Pear (Asian) in Zone 9 -- plant

Bloom timing & cross-pollination

Pear (Asian)s need a partner

A lone pear (asian) tree sets little or no fruit. Pear (Asian) flowers need pollen from a different variety, carried by bees, and the two trees have to bloom at the same time to trade it. Plant a second variety whose bloom window overlaps, within about 50 feet.

Shinko blooms mid season. 4 varieties overlap and can pollinate it: Kosui, Hosui, Chojuro, Niitaka.Best pick: Chojuro, the strongest bloom overlap of the group.

Bar length shows how long each variety blooms, roughly 8 to 14 days. Bars that overlap can cross-pollinate.

▲ Tap a variety to see its pollination partners

Very early Early Mid Late Very late

Ya Li✓ partner

Tsu Li✓ partner

Shinseiki✓ partner

20th Century✓ partner

Kosui✓ partner

Hosui✓ partner

Chojuro✓ partner

Shinko✓ partner

Niitaka✓ partner

Olympic✓ partner

Seuri✓ partner

The pollination rule

This is the most important thing about growing Asian pears: one tree alone makes only a small, unreliable crop. The flowers need pollen from a DIFFERENT Asian pear variety, carried by bees, so plant two different kinds within about 50 feet that bloom at the same time. A couple of varieties (Shinseiki, 20th Century) can set a small crop on their own, but they do much better with a partner. Two tips: the Chinese kinds (Ya Li, Tsu Li) bloom too early to pollinate the Japanese kinds, so pair them together; and a Bartlett (European) pear can pollinate Asian pears if it blooms at the same time. Once they do set fruit, expect a lot of it, so be ready to thin heavily.Asian pear is only partially self-fruitful: a lone tree, or a single-variety block, sets a light, unreliable crop. Plant two different, compatible Asian pear varieties whose bloom overlaps, within about 50 feet, with bees to move pollen between them. A few cultivars (Shinseiki, 20th Century) are PARTIALLY self-fruitful and set a light crop alone, but even they yield far more with a pollinizer. Two pairing rules: the very-early Chinese pears (Ya Li, Tsu Li) bloom too early to cross the Japanese types, so pair them with each other; and a European pear (Bartlett) can pollinate Japanese Asian pears where their bloom genuinely overlaps. Because the trees also set very heavily once pollinated, plan to thin hard.

In a pot

Yes, on a dwarf rootstock, 20 gallons and up

Only the smallest Asian pear trees do well in pots, the ones grown on a size-controlling rootstock such as OHxF 333 (ask the nursery). A tree on a vigorous betulifolia or calleryana stock quickly gets too big for any pot. Every 2 to 3 years, trim some roots and replace the top few inches of mix. And remember the pollination rule still applies: even a potted Asian pear needs a second, different Asian pear variety blooming nearby to make fruit.Containers suit Asian pear only on a genuinely size-controlling rootstock such as OHxF 333; a betulifolia or calleryana standard tree will outgrow any practical pot. Expect to root-prune and refresh the top few inches of mix every 2 to 3 years to keep the tree productive, and remember a potted Asian pear still needs a bloom-overlapping pollinizer nearby. Containers are the realistic route to pears on a patio without space for two full trees, paired with a second potted variety.

Pot size: 20 gallons and up
Watering: A tree in a pot dries out much faster than one in the ground, so check it every day when it is warm. Stick a finger an inch into the mix; if it feels dry, water until it runs out the holes in the bottom. Empty the saucer so the pot is not sitting in water. The goal is moist mix, never dust-dry and never swampy.Container roots dry out far faster than ground roots, so check moisture daily in warm weather; a 20-gallon pot in summer sun can need water every day or two. Water until it runs from the drainage holes, then let the top inch begin to dry before the next watering. Never let the pot go bone-dry (it drops fruit) and never leave it standing in a full saucer.
Depth and shape: At least 18 inches deep.
Self-watering pot: No. Self-watering (sub-irrigated) containers are not the first choice for pear. They keep the lower rootball continuously moist, and while pear tolerates damp ground better than apple, a permanently wet pot still risks crown rot. Use a free-draining pot with open drainage holes and water from the top.
Mix: Use a high-quality bagged potting mix (a soilless peat- or coir-based medium), not native garden soil or topsoil, which compacts and drains poorly in a container. The mix must be free-draining and stay open over several seasons in the same pot. Blend in roughly 20 to 30 percent compost for nutrition and moisture buffering, and a handful of coarse material such as perlite or fine bark to keep drainage open. Avoid water-holding gels; a potted pear is far more often lost to wet roots than to drought.
Feeding: Frequent watering flushes nutrients from a pot, so a container pear needs feeding somewhat more often than one in the ground, but keep nitrogen modest because of fire blight. Use a balanced slow-release fertilizer at the start of the season and stop by midsummer so the tree hardens off and does not push tender growth into fall.

One to plant on

OHxF 33320 gal pot. OHxF 333 makes the smallest of these trees, about 10 to 14 ft, and resists fire blight and pear decline. It fruits a bit lighter than OHxF 87 but is a great disease-tolerant pick for a smaller yard or a big pot.20 gal pot. OHxF 333 is a semi-dwarfing Old Home x Farmingdale stock, about half to two-thirds standard size, with strong resistance to fire blight, collar rot, and pear decline. Productivity runs a touch lower than OHxF 87, but it is the best size-controlled, disease-tolerant choice for a small yard and works in a large container.

Winter

Winter is the hard part for a potted pear. In a pot, the roots sit above ground and get cold from every side, so they freeze much more easily than roots in the ground. After the leaves drop and the tree is dormant (resting for winter), move the pot somewhere cold but protected, like an unheated garage or shed, or up against the north side of the house. It still needs the cold to rest, but the shelter keeps the roots from freezing solid. Give it a little water now and then so the soil never dries out completely.A potted pear is the winter-vulnerable case: roots in an above-ground pot are exposed to cold from all sides and run several zones less hardy than the same tree in the ground. Once dormant, move the pot to an unheated but sheltered spot (an unheated garage, shed, or against a north wall) where it stays cold enough to hold dormancy but is buffered from the deep-freeze and freeze-thaw swings that kill container roots. Water occasionally so the rootball never fully dries.

Plan winter protection in from the start in cold zones: a pear hardy to zone 4 in the ground may only survive zone 6 or 7 winters in an exposed pot, because the root zone has no insulating soil mass. In order of protection, sink the pot to its rim in the ground for winter, cluster and wrap pots, or move to an unheated sheltered structure. Do not bring a dormant pear into a heated room, warmth breaks dormancy and the tree misses its winter chill.

Hardy to zone 5 in the ground; roots in a pot sit colder than that.

Pot safety

Ask what your balcony or roof can carry

A balcony or roof can only hold so much weight. Before you set heavy pots there, ask a building architect what it can safely carry.Illinois Extension's guidance is to consult a building architect about weight limits before placing heavy pots on a balcony or rooftop garden. It gives no weight figure.

Never grow food in a container with anything toxic in it

Many kinds of containers can be used. Whatever you choose, keep anything toxic out of it, especially if you are growing food.Colorado State accepts nearly any container material but warns against using a container that holds toxic materials, especially for edible plants. Illinois adds that a vegetable container should be free of chemicals toxic to plants or people, and urges caution with treated lumber when growing food. If you cannot account for what a repurposed container once held, that alone is a reason to keep food out of it.

Secure hanging containers well

Fasten hanging baskets and window or rail boxes securely. Think about what is below them too, since they can drip on people or things underneath.Illinois Extension asks growers to secure hanging containers well and to think through the safety issues of hanging them. Placement matters too, since a hanging container can drip onto people or belongings below.

