Pests
Symptoms On small developing apricots, 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 near the pit. Damage appears shortly after petal fall and is heaviest east of the Rockies. 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. It is mostly an eastern problem and rare in dry western climates.The plum curculio (Conotrachelus nenuphar), a small snout beetle native to eastern North America. Adults emerge around bloom and attack fruit from petal fall onward, laying eggs in the developing fruit; the larvae feed inside. There is little pressure in the arid West. 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 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). You may see a small mound of 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. Larvae tunnel the inner bark at the crown; several borers can girdle and kill a young apricot in a single season, and the wounds also open the door to canker. 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 the inner bark at and just below the soil line. It attacks all stone fruit, apricot included, and hits stressed or wounded trees first. Organic treatment Once the larvae are 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.There is no rescue spray once larvae are tunneling inside. 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 and paint it white against sunscald cracks. Prevention Keep mowers and string trimmers away from the trunk; the wounds they leave attract the egg-laying moths, and white trunk paint prevents the sunburn cracks they enter. 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.Protect the lower trunk from mechanical injury and sunscald (a white trunk paint helps), keep the tree vigorous, and clear weeds and tall grass from the base so the crown stays open and easy to inspect. Check the soil line each late summer for fresh gum so an infestation is caught in its first year.
Symptoms Clusters of small green or gray soft-bodied insects on the tips of new spring growth, curling and twisting the young leaves, with a sticky coating below that turns black and moldy. It is worst on young trees and mainly stunts new growth rather than ruining fruit.Dense colonies of green or mealy-gray aphids on the tips of new spring shoots, curling and distorting young leaves, with sticky honeydew below that blackens into sooty mold. Heaviest on vigorous young trees; it slows shoot growth but rarely harms fruit directly. Cause Small sap-sucking insects (green peach aphid and mealy plum aphid). Their eggs overwinter on the tree and the young hatch to feed on the soft new spring growth. The numbers usually drop on their own by midsummer as the shoots toughen and ladybugs and other helpers move in.Chiefly the green peach aphid and the mealy plum aphid. They overwinter as eggs on the tree and explode on the tender spring flush, feeding on sap; populations usually crash by midsummer as shoots harden and natural enemies build up. Organic treatment Often you can leave it alone, since ladybugs and other helpers clear it by midsummer. On a young tree that is badly hit, blast the colonies off with a hose, or spray the curled tips with insecticidal soap or horticultural oil. Do not over-fertilize, since lush new growth is what the aphids love.Often no action is needed, since beneficials clean it up by midsummer. For a heavy infestation on a young tree, a strong jet of water knocks colonies off, or insecticidal soap or horticultural oil applied to the curled tips works; protect the ladybugs and lacewings that do most of the control. Avoid high-nitrogen feeding, which fuels the soft growth aphids prefer. Prevention Avoid heavy feeding that pushes the soft growth aphids love, welcome ladybugs and lacewings, and do not panic over the spring leaf-curl, which usually does not hurt the crop. A dormant oil spray in late winter cuts down the overwintering eggs.Keep trees vigorous but not over-fed (high nitrogen invites aphids), encourage beneficial insects, and tolerate the early-season curl, which rarely affects the crop. A dormant oil spray reduces overwintering eggs where the pest is chronic.
Symptoms Tiny gray bumps crusting the bark of twigs and branches, and small red-ringed spots on the fruit. A bad case can weaken branches and even kill them, and it spots the fruit. The scales are easy to miss because each one is barely the size of a pinhead.Tiny gray, cone-shaped scales encrusting bark on twigs and scaffolds, sometimes with a reddish halo, and small red-ringed spots on the fruit skin. Heavy infestations weaken and can kill branches, and the fruit blemishes downgrade the crop. Cause A tiny armored insect called San Jose scale that sits under a waxy cover and sucks sap from the bark. It has several rounds a year. The young, called crawlers, are the only stage that moves around and the only one a spray can hit.San Jose scale (Diaspidiotus perniciosus), an armored scale insect that feeds on sap under a waxy cover. It has several overlapping generations a year; the mobile crawler stage is the point at which it spreads and the only stage a spray reaches. Organic treatment The main control is a good horticultural oil spray while the tree is bare and dormant, coating the twigs and branches to smother the scale. During the season, prune out and destroy any branches that are heavily crusted. Keeping the tree open and vigorous helps.A thorough dormant-season horticultural oil spray, applied to the leafless tree so it coats twigs and scaffolds, smothers overwintering scale and is the mainstay backyard control. In-season, time any additional oil to the crawler stage. Prune out and destroy heavily encrusted wood. Prevention A yearly dormant oil spray in late winter keeps scale from building up. Avoid harsh insecticides so the natural enemies that eat scale can do their work, and keep the tree pruned open so any spray reaches all the bark.An annual dormant oil spray keeps scale from building up. Encourage the tiny parasitic wasps and predatory beetles that attack scale by avoiding broad-spectrum insecticides, and prune to keep the canopy open and easy to cover thoroughly.
