Hostas & the Anthracnose Pest

Hostas are low maintenance, shade-tolerant plants with attractive blossoms and foliage. Hostas vary in color and size depending upon the cultivar. They are susceptible to several different fungal infections, including anthracnose.

Features

• The Colletotrichum fungus causes anthracnose in hostas. The disease is most active in warm and humid weather conditions. It spreads from one plant to another by wind and rain, as well as by insects or on infected seeds or rhizomes, according to the University of Massachusetts Extension.

Effects

• Anthracnose is characterized by large irregularly shaped spots with dark borders. The dark spots fall out of the leaves, resulting in a tattered appearance. The spots occasionally grow together and cause leaf death. Fungal fruiting bodies called acervuli appear on infected leaves.

Prevention/Solution

• Anthracnose, which is the most widespread disease in hosta plants, lessens the plant's beauty but rarely causes death, according to the Iowa State University Extension. Protect healthy foliage by applying an appropriate fungicide. Water the soil rather than the foliage and avoid wetting the leaves. Anthracnose infections overwinter in leaf litter, so remove all dead leaves and plant debris that may harbor the fungus.