Soil chemistry

Soil pH for pear (asian)

Preferred

6 to 7

Tolerated

5.5 to 7.5

Asian pear trees like soil that runs from slightly acidic to neutral, a pH around 6.0 to 7.0 (pH just measures how acidic or alkaline soil is, where 7.0 is neutral). Test your soil before planting, since it is much easier to adjust the pH now than after the tree is in the ground. Garden lime raises a low pH; garden sulfur lowers a high one. Your local extension office can test a sample for you.Asian pear does best at a pH of about 6.0 to 7.0 and tolerates roughly 5.5 to 7.5. Test the soil before planting and adjust the whole root zone, not just the hole, because correcting pH around an established tree is slow. Lime raises a low pH; elemental sulfur lowers a high one. Well outside this band, iron and manganese availability falls and new growth yellows between the veins.

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Steady hand on the hose

Watering

When & how much

Frequency

Water deeply but not too often, aim for about 1 inch a week while the tree is growing and making fruit. Water more in hot, dry spells and less once the leaves drop in fall.Deep, infrequent irrigation: about 1 inch of water per week through the growing season, more in heat and during fruit sizing, tapering off as the tree goes dormant.

Amount

About 1 inch a week. The easiest way is one long, slow soak that gets the water down deep, rather than a quick daily sprinkle.Roughly 1 inch per week as a baseline (a deep soak that wets the full root zone), increasing during fruit sizing in mid to late summer; pears drop fruit when droughted at sizing.

Method

Use a soaker hose or drip line, or let a hose trickle slowly at the edge of the branches. Keep water off the trunk itself, and mulch around the tree (not touching the trunk) to hold moisture in.Drip or a slow soak at the dripline; keep water off the trunk and crown to avoid collar rot, and mulch to hold moisture (pulled back a few inches from the trunk).

Signs of trouble

Too much water

If the leaves yellow and the ground stays soggy, the tree is getting too much water or the soil drains poorly. Rot at the base of the trunk is a warning sign.Yellowing leaves, persistently soggy soil, and root or collar rot at the trunk base signal too much water or poor drainage; pear tolerates wet ground better than most fruit trees but not standing water.

Too little water

Wilting or dry, brown leaf edges, and small fruit that drops early, mean the tree is too dry, especially in mid to late summer when the pears are filling out.Wilting or scorched leaf margins and premature fruit drop in summer indicate drought stress, especially during fruit sizing.

Feeding rhythm

Feeding

Frequency

annual

Type

balanced

When to start

early spring before bud break

Feed pear trees once a year, in early spring before the buds open, with a balanced fertilizer, and go light. Too much feeding is the number-one pear mistake: it makes lots of soft new growth that the disease fire blight loves, and it pushes the tree to grow leaves instead of fruit. If the tree is growing well and putting out healthy new branches each year, it may need no feeding at all. When in doubt, use less.Feed lightly in early spring before bud break, guided by shoot growth: a healthy young pear makes about 12 to 18 inches of new shoot growth a year, so feed to reach that and no more. Excess nitrogen is the classic pear mistake, it drives soft, succulent growth that fire blight runs straight through, and it delays fruiting. Mature trees on fertile soil often need no nitrogen at all. If anything, err on the side of underfeeding a pear.

N · P · K = 10-10-10

The three numbers on a fertilizer bag are nitrogen, phosphorus, and potassium. A balanced one like 10-10-10 is fine for pears, used sparingly. The first number (nitrogen) is the one to keep low, because too much makes soft growth that catches fire blight.A balanced N-P-K ratio (the three numbers on the bag, nitrogen, phosphorus, potassium) such as 10-10-10 at a modest rate, leaning toward the low end on any vigorous tree to limit fire-blight-prone growth. On fertile ground a pear often wants none.

Who grows well together

Companion planting

Pears do not pair with other plants the way vegetables do. For an Asian pear, the neighbor that counts is a second, different Asian pear variety that blooms at the same time, within about 50 to 100 ft, because most Asian pears need another Asian pear nearby to make fruit. Right around the trunk, do the opposite of planting companions: keep grass and other plants away from the base out to the edge of the branches, because they steal water and food from the young tree. Use mulch there instead, and never plant an Asian pear near a black walnut tree, which poisons the soil for it. Pear does not companion-plant in the vegetable sense; the interactions that matter are pollination and root competition. The single most important neighbor is a second, bloom-overlapping Asian pear variety (the pollinizer) within about 50 to 100 ft, since most Asian pears are self-unfruitful. At the trunk, the rule reverses: keep turf and aggressive perennials out of the root zone, where grass competes hard with a young tree for water and nitrogen. Maintain a mulched, vegetation-free circle to the dripline, and avoid siting near black walnut, whose juglone is toxic to Asian pear.

Pest deterrent

spring bulbs (daffodil)

Plant a ring of daffodils around your pear tree, out where the branches reach. They come up early in spring, help keep grass from creeping toward the trunk, and because they are poisonous to nibble, they discourage mice and deer. They die back in summer, so they stay out of the tree's way.A ring of daffodils at the drip line is a traditional fruit-tree-guild move with two intended jobs: the early foliage forms a band that helps hold back creeping grass, the tree's main competitor, and daffodils are toxic enough that voles and deer tend to avoid grazing through them to the trunk. They emerge and feed before the canopy leafs out, then go dormant, so they do not compete in summer. Treat this as a useful cultural barrier rather than a measured yield booster. Traditional

Nutrient

comfrey

Comfrey is a leafy plant that grows well around fruit trees. Its roots reach deep down, so it does not steal water from the tree, and it crowds out grass. A few times each summer you can cut the big leaves and lay them on the soil under the tree, where they rot down into natural food for it. Its flowers also bring in helpful bees.Comfrey is a workhorse of the fruit-tree guild. Its deep taproot pulls from well below the tree's surface feeder roots, so it does not compete for the same water and nutrients, and it shades out grass along the row. Chopped two or three times a season and dropped under the tree, its lush leaves break down into a mineral-rich mulch, and the flowers feed pollinators. The dynamic-accumulator framing is more tradition than proven chemistry, but the practical value as non-competing mulch and grass suppression is real. Traditional

Ground cover

clover (living mulch)

White clover is a low, soft plant you can grow as a living carpet under your pear tree. It pulls nitrogen from the air and feeds it slowly into the soil, while covering the ground to keep weeds down and hold in moisture. It is tough enough to walk on at picking time. Just keep it from growing right against the trunk.Dutch white clover makes a strong living mulch under pears. As a legume it fixes atmospheric nitrogen through its root symbiosis, feeding the tree slowly while staying low and tolerating harvest foot traffic. It covers the ground to suppress weeds and hold moisture without the aggressive grass competition bare turf brings. Keep it back from the immediate trunk zone, and note it does draw some moisture, so manage it on dry sites. Because pears want lean nitrogen, treat the clover's slow trickle as a feature, not a reason to also fertilize. Well-grounded

