What Keeps Peaches from Ripening on the Tree?

Insects

Detrimental insects such as the oriental fruit moth and the plum curculio prevent peaches from ripening on trees. Larvae of the oriental fruit moth burrow into peaches and terminal shoots of trees, causing tiny holes in the fruit, spotted peach skin, premature fruit drop and unripe fruit. However, the holes made by the borers are so tiny that the damage is not visible until you cut the fruit open. The plum curculio is a small beetle that feeds on the flesh and burrows within the flesh to lay eggs. Symptoms of damage include tiny holes in the fruit, premature fruit drop and unripe fruit.

Control oriental fruit moths with pheromone traps. Hang the traps in early spring and remove collected moths every two weeks. Space multiple traps 100 feet apart to prevent interference. Use registered sprays to manage both the pests. Apply the selected spray as soon as peaches appear on the tree, before the petals fall, to prevent spread. Adopt good cultural practices to keep the pests from damaging your peaches.

Fungal diseases such as scab and brown rot adversely affect fruit production in peach trees. Caused by the fungus Cladosporium carpophilum, scab causes tiny olive-green spots on the skin that merge to form blotches, stunted growth and premature fruit drop. Symptoms of brown rot include brown blossoms, flower wilt, fruit drop and unripe fruit. Caused by the fungus Monilinia fructicola, brown rot is prevalent during wet conditions and open wounds. Adopt good sanitation practices to control both fungal diseases on peach trees. Monitor the fruit for insect infestations and treat immediately. Adopt a fungicide to manage the disease.

Peach trees require full sunlight, regular pruning, irrigation and fertilization to produce healthy fruit. Grow peach trees in well-draining, fertile soils with soil pH between 6.0 and 7.0. Feed mature trees a well-balanced 10-10-10 fertilizer in spring, and newly planted trees every 40 days. Provide the trees 2 to 3 inches of water every week, unless supplemented by rainfall. Prune the trees to remove dead, damaged or diseased wood that helps increase sunlight penetration and helps the fruit ripen.