Plant Diseases That Affect Hostas

Hosta Virus X

• Hostas can become infected with a virus called hosta virus X, also called HVX. Any type of hosta can be infected with this virus, but the most common types to get this disease are the Striptease, Sum and Substance and Gold Standard varieties. There are tests to be sure the virus is present, but the cost and unreliability of the test makes it a non-viable option. The best way to tell if your plant has been infected is to look at the leaves; they will be discolored or have irregular patterns on the leaves.The symptoms may not show for years after infection, so carefully inspect all hostas available before purchase, If even one plant shows the disease, do not purchase any of the plants, because the disease spreads rapidly. If you have an infected plant, the only cure is to remove the plant, taking as many roots as possible, and not replanting in that area until all the roots have died. Burning or discarding the infected plant can prevent other plants from being infected, but is not a guarantee.
  
  

Southern Blight

• Southern blight is caused by the fungus Sclerotium rolfsii. It attacks first at or below the soil surface, attacking the roots and outside leaves of the plant. Symptoms of this disease are yellowing leaves and stems that fall over, then die. The cure is to dig the entire plant and separating and burning or discarding the affected parts. Before replanting the rest, you should dip it in a commercial fungicide or a solution of 1 tbsp. of alcohol to 1 gallon of water to ensure the remaining plant is not infected.
  
  

Crown Rot

• Crown rot is a fungal infection caused by overly moist soils, and occurs in warmer climates mostly, but can occur is milder climates as well. The only symptom of this type of fungal infection is yellowing leaves that fall away from the plant. Commercial fungicides and homemade fungicides may keep the disease from spreading to healthy plants, but the only cure, once infected, is to remove the infected plant or dividing the entire plant, keeping the healthy growth. Overly packed soil around the plants may cause this fungus, so keeping the growing soil aerated will help prevent fungi from invading your plants.
  
  

Pests

• Hostas are relatively pest free, but snails and slugs feed on their leaves. Vine weevil larvae eat the roots of the plants, killing them slowly, while the adult beetles eat the leaves. These are easily seen and killed by squashing, but organic and commercial slug controls repel and remove the infestations as well. Regular digging in the soil around hostas keeps the larvae and eggs to a minimum. Spray new plant growth with a solution of 10 percent household ammonia and 90 percent water to repel and kill slugs. Remove drooping leaves from the plant to eliminate climbing ramps, forcing slugs to move to easier prey. Hand pick the snails, dropping them into a solution of 90 percent water and 10 percent ammonia. Locate birdhouses near your plants to encourage birds to feed on the snails and slugs. Diatomaceous earth spread around your plants repels infestations by cutting the snail's stomach areas as they slide through, causing them to dehydrate and die. .
  
  

Other Problems and Animals

• Garden sprays and other pollutants can cause brown spots on your hostas. These are harmless and removing the browning leaves solves the problem. Frost can cause the edges of the leaves to brown, or small brown spots on leaves. Wet leaves, scorched by the sun are another harmless, but ugly problem, that can be cured by removing the affected leaves. Keep your plants growing in shaded areas to prevent the problem. While hostas are not normally attacked by rodents and animals, deer love to feed on the entire plant. An 8-foot fence is necessary to keep deer at bay. Other remedies, such as leaving human scent in the area, hanging shiny CDs or soaps from string near the plants, scarecrows and large dogs, can be effective, but not a guaranteed success, as deer tend to return to plants they like to eat, regardless of obstacles.