Keep apart from

black walnut Keep pear trees far away from black walnut trees. Black walnuts release a natural chemical called juglone from their roots and leaves that is poisonous to pears and can make them sicken and die. The chemical spreads through the soil well past the walnut's branches, so give them a very wide berth, at least 50 feet from a big walnut.Black walnut is a definitive bad neighbor for pear. Its roots, hulls, and leaf litter release juglone, an allelopathic compound toxic to many sensitive plants, and pear (like apple) is among those affected, showing decline and dieback within the walnut's root zone. The effect extends well beyond the visible canopy, roughly to the full root spread (commonly cited at fifty-plus feet from a mature tree), so siting matters more than spacing tweaks: keep pears entirely out of a black walnut's root zone. Well-grounded

turfgrass to the trunk Do not let lawn grass grow right up against your pear tree's trunk. The grass competes with the young tree for water and food, so it grows slower and fruits later. Grass at the trunk also hides mice that can chew the bark in winter. Keep a clear or mulched circle about two feet around the trunk, with the mulch pulled back slightly so it does not touch the bark.Letting turfgrass grow right up to a pear trunk is a quiet but real drag on the tree, especially when young. Grass competes directly for water and nitrogen in the surface zone where the feeder roots sit, slowing growth and delaying bearing, and dense grass and mulch against the trunk harbor voles that girdle bark over winter. Maintain a vegetation-free or mulched strip about two feet out from the trunk (mulch pulled back a few inches off the bark itself). Research-backed

Provenance tagged inline · see methodology for the labeling system Key

Harvest signals

When to pick

An Asian pear is ready to pick when it is ready to EAT, because it ripens on the tree, not off it (the reverse of a European pear). Look for the skin to reach full color: green turning yellow on the smooth kinds, or green turning golden-brown on the russet kinds. Then taste one, it should be sweet, crisp, and juicy, like a very juicy apple. If it is hard and bland, leave the rest on the tree to finish, because they will not sweeten indoors. Handle them gently so they do not bruise. Do not expect a real crop until about the third to fifth year after planting.Asian pears ripen ON the tree and are picked tree-ripe, the opposite of European pears: the fruit sweetens only on the branch and does not finish ripening off it. Pick when the skin has turned full varietal color (green to yellow on smooth types like 20th Century and Shinseiki, green to golden-brown or bronze on russet types like Hosui, Chojuro, and Shinko), the fruit parts easily from the spur on a gentle upward twist, and a taste test is sweet, crisp, and juicy. Taste is the surest guide, so sample a couple of test fruit before stripping the tree. Asian pears hold on the tree for a few weeks and are eaten firm and crisp like an apple. First meaningful crop typically comes around year 3 to 5, rootstock-dependent.

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Yield

What to expect

Asian pears set a lot of fruit. A smaller tree gives roughly 1 to 3 bushels a year (a bushel is about 40 lb), and a full-size tree gives much more. Because they set so heavily, you must thin off a lot of the young fruit, or you get many tiny, gritty pears and broken branches.Mature yield is rootstock-driven and Asian pears crop heavily: a size-controlled tree (OHxF 333 or 87) carries roughly 1 to 3 bushels (about 40 to 120 lb) per year, and a vigorous betulifolia or calleryana standard can far exceed that at full maturity. The heavy natural set is the reason aggressive thinning is essential, unthinned trees make many small, gritty fruit and break limbs.

An Asian pear builds up to full production over several years after its first crop, a bit faster than a European pear. Some varieties swing between a big year and a small year; thinning the young fruit hard every year helps keep crops steadier.Trees reach full bearing several years after first crop, roughly years 5 to 8, sooner than a European pear and sooner still on a size-controlling rootstock. Many cultivars tend toward biennial bearing (a heavy year then a light one); consistent hard thinning evens it out. Expect zero pears the first year, that is normal and intended. Your first real handful of fruit usually comes around year 3 to 5, a little sooner than a European pear.No crop in the planting year (blossoms are removed). First meaningful fruit around year 3 to 5, rootstock-dependent and a bit earlier than a European pear.

What changes yield

rootstock (sets tree size, bearing age, and fire-blight/decline tolerance)cross-pollination success (a compatible, overlapping pollinizer within ~50 ft)hard fruit thinning (Asian pears over-set; thinning drives size and curbs biennial bearing)late-frost damage to the early bloomfire blight, pear psylla, and stink bug pressure

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Off the vine

Storing your harvest

Room temp

Asian pears are ready to eat straight off the tree, crisp and sweet. On the counter they keep about a week.Asian pears are picked tree-ripe and eaten crisp, so unlike European pears they need no ripening rest. At room temperature a ripe Asian pear holds about a week, staying firm and juicy; eat the softest first.

Fridge

In the fridge, Asian pears last a long time, often 1 to 3 months, and stay crisp. Take one out and eat it cold whenever you like, no waiting for it to soften.Refrigerated near 32 to 34°F at high humidity, Asian pears store unusually well for a pear: most cultivars keep 1 to 3 months and stay crisp, and the late russet keepers (Chojuro, Shinko, Olympic) hold longest. They are ready to eat cold, with no ripening step needed.

Freezer

Frozen whole, Asian pears go mushy and lose their crunch. Slice them into a little light syrup or cook them down first, then freeze; they keep about a year.Asian pears are watery and lose their signature crunch when frozen whole; freeze them as slices in light syrup or as sauce for cooking use up to about a year.

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When something goes wrong

Common problems

Lots of flowers, but no pearsTree flowered but set no fruit

01 of 06

What happened Your tree flowered but the blossoms fell without making pears. Usually there was no second, compatible Asian pear variety blooming nearby. Watch for two traps: the Chinese kinds (Ya Li, Tsu Li) bloom too early to match the Japanese kinds, and Niitaka cannot pollinate well.Without a compatible pollinizer in overlapping bloom within about 50 ft, Asian pear blossoms are not fertilized and drop. Common traps: two of the same cultivar, a Chinese pear (Ya Li, Tsu Li) whose early bloom never overlaps the Japanese types, or relying on Niitaka, whose pollen is a weak partner. Next season Plant a second, different Asian pear that blooms at the same time and is a compatible match, within about 50 ft. Pair Chinese kinds together and Japanese kinds together, or use a Bartlett pear that blooms at the same time.Add a second, genetically different, COMPATIBLE Asian pear whose bloom overlaps, within about 50 ft (pair Chinese with Chinese, Japanese with Japanese). A European pear like Bartlett can also pollinate Japanese types where bloom overlaps.

Branches turned black, as if burnedBranch tips blackened and scorched

02 of 06

What happened Branch tips suddenly turned black and bent into a hook, as if scorched. This is fire blight, the main pear disease, which spreads in warm, wet weather and loves the soft growth from too much fertilizer.Fire blight (Erwinia amylovora) infected through blossoms or tender shoots in warm, wet weather, blackening shoots into shepherd's crooks and forming cankers. Asian pear is highly susceptible (20th Century and Niitaka worst), and lush nitrogen-pushed growth made it worse. Next season Cut the blackened branches well below the damage in dry weather, wiping tools between cuts. Next time choose a more resistant variety (Shinko, Chojuro), go easy on fertilizer, and only prune when it is dry.Cut out infected wood 8 to 12 inches below symptoms in dry weather, disinfecting between cuts; going forward plant more resistant cultivars (Shinko, Chojuro) on a tolerant rootstock (OHxF or calleryana) and keep nitrogen lean.

Pears hard and flavorless, never sweetenedPears hard, starchy, and bland

03 of 06

What happened You picked the pears too early and they never got sweet. Asian pears only ripen on the tree, so once they are picked hard, they stay hard and bland indoors.The fruit was picked before it was tree-ripe. Unlike European pears, Asian pears sweeten only on the tree and do not finish ripening off it, so an early-picked pear stays hard, low-sugar, and starchy no matter how long it sits on the counter. Next season Leave them on the tree until they are fully colored and taste sweet and crisp, then pick. There is no rush, they hang on the tree for weeks.Let them ripen on the tree and pick tree-ripe: wait for full varietal color and taste-test for sweetness and crispness before harvesting. They hold on the tree for a few weeks, so there is time to get it right.

