (volutella). Brown blotches on the leaves are usually the first sign. These will increase in size until the entire leaf turns brown, or black. In severe infections plants will wither and die. Pink masses of spores may be visible. Plants die in patches.
Disease spread is fast in densely crowded patches or in areas weakened by drought or winter injury. Since plant stress is a factor, maintain the health of your groundcover.
Unfortunately the only means of control is to remove the infected areas. Remaining plants may be thinned out to improve air circulation and decrease the chance of re-infection. Fungicides may be used to control the fungus.
Pachysandra is also susceptible to Euonymous Scale so check for these and control with an appropriate insecticide if required. The presence of Scale will stress the plant and leave it open to infection.
Box Elder Beetles
These colorful bugs are most visible in the fall when they tend to congregate en masse on warm sunny walls. But we seem to be getting a few in every week so I thought they deserved a mention.
Box Elder Bugs are primarily a nuisance and not really harmful. They may be controlled with insecticides such as Safer’s Trounce if desired.
Powdery Mildew
This is also a fungal disease, but unlike the Pachysandra blight mentioned above it is easily controlled and seldom fatal to the plant.
Powdery mildew is just that, a white powdery coating on the foliage or buds and stems of plants. This fungus is spread by spores so if you have a particularly prone plant (like Lilacs or Summer Phlox) do not overhead water. This spreads the spores once they are present. Water only the soil when possible. Susceptible plants can be sprayed with a fungicide at the first sign of the disease and every 10-14 days thereafter as long as the disease persists.
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