With the exception of slugs and more recently foliar nematodes, hostas have generally been considered pest-free. That may be changing. Recently a virus disease, hosta virus X (HVX) has been identified that causes mottled leaf coloring in hostas. Early on, some plants with the disease were propagated and grown for their "interesting" foliage. Currently, plants with "interesting" foliage need to be evaluated closely as the plant may be infected with the virus disease, which can spread to other plants. The principle route of infection is spread of sap from an infected plant to a healthy one by contaminated hands or tools. At present there is no evidence that the disease is transmitted by insects, but feeding by rabbits, deer or slugs could potentially vector infected plant sap from plant to plant.

Symptoms and Diagnosis

Early signs may be blue or green colored spots on the gold part of hosta leaves. These markings may bleed into the leaf giving it a mottled appearance. Leaves may appear lumpy. Other plants may develop brown spots and twisted leaves.

Integrated Pest Management Strategies

1. Remove diseased plants. There is no cure for the disease. As soon as a plant shows symptoms of the disease it should be removed and destroyed. Do not compost in your home compost pile. Rather, dispose to a commercial yard waste composting facility or to a landfill. Clean and sterilize any tools used to remove the plant.

2. Be vigilant. Keep an eye on new hosta plants you have planted and remove any that show signs of the disease. Ideally, new plants should be planted in an area away from other plants so they can be observed, but this is usually impractical and undesirable in the home garden. Be wary of digging up "unusual" looking plants in a neighbor's or friend's garden as the plant may be infected.

Some cultivars known to be infected with hosta virus X disease include: 'Leopard Frog', 'Lunacy', 'Eternal Father', 'Kiwi Watercolours', 'Breakdance', and 'Parkish Gold'.

These hosta cultivars have mottled foliage that is not believed to be the result of hosta virus X disease: 'Cynthia', 'Laella', Kiwi Forest', 'Wild Bill', 'Xanadu Paisley'.

Organic Strategies

Both of the recommended IPM strategies are strictly organic approaches.