Symptoms Ripe apricots have sunken, puckered, dimpled patches, a look growers call catfacing. It comes from insects feeding on the fruit when it was small. 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. The damage is cosmetic on the surface but can run into the flesh; it does not spread or rot on its own. Cause A handful of insects, chiefly stink bugs and the small tarnished plant bug, that poke the young apricots to feed. The spot they feed on stops growing while the rest of the fruit swells around it, leaving a dimple. Because apricots set fruit early, the little fruit is out just as these bugs get going in spring.Several true bugs, mainly stink bugs and the tarnished plant bug, that puncture small apricots to feed. Tissue at each feeding point stops growing while the surrounding flesh keeps swelling, so the mature fruit is left puckered and corky. Apricot ripens early, so the vulnerable young-fruit stage overlaps the spring buildup of these bugs. Organic treatment Spraying a single tree does not help much, because these bugs come in from weeds and brush nearby. The better fix is to take away their hiding spots: mow and pull the broadleaf weeds around the tree, especially in spring while the fruit is small.Spraying one tree does little, since these bugs commute in from nearby weeds and brush. The practical control is to deny them that harborage: mow and clear the broadleaf weeds around the tree, especially through spring when young fruit is most vulnerable. Prevention Keep the ground around the tree mowed and clear of broadleaf weeds, which is where these bugs live and breed. A clean, grassy area around the tree means fewer of them ever reach your apricots.Keep the surrounding ground mowed and free of the broadleaf weeds these bugs breed in; a clean, grassy strip around the tree is the single biggest thing that lowers how many reach the fruit.
Diseases
Symptoms At bloom, flowers go limp and brown and small gummy dead patches form on the nearby spurs. As apricots 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 top. Rotted fruit shrivels into a hard mummy that hangs on. Apricot catches brown rot more easily than almost any other fruit.At bloom, infected blossoms wilt and brown and the infection runs into the spur to form a small gummy canker. As fruit ripens, firm brown spots appear and spread fast, rotting a whole apricot within a day or two in warm, wet weather, with a dusty tan spore mass on the surface. Rotted fruit dries into a clinging mummy. Apricot is among the most brown-rot-susceptible of all stone fruit. Cause A fungus called Monilinia. It survives winter in dried mummy fruit and dead twig patches, then releases spores at bloom that infect the flowers, which later cause the fruit to rot. Warm, wet weather makes it spread fast, which is why apricots do much better in dry-summer climates than in humid ones.The fungus Monilinia (M. fructicola and M. laxa). It overwinters in mummies and twig cankers; spores at bloom infect flowers, and those infections later seed the fruit rot. Warm, humid, wet weather drives it, which is a large part of why apricot is a poor risk in the humid Southeast and better in dry western summers. Organic treatment Cleanup is the main control: take off and destroy every dried mummy from the tree and ground and prune out the gummy dead twig patches, which hold the spores. If bloom is wet, an organic-approved spray at bloom helps protect the flowers. Pick on time, handle gently, and throw out any rotting fruit right away.Sanitation is the core control: remove and destroy every mummy from the tree and ground and prune out gummy twig cankers, since these are the spore sources. In a wet bloom, an organic-approved bloom-time fungicide reduces blossom blight. Pick promptly, handle gently, and remove any rotting fruit at once; an open, fast-drying canopy is a standing defense. Prevention Cleaning up all year prevents most of it: never leave dried mummies over winter, prune so the tree is open and dries fast after rain, and pick on time. In wet climates you will likely need an organic-approved spray at bloom and again near harvest, because apricot is so prone to this disease.Year-round sanitation prevents most loss: never leave mummies over winter, keep the canopy open with pruning so fruit dries fast after rain, harvest promptly, and favor a dry-summer site. In humid regions, plan on a bloom and pre-harvest fungicide program, since apricot's high susceptibility makes sanitation alone insufficient.