Lots of tiny, gritty fruitMany small, gritty pears and sagging limbs

04 of 06

What happened The tree made a huge number of tiny, gritty pears, and the branches sagged or broke. Asian pears set far too much fruit on their own and were not thinned.Asian pears set very heavily, and the fruit was not thinned, so the tree carried a huge number of small, stone-celled (gritty) pears and risked breaking limbs. Over-cropping also pushes the tree toward biennial bearing (a heavy year then a bare one). Next season Thin the young pears hard, about a month after bloom: leave just one per cluster, spaced roughly a hand-width apart. You lose a lot of little fruit but get big, good ones and protect the branches.Thin hard within 4 to 6 weeks of bloom, to one fruit per cluster and roughly 6 inches apart. Fewer fruit means larger, less gritty pears, less limb breakage, and steadier annual bearing.

Few flowers, or flowers very lateSparse, delayed, or straggly bloom

05 of 06

What happened The tree barely flowered, or flowered oddly late and patchy. This usually means the variety needs more winter cold than your area gives, and pears need more cold than apples.A higher-chill cultivar grown in a warm-winter zone did not accumulate enough chill to break dormancy normally, giving delayed, uneven, weak bloom and poor set. Asian pears need only moderate chill, so the mismatch is easy to avoid with the right variety. Next season Pick a low-chill Asian pear suited to mild winters, like Shinseiki or Ya Li. The right variety for your climate flowers normally.Match variety chill to your winters: in warm zones choose low-chill cultivars (Shinseiki, Ya Li).

Sticky, blackened leaves and shootsSticky leaves with black sooty mold

06 of 06

What happened The leaves and young pears got coated in sticky goo that turned black and grimy. That is pear psylla, a pear-specific insect; it gets worse if harsh sprays have killed the helpful bugs.Pear psylla nymphs fed heavily and exuded honeydew that grew black sooty mold, scorching leaves and russeting fruit. Outbreaks often follow broad-spectrum sprays that kill the psylla's natural enemies. Next season Spray dormant oil in late winter to smother the overwintering insects, use insecticidal soap during the season, and avoid harsh sprays that kill the good bugs.Apply dormant oil in late winter, use insecticidal soap or summer oil in season, and conserve natural enemies by avoiding broad-spectrum insecticides.

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The usual suspects

Pests & diseases

Pests

Codling moth

P · 01

Symptoms This is the classic 'worm in the fruit.' You find a small hole with brown crumbly stuff (frass) around it, and a tunnel into the core when you cut it open. Bad pears drop early.Larvae tunnel to the core and feed in the seed cavity, leaving one or more holes plugged with frass on the fruit surface; a shallow sting where a larva bored a short way and died is the other mark. Check where two fruits touch, a common entry point. Infested pears drop early or are inedible. Cause A small moth lays eggs on the tiny pears in spring; the eggs hatch into caterpillars that crawl into the fruit. There can be two batches a summer, so the problem repeats.Cydia pomonella; females lay eggs singly on leaves and on fruit, and the hatching larvae bore into the pear. It overwinters as a full-grown larva in a silken cocoon under loose bark scales or in soil and debris at the base of the tree, and depending on climate has two, three or sometimes four generations a year. The same pest attacks apple and English walnut. Organic treatment Pick up and throw away every pear that drops, do not leave them under the tree. You can slip paper bags over young pears to keep moths out, and scent traps help you know when to act. Sprays like spinosad work if timed right.Monitor with pheromone traps and a degree-day count to time control to egg hatch; remove infested fruit from the tree and dropped fruit promptly; bag fruit four to six weeks after bloom, the one nonchemical measure UC IPM rates as effective alone; spinosad at egg hatch, three sprays at 10-day intervals for the first generation and no more than six per season; a codling moth granulosis virus (CYD-X) applied weekly through hatch where available. Mating disruption is an orchard-scale tool. Prevention Keep the ground under the tree clear of fallen pears, and pull off any pear with a hole in it before the caterpillar inside can leave. Thin to one pear per cluster. A cardboard band around the trunk is an old trick UC IPM no longer recommends for home trees, because it catches very few of the caterpillars and can make things worse if you forget to take it down. An abandoned pear or apple tree nearby keeps the moths coming, so take it out if it is yours.Sanitation from the first flight on: pick infested fruit off the tree before the larvae mature, clear drops as they fall, thin to one fruit per cluster and inspect touching fruit. Remove, rather than prune, any abandoned apple, pear or walnut nearby, which UC IPM treats as a reservoir. Cardboard trunk bands are no longer recommended for home gardens: they catch only a small share of the larvae, and a band not removed in time breeds moths.

The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

Garden sanitation

Check the young pears every week or so and pull off any with a small hole ringed by brown crumbs, then pick up every pear that drops as soon as you see it, because the caterpillar is usually still inside and will crawl out to start the next batch. Thin to one pear per cluster and look closely where two fruits touch, a favorite spot for the hole. Destroy what you collect rather than leaving it under the tree.Cydia pomonella overwinters as a mature larva in a silken cocoon under loose bark scales and in soil or litter at the base of the tree, and every larva that leaves a pear to spin one is a moth next flight, so an infested fruit taken off the tree or a drop picked up promptly is a moth that never flies. UC IPM is blunt that it is far easier to hold numbers low from the first flight than to pull down a population that has built for a season or two. Thin to one fruit per cluster, inspect the contact point of touching fruit, and take out any abandoned apple, pear or walnut nearby, which UC IPM's pear guideline treats as a reservoir to remove.
Codling moth pheromone trap

Hang a scent trap in the tree in spring. It catches male moths, and its real job is to tell you the moths have started flying, which sets the clock for bagging the fruit and for any spray. On its own it will not keep the pears clean.A pheromone-baited trap marks first sustained male flight, and UC IPM's home guidance keys the first spray to egg hatch, which follows the first regular catches by a run of warm days that its guide gives as a heat-unit count rather than a calendar date; counts through summer flag the second and any third generation. Hanging traps in every tree may thin an isolated tree's moths slightly, but UC IPM does not rate that as a reliable way to reduce damage, so read the trap as a calendar rather than a control.
Fruit bagging

Once the flowers have dropped and the young pears are half an inch to an inch across, roughly four to six weeks after bloom, enclose each one in a paper bag fastened around the stem. A bagged pear is out of the moth's reach, so no egg is laid on it and no caterpillar gets in. It takes time per fruit, so it fits a tree with a crop you can count.This is the one nonchemical measure UC IPM rates effective enough to stand alone even under heavy pressure, and it earns that by taking the fruit out of the egg-laying site altogether rather than trimming the population. The window is four to six weeks after bloom at 1/2 to 1 inch fruit, and NC State's handbook gives the same span; thin to a single fruit per cluster first, and bag early on late-developing varieties, which UC IPM warns can be attacked before the fruit reaches 1/2 inch.
Spinosad

If the tree carries more fruit than you can bag, spinosad is the organic spray UC IPM lists for home trees, and timing is everything: the first spray goes on as the first caterpillars hatch, before they bore in, with two more at ten-day spacing, and never more than six in a season. It is hard on bees while wet, so spray at dusk and keep it off anything in flower, and stop at least a week before you pick.Spinosad, a fermentation product of Saccharopolyspora spinosa, kills young larvae by ingestion and contact, so it has to be on the fruit surface as eggs hatch; UC IPM's home schedule is three sprays at 10-day intervals from first-generation hatch, a season cap of six, and a 7-day preharvest interval. Place the first spray with the trap and degree-day count, since a spray before hatch is wasted and one after the larva has entered the pear is useless. UC IPM also names a granulosis virus (CYD-X) sold to California home gardeners that affects only codling moth larvae and, applied weekly through hatch, matched carbaryl in its trials.
Carbaryl

Carbaryl is the old-style chemical UC IPM measures the softer options against, and it works, but at a real cost: it kills bees and the helpful insects along with the moths, so it must never go on a tree in bloom or when bees are working it, and on a pear it can set off an outbreak of pear psylla by wiping out the insects that keep psylla down. Keep it for a tree where bagging and spinosad have not held the damage, and read the label's waiting time before harvest.UC IPM's home note gives carbaryl a 14-to-21-day residual against codling moth and calls it very disruptive to natural enemies and honey bees, with an absolute bar on spraying during bloom or when bees are present. On pear the secondary cost is specific: UC IPM's pear guideline attributes psylla outbreaks to nonselective codling moth insecticides destroying the predators and parasites that hold psylla in check, so a carbaryl program for the moth can buy a sticky, sooty tree by late summer. It also carries a carcinogen listing, which on a food crop is the reason to exhaust the other measures first.

