What Is Wrong With My Nectarine Tree Fruits?

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

Do the fruits have small brown spots that enlarge and grow fuzzy in humid weather?

Do the fruit have olive-green spots, mostly near stems?

Do the fruits have small, dark, and sunken spots or cracks in the skin?

Do the fruits have sunken, corky lesions?

Crescent-shaped scars on fruits are caused by beetles - Plum curculios. These pests are common mostly in the Rockies region. You can control their numbers by gently shaking the tree and the branches or hitting the branches with a 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.

These symptoms are caused by fungal disease - Brown rot (Monilinia fructicola). Other symptoms of brown rot may be withered blossoms, mummified fruits, and brown leaves. Remove and destroy both mummified fruits and twigs or branches with gummy lesions. For more control, spray sulfur early to protect blooms, then again later to protect the fruit.

Olive green spots on fruits are caused by fungal disease - Peach scab. Spots first appear on immature fruit and then turn brown and velvety. Infection arises from twig lesions, but damp weather spreads the fungus throughout leaves, fruit, and twigs. Infection is worst in warm climates and late-fruiting cultivars. To control the scab, remove infected fruit and clean up fallen leaves and fruit. For persistent infection, spray lime-sulfur or sulfur only every 10-21 days throughout the growing season. If spring weather is unusually warm and wet, spray sulfur weekly from the time flower buds first show green until blossoms begin to open.

Small, dark and sunken spots or cracks in the fruit skin are caused by bacterial leaf spots. This disease, common east of the Rockies, spreads in the spring from oozing cankers. Twig cankers appear water-soaked. Leaves turn yellow and drop. Infection weakens trees, makes them prone to winter injury, and reduces fruit quality and yields. Control it with copper spray.

Sunken, corky lesions on fruits are caused by tarnished plant bugs. Bugs hibernate in nearby weeds and move into trees in the spring. Trap them with white sticky traps or treat plants with a commercial pyrethrin spray or dust in the evening to control severe infestations. The best way to prevent this pest is through a thorough fall and spring cleanup. This will prevent it from overwintering.

Pinkish worms on your fruits are the second larval stadium of Oriental fruit moth. These insects can make lots of damage to the fruit trees and can be challenging to control. Timely BTK insecticide sprays and the introduction of parasitic wasp Macrocentrus ancylivorus will help in controlling them.