Pachysandra is a shade-tolerant ground cover that does not appear to be overused and that usually has few disease problems. About the only disease we see as a problem in pachysandra is Volutella blight. This disease occurs during wet springs, especially in cases where winter injury may have occurred. Volutella blight has shown up in central Illinois, and reports from Ohio indicate some injury there as well. (However, specialists warn not to mistake the blight for environmental scorching.)
Volutella is a fungus that can cause necrotic blotches on leaves and stems; the blotches range in color from brown to black. In very wet conditions, the fungus may kill large patches of plants. A diagnostic feature to look for is pink-to-orange spore masses on the underside of leaves or on stems. Look particularly for Volutella blight in dense plantings where heavy mulch has been used and where conditions are warm and moist. Pachysandra beds that have been stressed by winter, drought, insects, or overcrowding are more susceptible to this fungal disease.
Because growers tend to promote dense beds of ground cover, the disease will appear even in well-kept beds if the fungus is present and if warm, wet weather continues. Consult Report on Plant Diseases No. 649 for cultural disease control suggestions, and consider a protective fungicide spray for the planting now. (Actually, sprays could have been initiated when new growth started.) The applications are meant to be protective in mode of action; therefore, as long as weather conditions remain warm and wet, repeat the sprays at 10- to 14-day intervals. Some chemical options include chlorothalonil, copper, Duosan, Fore, mancozeb, and Zyban. Always follow label directions when using any chemical product.