No spray for this one. Prevention is the control.

Pear psylla

P · 02

Symptoms Leaves and young pears get coated in a sticky, shiny film that turns black and grimy (sooty mold), and the leaves may scorch and drop. Tiny insects cluster on the new shoots.Nymphs feed in clusters on shoots and leaves and exude sticky honeydew that blackens with sooty mold; heavy feeding blackens and scorches leaves, drops them early, russets the fruit, and in large numbers stunts the tree and drops fruit, the reaction WSU calls psylla shock. It is a greater problem on European pears than on Asian pears. Cause A tiny pear-specific insect (a kind of jumping plant louse) that sucks sap and oozes sticky stuff. It can build up fast, especially if bug sprays have wiped out the good bugs that normally keep it down.Cacopsylla pyricola; a small psyllid specific to pear that overwinters as an adult and builds several overlapping generations through the season. Outbreaks follow broad-spectrum sprays that kill its natural enemies. Organic treatment Spray horticultural oil while the tree is bare and before the buds swell, to smother the adults that lived through winter on the bark; it will not kill eggs already laid, so do not wait. In the growing season use insecticidal soap, kaolin or neem on the new shoots. Avoid harsh sprays, including strong sprays aimed at codling moth, because they kill the helpful bugs that eat psylla.Horticultural oil at least once in the dormant season, before buds swell, and again just before bloom if last year was bad: oil kills overwintered adults and discourages egg laying but does not control eggs. In season, insecticidal soap, kaolin or neem on the new growth; conserve natural enemies (Anthocoris and other predatory bugs, lacewings, the parasitic wasp Trechnites) by keeping broad-spectrum insecticides, including those aimed at codling moth, off the tree; kaolin before bloom to deter colonization and egg laying. Prevention A dormant oil spray while the tree is bare and before the buds swell, and going easy on harsh sprays and fertilizer, keep this pear pest in check.A well-timed dormant oil program plus a natural-enemy-friendly spray regime is the backbone of psylla management; avoid the lush nitrogen-pushed growth psylla favors.

The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

Balance nitrogen

Feed the tree modestly and do not chase big flushes of soft new growth, because that sappy growth is what pear psylla settle on and breed in. WSU's home fact sheet puts it simply: prune lightly, give moderate nitrogen, and cut out the water sprouts and suckers that psylla favor.Psylla nymphs feed on succulent shoot tissue, so vigor management is a population lever: WSU's Hortsense guidance is to prune lightly, supply moderate amounts of nitrogen, and remove water sprouts and suckers, which strips out the flush growth that carries the heaviest nymph loads and honeydew. The light-pruning instruction is the other half of the same idea, since hard cuts provoke exactly the regrowth psylla wants.
Kaolin clay

A coat of kaolin clay, the white mineral spray, makes the tree an unattractive place for psylla to land and lay eggs. WSU's home fact sheet lists it among the growing-season options, and it does most good put on before bloom, when the overwintered adults are starting to lay. Rain washes it off, so it needs renewing, and the white film has to be rinsed off the fruit at harvest.Kaolin is a particle film that reduces adult colonization and egg laying rather than killing nymphs already feeding, which is why UC IPM's pear guideline places it prebloom and WSU's orchard program reports 80 to 100 percent less colonization and egg lay, cutting first-generation pressure. UC IPM warns that later-season use may cause mite outbreaks, and heavy use can set back beneficials, so on a home tree it is a spring measure rather than a summer one.
Beneficial predators

Lacewings, lady beetles and small predatory bugs eat pear psylla for free, and they are a large part of why a lightly managed tree rarely has a serious problem. The way to keep them is to not spray anything broad-spectrum on the tree, including the sprays aimed at codling moth, because UC IPM traces psylla outbreaks straight to those sprays killing off the helpers.Cacopsylla pyricola is held in check by a resident complex WSU names as the parasitic wasp Trechnites insidiosus, the predatory bugs Deraeocoris brevis, Campylomma verbasci and Anthocoris spp., green and brown lacewings, and the European earwig; UC IPM's pear guideline states that nonselective codling moth insecticides destroy many of these beneficials and produce outbreaks. On a home tree the decision is therefore made on the codling moth side: bag the fruit or use a selective material there, and the psylla largely looks after itself, which matters doubly on an Asian pear, where UC IPM rates psylla a lesser problem than on European varieties.
Horticultural oil

The backbone spray is horticultural oil while the tree is bare, put on before the buds swell, because the adults that lived through winter in bark cracks and litter around the tree are on the wood then and the oil smothers them. UC IPM says to apply it at least once in the dormant season, and to repeat just before bloom if psylla were bad the year before. Oil kills the adults; it does not kill eggs already laid, which is why the timing is early.Adults overwinter in bark crevices, under bark scales and in litter at the base of the tree and begin ovipositing at bud swell, so a dormant oil hits the population at its narrowest point; UC IPM's pear guideline is explicit that oil kills adult psylla but does not control eggs, though it discourages egg laying for about a month, which is why the home timing is at least one application in the dormant season with a second just before bloom in a bad year. Coverage of the wood is the whole job, and oil is not applied in heat or to a water-stressed tree.
Insecticidal soap

During the growing season, insecticidal soap sprayed onto the shoots where the small nymphs and their sticky honeydew are will kill what it wets and nothing else. It has no lasting effect, so repeat as new nymphs appear, spray early morning or late evening, and WSU says a homeowner should not be spraying a tree taller than 10 feet at all.Potassium salts of fatty acids work only on contact with soft-bodied nymphs, and psylla nymphs sit in honeydew on leaf undersides and in shoot tips, so coverage of the new growth decides the result; WSU's home fact sheet and Oregon State's home orchard calendar both list soap from prepink through summer. It spares the predator complex once dry, which is what makes it the in-season material over anything broad-spectrum, and WSU's rules apply: morning or evening timing, and no foliar sprays on trees over 10 feet.

No spray for this one. Prevention is the control.

