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Fire Blight

Fire Blight

Erwinia amylovora

Bacterialalso: Blight

A destructive bacterial disease of apple, pear, and their rose-family relatives that makes shoots look scorched, as if burned. Fire blight can kill blossoms, shoots, and whole limbs in a single season and, in a bad year, take down a young tree. It spreads fast in warm, wet spring weather, and prompt pruning is the main defense.

🔎 How to spot it

Look for blossoms and shoots that suddenly wilt, turn brown to black, and die, with the dead leaves clinging to the branch rather than dropping. Infected shoot tips bend over into a distinctive shepherds-crook shape. Branches and the trunk develop dark, sunken, slightly cracked cankers, which may ooze a sticky amber bacterial liquid in warm, humid weather.

🥀 Damage it causes

Fire blight kills flowers, shoots, and branches, and the infection can run down a limb into the trunk and girdle and kill the whole tree, especially young or vigorously growing ones. Beyond the immediate dieback, the cankers it leaves behind carry the bacteria into the next year.

🔬 What causes it

Fire blight is caused by the bacterium Erwinia amylovora, which attacks apple, pear, quince, crabapple, hawthorn, serviceberry, and other rose-family plants. It overwinters in cankers on the tree and, in spring, oozes bacteria that insects, rain, and wind carry to open blossoms and tender shoots. Warm, humid weather during bloom, succulent fast growth, and wounds all favor it.

🛡️ Prevent it

Plant resistant apple and pear varieties and avoid the most susceptible ornamentals. Keep trees in moderate vigor by going easy on nitrogen and on heavy pruning, since lush, fast growth is highly susceptible. Avoid overhead watering. Watch closely during warm, wet bloom periods, and disinfect pruning tools between cuts so you do not spread the bacteria.

🧯 If it is already here

There is no cure, so prune out blighted wood promptly: cut 8 to 12 inches below the visible edge of the infection, ideally in dry weather, and disinfect tools between every cut. Remove and destroy the prunings. Protective blossom sprays of copper or a labeled biological can reduce new infections during bloom, but cutting out strikes quickly is the core of control.

💡 Good to know

The scorched look and the hooked, dying shoot tips are the classic tells of fire blight. Because the bacteria overwinter in cankers, careful dormant-season removal of every blighted branch is what keeps it from exploding again in spring. Pruning during dry weather and sterilizing tools between cuts are essential so you do not spread it as you work.

🌱 Plants it affects

68 plants in the library can be affected by this problem

Adirondack Blue Potato🥔All Blue PotatoAmish Paste TomatoAnjou PearAnnual VincaApril Tryst CamelliaAroniaAsian PearBartlett Pear🍅Beefmaster TomatoBetter Boy Tomato🍅Big Beef TomatoBig Boy TomatoBlack Kabouli ChickpeaBlack Krim TomatoBosc Pear🍅Box Car Willie TomatoBoxwoodBraeburn AppleBrandywine TomatoBurning BushCalifornia Giant ZinniaCelebrity TomatoChampagne LoquatCherokee Purple TomatoChinese ChestnutCortland AppleCosmic Crisp AppleCosmic Purple CarrotCranberry CotoneasterCreeping PhloxCuminEarly Girl TomatoFingerling PotatoFuji AppleGala AppleGerman Butterball PotatoGranny Smith AppleHawthornHazelnutHoneycrisp AppleIndian HawthornKaren AzaleaKellogg's Breakfast TomatoKennebec Potato🍅La Roma IV TomatoLemon Boy TomatoMcIntosh AppleMulberryNorland PotatoPineapple TomatoPink Lady ApplePistachioPrickly Pear🥔Purple Majesty PotatoQuinceRed Delicious AppleRed Pontiac PotatoRegent SaskatoonRoma TomatoRusset Potato🍅Rutgers TomatoSan Marzano TomatoSarah Bernhardt Peony🍅Striped German TomatoSugar AppleTaroTexas Scarlet Flowering Quince

For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.