Pests
Symptoms Look at the very bottom of the trunk where it meets the soil. Peachtree borers leave a sticky, gummy ooze mixed with what looks like wet sawdust (called frass, the droppings and chewed wood the larvae push out). You may see a small mound of this gum and frass at the base. A young tree with several borers can be killed in one season, so this is one to catch early.Gummy ooze mixed with sawdust-like frass at the base of the trunk, right around the soil line, often with a mounded look where the bark meets the ground. Bark in that zone may be cracked or sunken. A heavily infested young tree loses vigor as the larvae girdle the inner bark; several borers in one trunk can kill a newly planted tree in a single season. Cause The larvae (young, grub-like stage) of the peachtree borer, a moth whose adults look like wasps and fly during the day. The adults lay eggs on the lower trunk in summer, and the larvae burrow into the bark at and below the soil line. Trees with existing wounds are hit hardest, but a healthy tree can be attacked too.Larvae of the peachtree borer (Synanthedon exitiosa), a clearwing moth whose adults are day-flying and wasp-like. Eggs are laid on the lower trunk in summer; the larvae tunnel in the inner bark at and just below the soil line. Trees already stressed by winter injury, mechanical wounds, or canker are attacked first, but healthy bark can also be entered. Organic treatment Once the larvae are tunneling inside, no spray reaches them. The backyard fix is to scrape soil away from the base in late summer or fall, find the holes marked by gum and frass, and kill the larvae with a thin, stiff wire pushed into each hole. Then smooth the soil back. Avoid nicking the trunk base with mowers or trimmers, since wounds invite the moths.There is no rescue spray once larvae are tunneling inside the trunk. The practical home control is to expose the crown in late summer or fall, find the entry holes by the gum and frass, and kill larvae by hand with a thin wire (worming). Keep the trunk base free of wounds. Pheromone mating-disruption is used commercially but is not practical for a single backyard tree. Prevention Keep mowers and string trimmers away from the trunk; the wounds they leave attract the egg-laying moths. Keep grass and weeds cleared from the base so you can see the soil line, and check it every late summer for fresh gummy ooze so you catch borers early.Protect the lower trunk from mechanical injury (the wounds that draw egg-laying females), keep the tree vigorous, and clear weeds and tall grass from the base so the crown stays open and easy to inspect. Inspect the soil line each late summer for fresh gum so an infestation is caught in its first year.
Symptoms Sticky gum and sawdust-like frass on the upper trunk and main branches (the scaffolds), not down at the soil line. It almost always shows up on an existing wound, pruning cut, or canker. Over time the affected branches weaken.Gum and frass higher up than the peachtree borer, on the upper trunk and scaffold limbs rather than at the soil line, almost always centered on existing wounds, pruning cuts, or canker margins. Repeated attacks weaken scaffolds and can girdle limbs. Cause The larvae of the lesser peachtree borer, a close relative of the peachtree borer. This one attacks wounded bark up in the branches instead of at the base, so it tends to follow canker (a sunken, dead patch of bark) and pruning cuts.Larvae of the lesser peachtree borer (Synanthedon pictipes), a clearwing moth closely related to the peachtree borer. Unlike its relative, it targets wounded bark up in the canopy, so its damage is tightly linked to Cytospora canker and pruning injuries. Organic treatment No spray reaches the larvae once they are inside. Where you can reach them, dig them out with a wire as for the peachtree borer. The better fix is to stop giving them wounds to enter: prune cleanly, cut out dead cankered bark, and keep the tree vigorous.As with the peachtree borer, no spray reaches established larvae; worm them out by hand where accessible. The durable control is to minimize the wounds it colonizes: prune cleanly in late dormancy, remove cankered wood, and keep the tree healthy. Prevention Make clean pruning cuts in late winter, cut away any dead or cankered bark, and do not leave torn bark or branch stubs. Fewer wounds means fewer places for this borer to get in.Prune at the right time (late dormant season) with clean cuts, remove canker promptly, and avoid leaving stubs or torn bark. A tree kept free of open wounds gives this borer few places to establish.
