1) Tarnished plant bug
- Adults are up to 1/4-inch in length and have a flattened oval appearance and a mottled brown color. Plant bugs can be a major peach and plum pest and are a difficult pest to detect and control.
- They are most active from the bloom stage to 5 to 10 weeks after bloom. They pierce and feed on blossoms and fruit causing deformities, shallow depressions, and fruit drop.
- Strings of oozing gum are often visible around feeding sites on fruit.
- To protect your crop from this pest, control weeds around trees, especially wild mustard, a preferred host plant. Apply a registered insecticide during the pre-bloom and petal fall periods when the pest is identified as a problem.
2) Oriental fruit moth
- Is considered a damaging pest. The larvae kill shoot tips and invade the flesh of the peach.
- Three or more generations develop in Maryland. This pest prefers peach trees to plum and cherry.
- Larvae of the early generations burrow down from the shoot tips and stunt extension growth. The larvae of later generations enter the fruit so that, by harvest, the fruit either falls to the ground or is wormy and useless.
- Larvae sometimes enter through the green fruit stem and no visible sign of internal injury is present.
- More often, you will notice scattered deposits of gum (thick sap) and frass (larval excrement) on the fruit surface.
- Prune out and dispose of wilted tips, 6 inches below visible damage.
3) Peach tree borers and lesser peach tree borers
- These are two similar pests that attack different parts of peach trees.
- Peach tree borer larvae grow into thick-bodied 1-inch-long larvae with brown heads that burrow through the inner bark of peach and nectarine trees at or just below the base of the tree. One borer can kill a small tree; two or more may kill larger trees.
- The lesser peach tree borer adult lays its eggs on the trunks and limbs of peach and nectarine trees, often in or around wounds and cankers caused by the Leucostoma fungus.
- The activities of both borers result in the oozing of amber gum by the peach tree, which often contains sawdust-like insect frass (larval excrement).
- The gum is produced by the tree as a defensive response to the injury.
- Where lesser peach tree borer wounds are found on small branches, they should be cut out and destroyed.
Adult borers (moths) begin emerging in late May to early June and can be found through September. The female adult is a large, blue and orange, a clear-wing moth that mates and lays eggs (mostly at the base of trees) soon after emergence. Larvae feed in tunnels below the bark and overwinter in trees, renewing activity in early spring.
Non-chemical management of peach tree borers
- Borers attack stressed trees. Keep peach trees in good health through proper planting, watering, fertilization, pruning, and pest management.
- Monitor for borer holes. In May, scrape away gum and dead bark from the lower trunk and large roots. Come back in 1 week and look for new gum and frass deposits. Make vertical cuts with a sharp knife through these entrance holes. Then, insert a stiff thin wire and stab larvae; repeat in 1 week and then mound soil over the damaged area (if low on the trunk).
- Wrap a band of corrugated cardboard on the lower trunk below soil level to prevent egg-laying or to trap larvae before they tunnel into the tree.
- Where holes and frass are observed but no sap is oozing from the tree, beneficial entomopathogenic nematodes may be used as a drench applied to the trunk or injected into borer holes.
- Bt can also be injected into borer holes with a syringe.
4) Plum curculio
Non-chemical management of plum curculio
- Hang plastic traps (empty 2-liter soda bottles) filled halfway with molasses, vinegar, and water, from tree limbs at petal fall.
- Cover individual fruits after pollination with small paper bags.
- Remove infested fruit from the tree.
- Lightly cultivate soil prior to budswell to disrupt/kill overwintering adults.
- Keep trees pruned and open (curculios prefer deep shade).
- Lay a white sheet under trees, tap limbs with a padded stick, and capture adults when they drop to the ground.
5) Cherry fruit fly
A common pest of sweet cherry and tart cherry fruits.
- Adult flies emerge from pupal cases in May. Adults feed in trees, mate, and then females lay eggs on ripening fruits.
- The larvae are 1/4-inch long, legless, and white to yellow in color. They feed singly on fruit pulp for up to 2 weeks.
- They complete their lifecycle when infested fruits fall to the ground.
- Hang sticky yellow traps in trees and monitor for the appearance of adults.
- They are two-thirds the size of houseflies and have dark bands on their wings.
- An insecticide should be sprayed five days after adults appear on traps.
- Laying a tarp or weed barrier fabric directly on the ground under the canopy in early May will prevent the adults from emerging.
- Promptly remove all infested fruit from the ground and the tree.
6) Japanese beetles
- They skeletonize the leaves (feed between the leaf veins) of stone fruit trees, especially sweet and sour cherry and Japanese plum.
- Knock Japanese beetles into a bucket of soapy water.
- Where feeding is severe, carefully use a labeled organic or chemical insecticide.
- Avoid Japanese beetle traps, because they tend to attract large numbers of beetles which can lead to additional plant damage.
7) Brown Marmorated Stink Bugs
8) Spotted wing drosophila (SWD), Drosophila suzukii
9) Fruit flies, yellowjackets, other wasps, and hornets
These insects will hover around ripe fruit. Do not allow any fruit to become overly mature on the tree and pick up fruit that drops to the ground. Do not use insecticides.