Fire Blight on Pear Trees: Symptoms, Treatment and Prevention

By the Garden Voila editorial team · Updated October 30, 2026 · How we verify

Fire blight is a destructive bacterial disease of pear trees, caused by Erwinia amylovora, that makes blossoms, shoots and branches turn black and wilt as if scorched by fire, with shoot tips bending into a “shepherd’s crook”. It spreads in warm, wet weather during bloom, carried by rain and insects, including bees. There is no cure, but you can limit it by pruning out infected branches 8 to 12 inches below visible damage in dry dormant weather, disinfecting tools between cuts, avoiding excess nitrogen and heavy pruning, planting resistant pear varieties and, where needed, using bloom-time protective sprays exactly as the label directs.

Fire blight fact sheet

What does fire blight look like on a pear tree?

The Clemson Cooperative Extension fire blight fact sheet describes the main symptoms:

• Blossom blight: In spring, flower clusters wilt, turn brown to black and die, often soon after bloom.
• Shoot blight: Young shoots wilt from the tip, turn black and bend over into a shepherd’s crook. Pear shoots and leaves turn especially black.
• Scorched leaves: Infected leaves blacken but stay attached to the branch, giving the tree a burned look.
• Cankers: Sunken, dark, sometimes cracked areas on branches and the trunk, where the bacteria survive the winter.
• Ooze: In warm, wet weather, infected parts and cankers ooze sticky, milky to amber droplets full of bacteria.
• Fruit: Young fruit can shrivel, blacken and hang on the tree like mummies.

What causes fire blight?

Fire blight is caused by the bacterium Erwinia amylovora, native to North America. The bacteria overwinter at the edges of cankers on infected branches. In spring, when temperatures rise above about 60°F and the weather is rainy or humid, they multiply and ooze out of the cankers. Clemson notes that rain splash and insects, including bees, ants, flies, aphids and beetles attracted to the ooze, carry bacteria to open blossoms, where they infect the flowers and move into the shoots. Bacteria also enter through fresh wounds from hail, pruning and insect feeding and through natural openings. Young, fast-growing, succulent shoots are the most vulnerable.

Why are pears so susceptible to fire blight?

Most European pear varieties, including Bartlett, Bosc and many old favorites, are highly susceptible, and the disease moves rapidly through their tissues. Pears also bloom early and sometimes produce late “rat-tail” blossoms after the main bloom, giving the bacteria extra opportunities. Clemson notes that pear is particularly susceptible, and that callery pears such as ‘Bradford’, planted widely as ornamentals, can harbor the disease and serve as a source of infection for nearby fruit trees.

How do you treat fire blight on a pear tree?

There is no cure for infected wood, but you can stop it spreading and protect new growth.

1. Prune in dormancy. Clemson recommends removing blackened twigs and cankers during the dormant season, when the bacteria are inactive, and warns that growing-season pruning can spread the disease.
2. Cut well below the damage. Make each cut at least 8 to 12 inches below any visible sign of infection, into healthy wood, because bacteria move ahead of the visible symptoms.
3. Disinfect tools. Dip or wipe pruners between every cut with 70 percent alcohol or a 10 percent bleach solution (1 part bleach to 9 parts water). Oil tools afterward if you use bleach, which corrodes metal.
4. Destroy prunings. Remove infected wood from the site promptly and burn, bury or bag it.
5. Remove suckers and water sprouts. These soft shoots are highly susceptible.
6. Remove severe cankers or trees. If the trunk or main scaffold is heavily infected, removing the tree may protect others nearby.

If you must remove fresh strikes in summer, many extension services suggest cutting during dry weather and leaving a short stub, then making a proper cut back to a branch in winter. Our guide to loppers covers tool cleaning.

How do you prevent fire blight on pears?

Plant resistant varieties

Resistance is the most effective defense. Clemson lists edible pears with some resistance, including Ayers, Kieffer, LeConte, Moonglow, Magness, Orient and Seckel (somewhat resistant), and Asian pears such as Chojuro, Hosui (somewhat resistant), Seuri and Shinko. Other varieties often noted for good resistance include Harrow Delight, Potomac and Warren. Highly susceptible varieties include Bartlett, Bosc and Clapp’s Favorite. No pear is immune, but resistant varieties suffer far less.

Keep growth moderate

Clemson advises avoiding excess nitrogen, which produces succulent growth that infects easily. Feed pears only when needed, avoid lawn fertilizers near trees and prune lightly, because heavy pruning stimulates vigorous, susceptible shoots. The University of Illinois Extension also advises keeping the growth rate low in bearing pear trees.

Remove sources of infection

Prune out cankers every winter, remove wild or neglected pears, apples, hawthorns and ornamental callery pears nearby if practical, and remove late blossoms that appear after the main bloom.

Protect blossoms

Clemson lists two types of protective sprays for home trees: a copper product applied before bloom to reduce bacteria on bark surfaces, and streptomycin applied at bloom every 3 to 4 days while flowers are open, starting when flowers open and at least 50 days before harvest. Sprays reduce severity but are not 100 percent effective, and full coverage of large trees is difficult. Copper can russet fruit and leaves if applied at the wrong stage.