Symptoms On small developing nectarines, look for a curved, crescent-shaped scar, the mark the beetle leaves when it lays an egg. Damaged fruit often drops early, and some that stays on the tree ends up misshapen or has a grub inside. You see this soon after the petals fall.Small young fruit carries a distinctive crescent-shaped scar where the female cut a slit to lay an egg. Infested fruit often drops early; fruit that hangs on may be gnarled or have a grub tunneling inside. Damage appears shortly after petal fall. Cause A small beetle with a long snout called the plum curculio. The adults show up around bloom and start damaging the little fruits right after the petals drop, laying eggs inside them. The larvae then feed within the fruit.The plum curculio (Conotrachelus nenuphar), a small snout beetle. Adults emerge around bloom and attack fruit from petal fall onward, laying eggs in the developing fruit; the larvae feed inside. Organic treatment Early in the morning the beetles are slow. Spread a sheet under the tree, tap the branches so the beetles fall, and destroy them. Pick up and throw away any dropped fruit promptly so the larvae inside do not mature. A kaolin clay spray (a fine white mineral coating) starting at petal fall helps keep them off.For a backyard tree, jarring the limbs over a sheet in the early morning when the beetles are sluggish, then destroying what drops, reduces the population. Promptly gather and dispose of dropped infested fruit to break the cycle. Kaolin clay applied from petal fall is an organic deterrent. Prevention The main thing is cleanup. Pick up fallen fruit all season so the larvae inside cannot finish growing in the soil under the tree. Keeping the ground clear lowers the number of beetles the next year.Sanitation is the backbone: remove dropped fruit through the season so larvae cannot complete development in the soil beneath the tree. A clean orchard floor and prompt fruit pickup steadily lower pressure year over year.
Symptoms Early on, the tips of new shoots wilt and die as larvae tunnel into them, which looks like small flags of dead growth. Later in the season the larvae bore into the fruit, often near the stem, with a little gum at the entry hole and tunneling inside.Early in the season, new shoot tips wilt and die back (flagging) as larvae bore into tender growth. Later generations tunnel into fruit, often entering near the stem, leaving a gummy entry point and internal feeding near the pit. Cause A small moth called the Oriental fruit moth. It has several rounds of larvae through the summer. The first rounds attack shoots and the later rounds attack fruit, so the damage moves from twigs to nectarines as the season goes on.The Oriental fruit moth (Grapholita molesta). It produces several overlapping generations a season; early broods attack shoots, later broods attack fruit, which is why damage shifts from twigs to fruit as summer progresses. Organic treatment Clip off and destroy the wilted shoot tips early, before the later larvae move to the fruit. Remove any tunneled fruit you find. For one backyard tree, this cleanup is the main organic control.Prune out and destroy wilted shoot tips early to remove larvae before they reach the fruit-feeding generations. Remove infested fruit. Pheromone mating disruption is the commercial tool; for a single tree, shoot sanitation plus prompt fruit removal is the practical organic approach. Prevention Watch for wilted shoot tips early and clip them off as they appear, and clean up fallen fruit. Knocking back the early larvae means fewer of them reach your nectarines.Keep on top of early shoot flagging so each generation is knocked back before it builds, and clear dropped fruit. Lower early pressure means less fruit damage later.
Symptoms Ripe nectarines have sunken, puckered, dimpled patches, a look growers call catfacing. It comes from insects feeding on the fruit when it was small. Because a nectarine has bare, smooth skin, these marks show up much more than they would on a fuzzy peach. The fruit is still usable; the damage is mostly on the surface and does not spread.Mature fruit shows sunken, dimpled, corky distortions, the puckered 'catfaced' look, where feeding occurred on young fruit. On a nectarine's smooth, fuzzless skin these scars and dimples stand out far more than on a peach, so the same feeding is more disfiguring cosmetically. The damage is mostly surface, can run into the flesh, and does not spread or rot on its own. Cause A group of insects, mainly stink bugs and a small one called the tarnished plant bug, that pierce the young fruit to feed. The spots they feed on stop growing while the rest of the fruit keeps swelling, so the nectarine ends up dimpled.A group of true bugs, chiefly stink bugs and tarnished plant bug, that pierce young fruit to feed. The cells around each feeding site stop expanding, so the fruit grows in around them and ends up distorted at maturity. On a fuzzless nectarine the resulting scarring is more visible than on a peach, so nectarines show catfacing damage more readily. Organic treatment These bugs come in from nearby weeds and brush, so spraying one tree does little. The better approach is to keep the area around the tree mowed and clear of weedy growth where the bugs gather.These bugs move in from surrounding weeds and brush, so control is mostly habitat management rather than spraying a single tree. Keep the area around the tree mowed and free of broadleaf weeds where the bugs build up. Prevention Keep a mowed, weed-free zone around the tree. Removing the weedy plants the bugs live in means fewer of them move onto your fruit.Manage the surrounding vegetation: a mowed, weed-free zone around the tree removes the broadleaf hosts these bugs breed in and reduces how many move onto the fruit.
