Why Do The Leaves On My Apple Tree Look Unhealthy?

Do the leaves of your apples have olive-brown, velvety spots that become dark and corky?

Are the new leaves of your apples twisted or curled and covered with a sticky coating?

Do the leaves of your apples have pale yellow spots that enlarge and turn orange?

Do the leaves of your apples have a light powdery coating?

Did the leaves of your apples suddenly blackened?

Have the leaves become yellow before fall?

Brown, velvety or corky surface lesions on apple leaves usually indicate a disease - Apple scab. This fungal disease spread during springtime when warmth and moisture promote last year's spores to discharge and fly. To prevent apple scab, destroy all dropped leaves before spring. Growing season applications of copper or sulfur sprays can help a lot in control of the disease. Pruning trees to encourage air circulation also helps.

Distorted leaves and sticky, white coating on them usually indicates aphids. These tiny insects can vary in color, green, pink, black, gray to completely white. They cluster under leaves and on growing tips where they feed on plant sap. Leaves become distorted and later drop from the plant. You can control them by washing them off the plant with water spray. Introducing their natural predators will keep their number low. Insecticidal soap should be used only with severe infestations.

Pale yellow spots that later turn orange may indicate a fungal disease - Cedar-apple rust. Fungi that transfers Cedar-apple rust overwinters on various juniper species. In the spring airborne spores fly from junipers and infect apples. Removing nearby junipers won't help as the spores can be transferred from miles away. Sulfur sprays during springtime are effective against this fungus.

White, powdery patches on the leaves are caused by a fungal disease - Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the apples by thining their branches. Keep foliage dry when watering. Affected leaves and fruits should be cut off and removed.

When leaves suddenly blacken the cause may be bacterial disease - Fire blight. Other symptoms include bent over tips of growing shoots. Fire blight bacteria is very dangerous as it can travel to the roots and kill the entire tree. For control during the growing season, cut all infected parts at least 6 inches below the infected area and destroy all parts. Between cuts, dip tools into isopropyl alcohol to disinfect them. Resistant cultivars are "Arkansas Black", "Baldwin", "Empire" and "Winesap".

Yellow leaves may indicate a San Jose Scale. Other symptoms include red skin spots with white centers and the death of whole branches. Clusters of these sucking insects cling to the bark and appear as small gray bumps that can be easily scraped off with a fingernail. Control them with late winter application of dormant oil spray.

Some environmental issues might have caused your plant leaves to look unhealthy. Apples love full sun, well-drained and evenly moist soil, moderately fertile soil that is only slightly acidic. Try not to let their branches become too crowded, so prune them each winter.