Stink bug

P · 03

Symptoms Stink bugs poke the growing pears to feed, leaving dented, lumpy fruit with hard brown corky spots inside. The outside can look mostly fine while the flesh underneath is pitted and dry.Stink bugs, including the invasive brown marmorated stink bug, pierce developing fruit to feed, leaving dimpled, catfaced pears with hard, corky, pithy brown patches in the flesh under each feeding site. The skin often looks nearly normal while the interior is pitted. Worst near weedy field and woodland borders. Cause Shield-shaped bugs, including an invasive kind called the brown marmorated stink bug, that suck on the fruit through the season. They move in from nearby weeds, fields, and woods.Several native stink bugs (the consperse stink bug, Euschistus conspersus, and relatives) plus the invasive brown marmorated stink bug (Halyomorpha halys). Brown marmorated adults overwinter in sheltered places, including houses and sheds, emerge in spring and move straight onto available hosts; the natives overwinter in ground litter. Adults and nymphs both feed on the fruit into harvest, moving in from weeds, neighboring crops and woodland edges, and late feeding may not show until the fruit has been stored. Organic treatment Coating the fruit with kaolin clay (a fine white clay spray) helps keep them off, and clearing weeds and rough grass around the tree in early spring removes the place they build up. Look under the leaves for the clusters of eggs and the bunches of small nymphs and squash them. A small tree can be covered with fine mesh once the fruit has set. Sprays are a poor answer for these bugs; by the time you see the damage they have usually moved on.Kaolin clay suppresses feeding; eliminate weeds and groundcover in early spring before the bugs build up in them; pick and destroy egg masses and groups of young nymphs, by hand, net or shaking; screen a small tree with a floating row cover or similar barrier after fruit set where practical; conserve natural enemies by avoiding broad-spectrum sprays. Insecticides are generally not recommended for stink bugs in gardens, since the damage shows after the bugs have gone; the home products WSU lists work best on very young nymphs, are not recommended against adults, and are toxic to bees. Prevention Clear the weeds and rough growth around the tree in early spring, before the bugs move into it, and keep it down all season. Go easy on strong bug sprays so the spiders and predatory bugs that eat stink bug eggs stay around. If they ruin the fruit every year on a small tree, cover it with fine mesh once the fruit has set.Eliminate weeds and herbaceous groundcover in early spring before stink bugs become abundant in them, and keep them down through the season; reduce broad-spectrum insecticide use so parasitic wasps, big-eyed bugs, assassin bugs, damsel bugs and crab spiders keep populations in check. Where damage recurs on a small tree, screen it after fruit set.

The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

Weed host control

Stink bugs build up on weeds and rough grass around the tree and then move onto the pears, so clear that growth in early spring, before they get numerous in it, and keep the ground under and around the tree clean through summer. Timing is the point: UC IPM says to take the weeds out before the bugs are abundant in them, not after.NC State's handbook calls weeds the primary food source for the catfacing bugs, and UC IPM's instruction is to eliminate groundcovers and herbaceous weeds in early spring before stink bugs become abundant in them and move to alternative hosts. The brown marmorated stink bug is an edge invader that WSU and Rutgers both record moving in from wooded borders and neighboring crops, so on a home tree the reach of this measure is the ground you control; it lowers what arrives rather than what is already on the fruit.
Handpick

On branches you can reach, look under the leaves for the clusters of 20 to 30 pale barrel-shaped eggs and the groups of small nymphs that hatch from them, and crush them or drop them into soapy water. WSU's pear fact sheet recommends exactly this, and it works because the young bugs stay bunched together after hatching.Halyomorpha halys lays eggs in groups of about 20 to 30 on leaf undersides and the early nymphs feed in a cluster, which is the stage that hand removal, net-sweeping or shaking a branch over a tray actually reaches; WSU lists all three. Adults are strong fliers that arrive from outside and leave again, and UC IPM notes the feeding damage often shows only after the bugs have gone, so hand removal is aimed at the egg masses and nymph groups, not at chasing adults.
Floating row cover

On a small or dwarf tree, WSU says a floating row cover or similar fine barrier over the canopy can keep stink bugs off the fruit where that is practical. Put it on after the flowers are finished and the fruit has set, because a cover shuts out the bees the tree needs, and take it off to pick.WSU's pear guidance allows screening plants with a floating row cover or similar barrier when practical, and on a tree that means a dwarf on a small frame rather than a standard; the barrier has to be sealed at the ground and go on after pollination, since pears need cross-pollination and the same mesh excludes the bees. It is the exclusion measure WSU names for this pest on pear; bagging individual fruit is not on any page read for stink bug.
Kaolin clay

A kaolin clay coating on the fruit and leaves makes the pears an unpleasant surface for stink bugs to feed on and less attractive to land on. Oregon State's home orchard guide lists it for brown marmorated stink bug, but only as suppression, so expect fewer dimpled pears rather than none, and renew it after rain.Kaolin is a repellent film rather than a toxicant, and Oregon State's EC 631 lists it against brown marmorated stink bug on pear with the explicit qualifier suppression, which is the right expectation for a bug that flies in from the edge as an adult and probes rather than chews. Coverage of the fruit surface is what counts, so reapply as the fruit sizes and after rain, and wash the residue off at harvest.
Beneficial predators

Big-eyed bugs, assassin bugs, damsel bugs, crab spiders and several tiny wasps that attack stink bug eggs are already in most gardens, and NC State says the way to keep them working is to cut back on broad-spectrum sprays. They will not give complete control on their own, WSU is clear about that, but they are part of why a lightly sprayed tree has fewer.NC State names parasitic wasps, big-eyed bugs, assassin bugs, damsel bugs and crab spiders as the resident enemies of the catfacing bugs, and its instruction is to reduce broad-spectrum insecticide use so they keep pest populations in check; WSU adds that natural enemies may not be sufficient for complete control of the brown marmorated stink bug but that broad-spectrum sprays should still be avoided for their sake. It is also why a spray is a poor answer here: UC IPM says insecticides are generally not recommended for stink bugs in gardens because the damage appears after the bugs have left, and WSU rates its listed home products as toxic to bees and not recommended against adults.

No spray for this one. Prevention is the control.

Diseases

Fire blight

D · 01

Symptoms Branch tips and flower clusters suddenly turn black and look burned, as if scorched by fire, and the tip bends over into a hook. It can kill whole branches or the whole tree. Asian pears catch it easily.Blossoms and shoot tips suddenly wilt, blacken, and die, bending into a characteristic shepherd's-crook; affected branches look scorched, and sunken, oozing cankers form on wood. Most Asian pears are very susceptible, Shinko excepted, with Twentieth Century (Nijisseiki) rated highly susceptible; warm, wet weather at bloom drives the worst outbreaks, and the younger the tree, the more likely it dies. Cause Bacteria that infect through the flowers and soft new shoots in warm, wet spring weather. Fast, soft growth from too much fertilizer makes it much worse. Once a tree has it, it keeps it, and Clemson calls it the biggest problem there is in growing Asian pears.Erwinia amylovora; bacteria infect through open blossoms and tender shoot tips when the weather is rainy or humid with days of 75 to 85°F and nights above 55°F, and spread fastest on lush, nitrogen-pushed growth. Once infected, a tree harbors the bacterium indefinitely, and Clemson calls fire blight the most significant problem limiting the production of Asian pears. Organic treatment Cut off the blackened branches well below the damage, at least 12 inches back into clean wood (Clemson's Asian pear guide says 18 inches), wiping your pruners with a 1-to-9 bleach mix or rubbing alcohol between cuts, and only in dry weather. Do the main cutting in winter while the tree is dormant, but a strike that is racing down a branch in spring should come off as soon as you see it. Burn or bury what you cut. There is no spray that cures it.Prune out infected wood at least 8 to 12 inches below visible symptoms (Purdue and OSU say 12, WSU 12 to 18 in older wood, Clemson's Asian pear guide 18), cutting at the next branch juncture below the infection, in dry weather, with tools dipped in 10 percent bleach or 70 percent alcohol between cuts; cut placement matters more than tool sterilization. Do the main removal in the dormant season, when pruning cannot spread the bacteria, but cut rapidly advancing spring strikes at once. Remove a tree with more than half its canopy blighted. There is no cure once established; management is prevention plus cutting it out. Prevention The best defense is to choose a more resistant variety (Shinko, Chojuro) on a resistant rootstock, especially where summers are warm and humid. Then go easy on fertilizer (soft growth catches it) and prune only in dry weather.The decisive moves are cultivar and rootstock choice: plant the more resistant Asian pears (Shinko first, then Chojuro, Seuri, Olympic, Shin Li) on a fire-blight-resistant rootstock (Old Home x Farmingdale, or the birchleaf pear Pyrus betulifolia that Clemson recommends for Asian pears). Then avoid excess nitrogen and heavy pruning, which push the succulent growth that gets infected, do not irrigate during bloom, and cut out blight in the dormant season. Copper at bloom is a partial protectant, the only material UC IPM lists for California home growers; Purdue and Clemson also describe streptomycin during bloom for home use, where it can be obtained, capped by Purdue at three to four sprays a season.

