Why Are The Fruits On My Apple Tree Developing Poorly?

Are the fruits on your apple tree surrounded by brown, crumbly excrement?

Are the fruits on your apple tree dimpled with brown tunnels in the flesh?

Do the young apple fruits have crescent-shaped scars on them?

Do the apple fruits have brown, velvety or corky surface lesions on them?

Do the apple fruits have rotting spots on them?

Are the spots dark with alternating black and brown circles?

Are the spots tanned and slightly sunken?

Do the apple fruits have yellow spots on the skin that later turn orange?

Do the apple fruits have netting or russeting surfaces?

Do the apple fruits have red skin spots bearing white centers?

Brown, crumbly excrement that surrounds apple fruits are caused by Codling moth larvae. These white or pinkish caterpillars feed by tunneling through the fruit. Control is very difficult without using chemical insecticides. You can kill their eggs by spraying superior oil on leaves and twigs 2-6 weeks before blossoming. One of the newer and more effective methods of control is biological insecticide CYD-X, codling moths granulosis virus.

These symptoms most likely indicates Apple maggots. These, 1/4 of an inch small maggots feed by tunneling trough apple fruit. In late June they morph into adult flies. Since they are attracted to the fruit by sight, you can trap them by hanging red balls with a sticky coating on the trees. 4-8 traps by a tree will be enough to control their numbers. You should clean traps every few days and reapply the sticky coating.

Crescent-shaped scars on fruits are caused by beetles - Plum curculios. These pests are common mostly to the Rockies region. You can control their numbers by gently shaking the tree and the branches or hitting the branches with the padded mallet and when the bugs fall, collect and destroy them. If you do this twice a day, you won't have trouble with them.

Brown, velvety or corky surface lesions on apple fruits 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.

Dark spots with alternating black and brown circles indicate a black rot Summer disease. Summer disease fungi overwinter in mummified fruit and cankers on diseased wood. To control, remove and dispose of all cankered wood. Collect and destroy mummified fruit. Black rot attacks weakened or wounded trees, so keep them healthy with good pruning and nutrition.

Tanned and slightly sunken spots indicate a bitter rot summer disease. Summer disease fungi overwinter in mummified fruit and cankers on diseased wood. To control, remove and dispose of all cankered wood. Collect and destroy mummified fruit.

Spots made of watery decay indicate a white rot summer disease. Summer disease fungi overwinter in mummified fruit and cankers on diseased wood. To control, remove and dispose of all cankered wood. Collect and destroy mummified fruit. White rot attacks weakened or wounded trees, so keep them healthy with good pruning and nutrition.

Pale yellow skin 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.

Netting or russeting surfaces on apples may indicate 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.

These symptoms usually indicate a San Jose scale. 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 with late winter application of dormant oil spray.

Apple fruits with raised black spots or brown smudges on the surface may indicate flyspeck or sooty blotch. Black spots are flyspeck and brown smudges are sooty blotch. Both of these blemishes are fungal diseases and both can be controlled with sulfur sprays.