Symptoms Pale, silvery or tan rough patches on the skin, often a ring around the stem or streaks down the fruit, appearing as the nectarine grows. Because a nectarine has smooth, bare skin, these thrips scars show up much more than they would on a fuzzy peach, and bad early feeding can leave the fruit misshapen.Silvery or tan russeted scarring on the fruit surface, often as a pale halo around the stem end or streaks down the side, showing up as the fruit sizes. On a nectarine the scarring is far more conspicuous than on a fuzzy peach, since the smooth skin has no down to hide the marks; heavy early feeding can also deform the fruit where the scarred tissue fails to expand. Cause A tiny insect called western flower thrips feeds on the blossoms and the tiny new fruit right around bloom. The feeding scars the skin, and the scar gets bigger as the fruit grows. Nectarines show this damage more than peaches because their skin is smooth and bare, with no fuzz to protect it or cover the marks.Western flower thrips (Frankliniella occidentalis), a tiny slender insect that feeds on the flowers and the young fruit surface at and just after bloom. Their feeding scars the skin, and the scars enlarge as the fruit grows. Nectarines are hit harder cosmetically than peaches because the fuzzless skin offers no protective barrier and shows every mark. Organic treatment Thrips are tough to stop once they start, so for a backyard tree the best plan is to accept some scarring and reduce their numbers: mow down flowering weeds near the tree while it is blooming, because thrips build up on those flowers and move to the tree. The marked fruit is still fine to eat; just peel it if the skin is rough.Thrips are hard to control once feeding starts, and for a backyard tree the practical approach is tolerance plus habitat management: keep flowering weeds mowed down near the tree during bloom, since they harbor thrips that move onto the opening flowers. Most scarring is cosmetic and the fruit is still good to eat; peel it if the skin is rough. Prevention Mow or pull flowering weeds near the tree before and during bloom, since those flowers are where the thrips come from. Keep the tree healthy so a little scarring does not matter much. The damage is only skin-deep, and the smooth skin is simply part of growing nectarines instead of fuzzy peaches.Clear flowering weeds from around the tree before and during bloom to cut the source population, and keep the tree vigorous so light scarring does little real harm. The damage is skin-deep and specific to the smooth-skinned fruit, an inherent trade-off of growing nectarines rather than fuzzy peaches.
Diseases
Symptoms In spring, new leaves come out thick, puckered, and curled, with a red or purple tint that fades to yellow before the leaves drop. The tree usually grows a fresh set of leaves afterward, but losing the first set early weakens it and cuts the nectarine crop.In spring, newly emerging leaves are thickened, puckered, and curled, flushed red to purple before fading to yellow, then dropping. Severely infected shoots may be stunted. The tree pushes a second flush of leaves after the infected ones fall, but the early defoliation saps vigor and reduces the crop. Cause A fungus called Taphrina deformans. Its spores spend the winter on the bark and buds, then infect the brand-new leaves as the buds swell in cool, wet spring weather. It only infects once each spring, so the timing of control matters.The fungus Taphrina deformans. Spores overwinter on the bark and around the buds and infect the tiny leaves as the buds swell in cool, wet spring weather. It infects only once each spring; once leaves are out and the weather warms, new growth is no longer susceptible. Organic treatment Once you see the curled leaves, it is too late to fix them for that year. The one thing that works is a single, well-timed spray of fixed copper (an organic-approved copper fungicide) while the tree is leafless and dormant, either in fall after about 90 percent of the leaves have fallen, or in late winter just before the buds swell. Spraying after the leaves are out does nothing. Keep the tree watered and fed so it bounces back from a bad year.There is no cure once the curled leaves appear; the damage is already done for that season. The single effective measure is a dormant fungicide, and the timing is what matters: one thorough application of fixed copper either in autumn after about 90 percent of the leaves have dropped, or in late winter just before the buds swell. Support the tree through a bad year with steady watering and balanced feeding so it recovers from the second leaf flush. Prevention In areas where leaf curl shows up, put on the dormant copper spray on schedule every year. It is easy to prevent with the right timing but impossible to stop once the leaves curl. Cool, wet springs make it worse, so do not skip the spray in those years.Apply the dormant copper spray on schedule every year in regions where leaf curl is common; the disease is easy to control with correct timing but unstoppable once missed. Cool, wet springs raise the risk, so do not skip the spray in mild, damp years.