The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

Resistant varieties

Clemson calls fire blight the most significant problem limiting Asian pears, and the biggest decision is made when you buy the tree. Shinko is the most resistant by every guide, with Chojuro, Seuri, Olympic (also sold as Korean Giant) and Shin Li showing some resistance; Twentieth Century (Nijisseiki) is highly susceptible. Buy it on a fire-blight-resistant root too: Clemson recommends the birchleaf pear (Pyrus betulifolia) for Asian pears, and the Old Home x Farmingdale rootstocks resist it as well.Resistance is partial, not immunity, and the ratings disagree at the margins: Shinko heads every list (Clemson's best, Purdue resistant, UC IPM's lone Asian exception); Purdue also rates Chojuro, Kosui, Olympic, Seuri, Shinsui, Singo and Tse Li resistant and Hosui, Kikusui, Okusankichi, Seigyoku, Twentieth Century and Shinseiki susceptible, while Clemson's two fact sheets split on Hosui, which gets planted anyway as Shinko's pollinizer. Rootstock is a separate layer: Purdue lists Old Home x Farmingdale (except OHxF 51) and Pyrus betulifolia seedlings as resistant and Bartlett seedling as susceptible, and Clemson notes betulifolia is vigorous and throws thorny root sprouts. Clemson puts cultivar choice in the same sentence as sanitation and avoiding excess nitrogen, because succulent growth is what gets infected.
Prune out infection

No spray cures fire blight, so cutting it out is the treatment. Take each blackened shoot or branch back at least 12 inches below the last sign of damage into clean wood, and Clemson's Asian pear guide goes to 18 inches. Do the main cleanup in winter while the tree is dormant and the bacteria are inactive, but a strike racing down a branch in spring should come off as soon as you see it, and only cut in dry weather. Wipe the blades with a 1-to-9 bleach mix or rubbing alcohol between cuts, burn or bury what you remove, and if more than half the tree is blighted, Purdue says to take the tree out.Where you cut matters more than anything else: UC IPM's method is to find the lower edge of visible infection, trace the branch to its point of attachment and cut at the next branch juncture below, and both UC IPM and WSU report that cut placement matters more than tool sterilization, though dipping shears in 10 percent bleach between cuts is reasonable. The published distances run from Clemson's minimum of 8 to 12 inches through Purdue's at least 12 to WSU's 12 to 18 in wood two years old or older and Clemson's 18 inches for Asian pear, so 12 is a floor. Timing is dormant for the main removal, because growing-season pruning can spread the disease, with UC IPM's exception for rapidly advancing spring strikes on Asian pear, which come out at once; a trunk or scaffold canker can sometimes be saved by scraping bark to the cambium and taking 6 to 8 inches beyond any discolored streak, in winter. Do not shape the tree in the same pass, hold summer pruning until terminal buds have set, and keep nitrogen modest: UC IPM ties excess nitrogen and heavy pruning together as the two drivers of the succulent growth this bacterium needs.
Copper fungicide

Copper is a partial shield for the flowers, not a cure, and in UC IPM's California guidance it is the only fire blight material sold to home growers; Purdue and Clemson also describe streptomycin, an antibiotic sprayed during bloom, for home use where it can be found, and Purdue allows no more than three or four of those sprays a season. UC IPM's copper advice is a weak copper spray repeated every four to five days while the blossoms are open and the weather is warm and humid, starting once the day's average temperature tops 60°F; Clemson's simpler version is one copper spray right before bloom. It will not clear an infection already in the wood, and repeated copper can russet the fruit.Erwinia amylovora enters through open blossoms, so copper's job is to sit on the flower surface through the infection window UC IPM defines as rainy or humid weather with days of 75 to 85°F and nights above 55°F. UC IPM's program is a very weak (about 0.5 percent) Bordeaux or other copper as blossoms open once the 24-hour average temperature exceeds 60°F, at four-to-five-day intervals through late bloom, which on pear can mean five to twelve applications, and it says plainly this might reduce new infections but will not eliminate them or touch those already in wood. Copper accumulates in soil and can russet fruit, which is the case for Clemson's single pre-bloom spray on a tree not under heavy pressure. Streptomycin, the bloom antibiotic in the extension literature, is written for apple and capped by Purdue at three to four bloom sprays where it can be obtained at all. Do not irrigate during bloom.

No spray for this one. Prevention is the control.

Pear scab

D · 02

Symptoms Dark, fuzzy olive-to-black spots on the leaves, and rough, scabby, cracked patches on the pears. In a bad year the tree drops its leaves early. Asian pears get it less than European pears.Olive-green to black velvety spots on leaves, shoots, and fruit; fruit lesions crack, letting rot organisms in, and early-infected fruit ends up scabby and misshapen; severe infection yellows leaves and causes early defoliation. The pear analog of apple scab, and Asian pears are less susceptible to it than European pears. Cause A fungus that overwinters in last year's fallen leaves and spreads onto new leaves and fruit in cool, wet spring weather.Venturia pirina; the fungus overwinters primarily in fallen leaves, and in high-rainfall areas also in lesions on pear twigs, and infects during wet spring weather, most rapidly between 55 and 75°F with a minimum of 9 hours of continuous leaf wetness. Distinct from the apple-scab fungus but managed the same way. Organic treatment Sulfur spray in spring before the spots appear is the organic route. Once it is widespread it is too late for that year.Sulfur or a labeled fungicide on a protective spring schedule keyed to infection periods; prevention beats cure. Prevention The single best move is to rake up and remove fallen leaves every autumn, because that is where the fungus hides over winter; on one backyard tree that alone usually keeps scab at a level you can live with. Asian pears get it less than European pears, so most years need nothing more.Rake and remove fallen leaves each autumn or winter, which destroys the main overwintering source and on a single backyard tree can hold scab to tolerable levels; in high-rainfall areas the fungus also overwinters in twig lesions. Fungicide is needed only when rain keeps leaves wet 9 hours or more. Asian pears as a species are less susceptible than European pears, and a spray is only needed in a wet spring.

The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

Garden sanitation

Asian pears get scab less than European pears, UC IPM says so directly, and for a single backyard tree the whole program can be raking. The fungus spends the winter in last year's fallen leaves, so gather them up in autumn or winter and compost them thoroughly or get rid of them; UC IPM says that alone can hold scab to a level you can live with.Venturia pirina overwinters primarily in infected leaves on the ground, and UC IPM PN 7413 states that for a single backyard tree removing and composting or destroying the dropped leaves in autumn or winter can limit the disease to tolerable levels. In high-rainfall areas the fungus also carries over in lesions on pear twigs, which raking does not reach, and for several trees in a cool coastal climate PN 7413 adds urea on the foliage in autumn to hasten leaf fall (urea alone on pear, since zinc is phytotoxic to it), lime on the leaf piles, and running any sprinkler that wets foliage only between sunrise and noon so the leaves dry.
Sulfur

A spray is only worth it in a wet spring: UC IPM says fungicide is needed only when rain keeps the leaves wet for 9 hours or more. If that is your weather, sulfur goes on as the buds break, again 10 to 14 days later if it is still raining, and not past a month after petal fall. Never put sulfur on when it is near 90°F or hotter. And never mix it with oil or spray it close to an oil spray, because the pair burns leaves.Infection needs a minimum of 9 hours of continuous leaf wetness and runs fastest between 55 and 75°F, which is why PN 7413 makes fungicide conditional on rainy weather and puts the whole protective window between bud break and a month after petal fall, with a second application 10 to 14 days after the first if rain continues, once blossom clusters show but before they open. A protectant has no curative reach, so a spray after lesions appear is a season already lost; PN 7413 lists it for home use alongside fixed copper, Bordeaux, copper soap and neem or mineral oils. Sulfur and oil are never combined or applied close together. Sulfur is not applied near or above 90°F. On Asian pear, which PN 7413 rates less susceptible than European pear, most years will not meet the wet-weather trigger at all.

