Hippeastrum Fungus Treatment

Fungal Infection

• Of the several diseases hippeastrum bulbs are susceptible to, the fungal disease commonly knows as "red blotch" is one of the most common. The fungus, called Stagonospora curtisii, attacks the fleshy bulbs and leaves. Hippeastrum bulbs infected with red blotch rarely die from the disease, but an infection can weaken plants. Plants infected with Stagonospora curtisii develop red spots on the foliage and especially on the stems, deforming growth. Look for red marks on new foliage and stalks for early identification of the disease.

Prevention

• Plant bulbs in containers filled with sterile potting soil that provides good drainage and use pots that have holes in the bottom. Perpetually damp environments invite and perpetuate fungal infections. Look closely at new bulbs before you plant them. Hippeastrum bulbs often have red marks on the surface of the bulb that are harmless. Bulbs infected with Stagonospora curtisii have marks that penetrate the surface layer and part of the fleshy bulb.

Early Care

• Reduce watering for plants that show early signs of Stagonospora curtisii, allowing the soil to dry out slightly. When watering, wet only the soil and keep the leaves, stalks and flowers dry. Place the containers in a sunny spot and provide good air circulation or, in summer, place the pots outdoors. Bulbs planted in soil in the garden are less susceptible to the disease. When infections appear, reduce watering and keep the foliage dry. Dig up and discard heavily infected Hippeastrum plants.

Treating Bulbs

• According to the University of Florida IFAS Extension, red blotch fungus on Hippeastrum bulbs is hard to control. Destroy any plants, bulbs or seedlings infected with the disease. The university suggests soaking the bulbs in a hot water bath for 30 minutes. Remove any soil from around the roots and place the bulbs in a container of water that is between 104 to 114 degrees F. Using a fungicide such as thiophanate methyl will treat the fungus, but the product is expensive and generally hard to locate at your local gardening supply stores. As when using any fungicide, always follow the label's instructions concerning application and any warnings.