Symptoms At bloom, infected flowers go limp and brown, and small gummy dead patches form on the nearby twigs. As the nectarines ripen, brown spots appear and spread quickly, sometimes rotting a whole fruit in a day or two in warm, wet weather, with a dusty tan fuzz on the surface. Because a nectarine has no skin fuzz to slow the fungus down, it rots faster and harder than a peach, and brown rot is the worst disease nectarines get. Rotted fruit shrivels into a hard, dried 'mummy' that hangs on the tree.At bloom, infected blossoms wilt and turn brown, and the infection runs back into the twig to form a small gummy canker. As fruit ripens, brown circular spots appear and spread fast, sometimes rotting the whole nectarine within a day or two in warm, wet weather, with a dusty tan spore mass on the surface. The smooth, fuzzless skin gives the fungus an easier entry than a peach's downy skin, so nectarines rot faster and harder; brown rot is the most damaging disease of nectarines and can take a large share of the crop. Rotted fruit dries into a 'mummy' that clings to the tree. Cause A fungus called Monilinia fructicola. It survives the winter in dried mummy fruit and in dead twig patches, then releases spores at bloom that infect the flowers. Those flower infections later cause the fruit to rot. Warm, humid, wet weather makes it spread fast, and a nectarine catches it more easily than a peach because its skin has no protective fuzz.The fungus Monilinia fructicola. It overwinters in mummified fruit, whether still hanging in the canopy or fallen below, and in twig cankers; spores released at bloom infect flowers, and those infections later seed the fruit rot. Warm, humid, wet conditions drive rapid spread, and a nectarine's bare skin, which lacks the protective fuzz of a peach, makes it more susceptible than a peach to the fruit-rot phase. Organic treatment The main control is cleanup: take off and destroy every dried mummy from the tree and the ground, and prune out the gummy dead twig patches, since these hold the spores. If the weather is wet during bloom, an organic-approved spray at bloom helps protect the flowers. As soon as you see a nectarine rotting, pick it and throw it away so it does not spread.Sanitation is the core control: remove and destroy every mummy from the tree and the ground, and prune out gummy twig cankers, because these are the spore sources. During a wet bloom, an organic-approved bloom-time fungicide reduces blossom blight. Once fruit is rotting, pick and dispose of it promptly so it does not seed more infections. Prevention Cleanup all year prevents most of the damage, and it counts even more for nectarines than peaches: never leave dried mummies on the tree over winter, pick up dropped fruit, and prune so the tree is open and the nectarines dry fast after rain. Thin the fruit well so they do not touch, because the rot spreads where fruit rubs together. Pick fruit on time, handle it gently so it does not bruise, and chill it soon after picking.Year-round sanitation prevents most loss, and it matters even more on nectarines than on peaches: never leave mummies on the tree over winter, remove dropped and thinned fruit, and keep the canopy open with good pruning so fruit dries quickly after rain. Thin generously so fruit does not touch, since skin-to-skin contact spreads the rot. Harvest promptly and handle fruit gently, since wounds let the rot in, and cool fruit soon after picking.
Symptoms Leaves get small angular water-soaked spots that turn brown and fall out, leaving little holes, called a shot-hole look. Bad cases turn leaves yellow and thin out the tree. On the fruit, small sunken spots and skin cracks form, and they show up more on a nectarine's smooth skin than on a fuzzy peach. Nectarines are generally more prone to this than peaches, so how badly a tree is hit depends a lot on the variety you choose.Small angular, water-soaked spots on leaves turn brown and drop out, leaving a shot-hole look; heavy infection yellows and thins the canopy. On fruit, small sunken spots and cracks develop on the skin, and on a nectarine's smooth skin the pitting and cracking are more conspicuous and disfiguring than on a fuzzy peach. Nectarines are generally more susceptible than peaches, so susceptibility varies sharply by cultivar and variety choice is the main lever. Cause A bacterium (a microscopic organism, not a fungus) called Xanthomonas. It spreads in warm, wet weather and builds up when there are other susceptible peach or nectarine trees close by. Nectarines catch it more readily than peaches, and the spots can look like spray damage.The bacterium Xanthomonas arboricola pv. pruni. It spreads in warm, wet weather and builds up where susceptible peach and related trees grow nearby. Nectarines are generally more susceptible than peaches, and symptoms are sometimes mistaken for spray injury. Organic treatment There is no good home cure once it shows up. Copper sprays help a little as prevention but can hurt the tree if overused, so they are not a dependable fix. The best you can do is keep the tree healthy so it shrugs off the damage.Home options are limited once symptoms appear: copper sprays help more as prevention than cure and can injure the tree if overused, so they are not a reliable home fix. Keeping the tree vigorous helps it tolerate the disease. Prevention The best prevention is the variety you pick, and it counts even more with nectarines because they get bacterial spot more easily than peaches. Choosing a nectarine known to resist or tolerate it, such as Fantasia or the disease-tolerant Hardired, avoids most of the trouble, so it is a decision to make before planting. Good airflow and a healthy tree also help.The most effective measure is choosing a resistant or tolerant cultivar at planting, which matters even more on nectarines than peaches since nectarines are more susceptible; among the varieties here, Fantasia is one of the more bacterial-spot-tolerant, while Hardired is bred for disease tolerance. This is largely a variety decision made before the tree goes in. Good airflow and tree vigor reduce severity.