No spray for this one. Prevention is the control.

Pear decline

D · 03

Symptoms The tree slowly weakens over years, with small leaves that redden early in fall and a shrinking crop, or sometimes a sudden collapse. It is tied to the pear psylla insect and to certain rootstocks.Slow decline: the tree leafs out late in spring, leaves are small, thicken, curl downward and redden early, growth is weak and yield falls; or quick decline, where foliage wilts rapidly and the tree dies within days. A brown line of dead phloem at the graft union is the diagnostic mark. Driven by a phytoplasma transmitted by pear psylla and expressed through a sensitive rootstock. Cause A tiny disease organism carried by the pear psylla insect. How badly a tree is hit depends on its rootstock, so a resistant rootstock is the main protection.Candidatus Phytoplasma pyri, a phytoplasma (a bacteria-like organism) carried mainly by pear psylla, which injects it while feeding, and also passed on by grafting or budding with wood from an infected tree. It kills phloem cells at the graft union of sensitive root-scion combinations, so the roots starve; severity therefore depends on the rootstock, and pear on Asian pear roots (Pyrus pyrifolia, P. ussuriensis) can be killed rapidly while Old Home x Farmingdale and other tolerant roots hold up. Organic treatment There is no spray for it. Keep pear psylla under control, since that is the main way it spreads (grafting or budding wood from a sick tree can pass it on too), and, most importantly, start with a tolerant rootstock when you plant. A tree that collapses suddenly should be removed; one that is fading slowly can often be kept going with a little more fertilizer and frequent light watering.No spray or treatment for the tree itself is listed by UC IPM or Utah State, and UC IPM reports no known biological control of the phytoplasma; management is a tolerant rootstock chosen at planting (Old Home x Farmingdale, Bartlett seedling, Pyrus betulifolia, Winter Nelis), keeping pear psylla down to cut transmission, and vigor. Remove a tree in quick decline; a tree in slow decline may benefit from more nitrogen and frequent, light irrigation. Prevention Buy a tree grown on a rootstock that stands up to both decline and fire blight (the OHxF series, or birchleaf pear), never on Asian pear seedling roots, and keep pear psylla in check.Plant on a rootstock that tolerates decline and resists fire blight: OHxF 87, 97, 333 or 40, which WSU rates against both diseases, or Pyrus betulifolia. Bartlett seedling and Winter Nelis are also on UC IPM's decline-tolerant list, but Bartlett seedling is rated fire-blight susceptible on this crop's fire blight entry, so it is not the root to specify for an Asian pear. Keep psylla populations low. The sensitive roots are Asian pear seedlings themselves, Pyrus pyrifolia and P. ussuriensis, so an Asian pear on its own species' seedling is the worst case; and if top-working an Asian pear to a European cultivar, graft below the Asian pear's own union.

The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

Resistant rootstock

Pear decline is a disease of the graft union, so the roots your tree was grafted onto decide almost everything, and you choose them once, at the nursery. Ask for a tree on an Old Home x Farmingdale rootstock (OHxF 87, 97, 333 or 40), which WSU lists as resistant or tolerant to decline and to fire blight as well, or on birchleaf pear (Pyrus betulifolia), which UC IPM lists as decline-tolerant and which this crop's fire blight entry also recommends. Bartlett seedling is on UC IPM's tolerant list for decline, but it is rated fire-blight susceptible (see fire blight), and fire blight is the most serious disease of Asian pears, so it is not the root to ask for here. Avoid a tree on Asian pear seedling roots, because UC IPM says decline can rapidly kill a pear on Pyrus pyrifolia or Pyrus ussuriensis roots, and an Asian pear grown on its own kind of seedling is exactly that case. The other half of protection is keeping pear psylla down, since feeding psylla are the main way the disease moves from tree to tree; graft wood or buds taken from an infected pear can carry it too.Candidatus Phytoplasma pyri is injected by feeding pear psylla and kills phloem at the graft union of sensitive root-scion combinations, so sugar piles up above the union as starch while the roots starve; the brown line of dead phloem at the union is the field diagnostic, and quick decline is the tree collapsing within days once the union fails. Tolerance sits in the root: UC IPM lists Bartlett seedling, Old Home x Farmingdale, Pyrus betulaefolia and Winter Nelis seedling as tolerant and P. pyrifolia (P. serotina) and P. ussuriensis as the roots on which decline rapidly kills, and WSU's rootstock notes name OHxF 87 as tolerant to blight and decline and OHxF 97, 333 and 40 as resistant to it. One Asian-specific rule from Utah State: if you ever graft an Asian pear over to a European cultivar, graft below the union of the Asian pear and its rootstock, or you build a highly decline-susceptible tree. Reducing psylla abundance reduces transmission, which is why the psylla program on this crop is also the decline program.
Certified clean stock

Pear psylla are not the only way this disease gets into a tree: a bud or a piece of graft wood cut from an infected pear carries the disease with it, so a branch of another variety grafted onto your tree, or a new tree started from an old one, can bring decline in even where psylla are scarce. Take graft wood only from a pear that has never shown signs of decline, and where you have the choice, start with a nursery tree instead of wood from a pear whose history you do not know.Utah State's note on this disease adds grafting and budding to psylla as routes of transmission, which puts the source of scionwood and budwood on the same footing as the rootstock. Its field check is done with a knife on the donor tree: expose the cambium just under the bark at the graft union and look for a brown line, the dead phloem that UC IPM also describes at the union of an infected tree; wood from a tree that shows it is not used for propagation or top-working. Since no material listed by UC IPM or Utah State acts on the phytoplasma once it is in the tree, the choice is made once, when the wood is cut or the tree is bought.
Garden sanitation

A tree that collapses suddenly, wilting and dying within days, is not coming back and should be removed, both because UC IPM and Utah State list nothing that treats the disease inside it and because pear psylla can carry the infection from it to your other pears. A tree in slow decline is a different case: UC IPM says it may respond to more nitrogen and frequent light watering, so it can often be kept going for years.Utah State's management for decline is rootstock, psylla control and removal of diseased trees, and UC IPM's is the same plus vigor, with no material that acts on the phytoplasma and, in UC IPM's words, no known biological control of it. Removal is warranted for quick decline, where UC IPM describes hypersensitive tissue death at the graft union and collapse within days, and because the phytoplasma persists only in a pear tree or in the psylla, a dying tree is the local reservoir. Slow decline on a tolerant root is managed rather than removed: UC IPM notes such trees may benefit from increased nitrogen and frequent, light irrigation, and its commercial guideline attributes very slow decline to trees short of water and nutrition.

No spray for this one. Prevention is the control.

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Pear (Asian)

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Your pear (asian) year, month by month

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Pear (Asian)s need a partner

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The growing journey

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Yes, on a dwarf rootstock, 20 gallons and up

Soil pH for pear (asian)

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Feeding

Companion planting

When to pick

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