Symptoms Sunken, dark, gummy patches (cankers) on the trunk and branches that ooze amber sap, often killing the branch above them. In spring, flowers and buds may blacken and die, and some buds never open. It is one of the worst apricot diseases and hits harder on trees grown on plum rootstocks.Sunken, dark, gummy cankers on trunk, scaffolds, and spurs that ooze amber gum, often girdling and killing limbs; in spring, blossoms and spurs blast (blacken and die) and dormant buds fail to open. It is one of the most serious apricot diseases and is worse on trees grown on plum rootstocks (Myrobalan, Marianna), which are especially susceptible. Cause A bacterium (a microscopic organism) called Pseudomonas syringae. It gets in through wounds, leaf scars, and frost damage during cool, wet weather, and is worse on stressed trees, those in wet soil, hit by frost, or pushed with too much nitrogen. Apricot blooms so early that its tender new growth often meets the cold, wet weather this disease loves.The bacterium Pseudomonas syringae. It infects through wounds, leaf scars, and frost-injured tissue in cool, wet spring and fall weather, and is worsened by anything that stresses the tree: poor drainage, ring nematodes, frost, and high-nitrogen soft growth. Apricot's very early bloom exposes fresh tissue to exactly the cold, wet spells that favor it. Organic treatment There is no cure once it sets in. The approach is prevention: cut out the cankered wood well below the dead patch during dry summer weather (not in wet spring), clean your tools between cuts, and pull out a badly infected young tree. Keep the tree healthy, unstressed, and on well-drained ground; copper sprays only help a little.There is no cure once a tree is infected. Management is preventive: cut out cankered wood well below the canker in dry summer weather (not in wet spring), disinfecting tools between cuts, and remove badly infected young trees. Keep the tree unstressed and well drained; copper sprays give only partial protection and resistance is common. Prevention Prevention is everything: plant where the soil drains well, pick a more resistant rootstock (a peach seedling like Lovell resists it better than plum rootstocks), avoid frosty low spots and trunk wounds, paint the trunk white to prevent sunburn cracks, prune only in dry summer weather, and do not over-feed. A healthy, unstressed tree on good ground shrugs it off best.Prevention is everything: plant on well-drained ground, choose a tolerant rootstock (a peach seedling such as Lovell is more canker-tolerant than the plum stocks), avoid frost-pocket sites and trunk wounds, paint the trunk white against sunscald cracks, prune only in dry summer weather, and never push soft growth with late nitrogen.
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. How badly a tree is hit depends a lot on the variety and on how humid your area is.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. Susceptibility varies by cultivar, and pressure is highest in warm, humid regions. 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 stone-fruit trees close by. Its leaf holes can look like the fungal shot hole disease, which is a different problem.The bacterium Xanthomonas arboricola pv. pruni. It spreads in warm, wet weather and builds up where susceptible stone fruit grow nearby. On apricot the leaf and fruit spotting is sometimes confused with the fungal shot hole (Coryneum blight). 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 and open so the leaves dry fast.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 and the canopy open and dry helps it tolerate the disease. Prevention The best prevention is the variety and the site you pick. A tolerant variety on a spot with dry summers and good airflow avoids most of the trouble, so it is a decision to make before planting. A healthy, open tree also helps.The most effective measure is choosing a resistant or tolerant cultivar and a dry-summer site; this is largely a decision made before the tree goes in. Good airflow, an open canopy, and tree vigor reduce severity.
Symptoms Small reddish-purple spots on the leaves whose brown centers fall out, leaving neat round holes that look like the leaf was hit with birdshot. It also spots the fruit and can kill buds. A bad case drops a lot of leaves and weakens the tree. Apricot is one of its favorite hosts.Small reddish-purple spots on leaves whose centers turn brown, die, and drop out, leaving clean round holes as if shot with birdshot. It also spots the fruit and can kill dormant buds and cause small twig cankers with gumming. Heavy infection defoliates and weakens the tree; apricot is a classic host. Cause A fungus (Coryneum blight) that spends winter in infected buds and twigs and spreads in cool, wet spring weather and wherever water splashes the leaves. Overhead sprinklers that wet the tree make it much worse.The fungus Wilsonomyces carpophilus (Coryneum blight). It overwinters in infected buds and twig lesions and spreads in cool, wet spring weather and by splashing water and overhead irrigation. Wet springs and sprinkler wetting of the canopy drive it. Organic treatment Cut out infected twigs, rake up and destroy fallen spotted leaves, and water at the ground rather than over the top so the leaves stay dry. A copper spray on the bare, dormant tree in late winter is the main way to protect it where this disease is common.Prune out infected twigs and buds, rake and destroy fallen infected leaves, and switch irrigation to the root zone so the canopy stays dry. A dormant application of fixed copper on the leafless tree is the main protective spray where the disease is established. Prevention The biggest thing is keeping the leaves dry: water at the ground, not over the tree, prune so air moves through, and clean up fallen leaves. In wet-spring areas, a copper spray on the bare tree in late winter protects it.Keep water off the canopy (drip or soaker, never overhead), prune for airflow, clear fallen leaves, and apply a dormant copper spray in wet-spring regions. Dry-summer irrigation discipline is the single biggest lever.