Which pear varieties resist fire blight?

Resistance lists follow Clemson’s fact sheet and common extension recommendations; local performance varies. See our guide to types of pears for flavor and use.

When is fire blight most active?

Infection risk is highest during bloom and shortly after, when warm temperatures (above about 60°F and especially 65 to 85°F) coincide with rain, heavy dew or high humidity. Hail storms and strong winds that wound leaves and shoots can trigger infections later in the season. Shoot blight can continue through early summer while shoots are growing actively. In hot, dry midsummer weather, the disease usually slows. Commercial growers use weather-based models to predict infection risk and time sprays.

Can a pear tree recover from fire blight?

Often, yes, if infections are limited to blossoms and young shoots and you prune them out promptly in dormancy. Trees with cankers on the main trunk or many large limbs may decline or die, especially young trees and very susceptible varieties. Recovery is faster when you keep growth moderate, prune out infections each winter and protect blossoms in high-risk years.

Does fire blight affect apples and other trees?

Yes. Apples, crabapples, quince and many ornamental shrubs in the rose family are hosts. Fire blight on apples looks the same, with blackened blossoms and shepherd’s-crook shoots. Resistant apples include Liberty, Enterprise, Freedom and Gold Rush; see our guides to the Liberty apple and crabapple tree. Dwarfing apple rootstocks such as M.9 and M.26 are susceptible, while Geneva rootstocks were bred for resistance.

Fire blight vs other pear problems

Use the plant problem identifier if you are unsure.

Where did fire blight come from?

Fire blight is native to North America and was first described in the Hudson Valley of New York in the late 1700s, when it devastated early pear orchards. It was one of the first plant diseases shown to be caused by a bacterium, in the late 1800s. It has since spread to Europe, the Middle East, New Zealand and other regions, where it is a regulated pest in some countries. The Wikipedia article on fire blight summarizes its history and spread.

How do you prune pear trees to reduce fire blight?

Pruning style matters as much as removing infections. Prune pears lightly, because heavy cuts stimulate vigorous, susceptible shoots. The University of Illinois Extension advises pruning pears less severely than apples and keeping growth modest. Remove water sprouts and root suckers, open the canopy so leaves dry quickly after rain, and avoid large heading cuts. Do structural pruning in late winter, never in wet spring weather. Our full guide on how to prune a pear tree explains training and annual pruning.

Fire blight prevention calendar for pear trees

Should you remove a pear tree with fire blight?

Not usually, if the infection is confined to twigs and smaller branches. Consider removal if the main trunk has a large canker, if most scaffold limbs are infected, or if a highly susceptible tree reinfects every year and threatens nearby fruit trees. Replacing it with a resistant variety such as Moonglow or Magness often solves the problem permanently. If you remove a tree, also remove the stump or kill root suckers, which are very susceptible.

With resistant varieties, light pruning, moderate feeding and prompt removal of infections each winter, most home pear trees live with fire blight and still produce good crops year after year.

If fire blight keeps returning despite good care, ask your local extension office to confirm the diagnosis and recommend the most resistant varieties for your area.

Planning more fruit? Browse every variety, planting and care article in our complete fruit tree growing guide.

How fire blight spreads and what to prune

University of Illinois Extension’s managing fire blight in apples and pears at home lists the symptoms: water-soaked then brown blossoms, shoots that turn brown to black with tips curling into a shepherd’s crook while leaves stay attached through summer, fruit that turns brown to black with whitish-tan ooze, and sunken cankers that can girdle branches. Bacteria overwinter at canker margins and multiply when spring turns warm (around 65°F, 18°C) and wet. Flies and bees that feed on ooze carry bacteria to flowers, the most common entry route, and wounds from pruning, wind or hail also allow infection. Young succulent shoots are most susceptible, so heavy pruning or nitrogen fertiliser raises the risk.

• Prune dormant trees when possible, cutting at least 6 to 8 inches below cankers. In the growing season, prune in dry conditions, cut 6 to 12 inches below visible symptoms, sanitise pruners between cuts and destroy infected material.
• Resistant varieties: apples such as Gold Rush, Empire, Enterprise, Liberty and Winecrisp; pears such as Magness, Maxine, Moonglow and Summercrisp. Not immune, but less affected.
• Avoid overfertilising and excess summer pruning, which trigger susceptible flushes.
• Sprays: copper in dormancy and at green tip reduces bacterial build-up; streptomycin during bloom protects flowers but cannot cure disease, with no more than three or four applications a season. Fungicides do not control fire blight because it is bacterial.
• An infected Callery pear can be cut at ground level and replaced.

Frequently asked questions

Fact-checked against: Clemson Cooperative Extension, Fire Blight of Fruit Trees; University of Illinois Extension, Pears; US EPA, Pesticide Labels.

Reviewed October 2026. Sources: University of Illinois Extension, Managing fire blight in apples and pears at home