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Crown Gall

Crown Gall

Agrobacterium tumefaciens

Bacterialalso: Crown gall

A bacterial disease that causes rough, tumor-like galls on the roots, crown, and lower stems of a huge range of plants, from fruit trees and brambles to roses and grapes. The galls disrupt the flow of water and nutrients, stunting and weakening the plant, and the bacteria can persist in the soil for years once established.

🔎 How to spot it

Look for rounded, rough, tumor-like growths, at first soft, spongy, and cream-colored, later hard, woody, and dark, on the roots, the crown at the soil line, and the lower stems or trunk. Galls range from pea-sized to several inches across. Above ground the plant may be stunted, weak, and slow, with poor vigor, especially when young.

🥀 Damage it causes

The galls disrupt the movement of water and nutrients through the affected tissue, so plants are stunted, weak, and less productive, and young or nursery plants can be seriously set back or killed. Older plants often survive but decline, and the wounds and galls open the way to secondary wood rots.

🔬 What causes it

Crown gall is caused by the soil bacterium Agrobacterium tumefaciens, which enters only through wounds, from pruning, transplanting, cultivation, grafting, or insects, near the soil line. The bacteria insert genes that make the plant tissue grow the gall. They survive in galls and in the soil for years, and spread on infected nursery stock, tools, and soil water.

🛡️ Prevent it

Start with clean, gall-free nursery stock and inspect roots and crowns before planting, rejecting any with galls. Avoid wounding the crown and roots when planting and cultivating, and disinfect pruning and grafting tools. Do not replant susceptible plants into known infested ground. A preventive root dip with the biological agent Agrobacterium radiobacter K-84 protects new plantings at planting time.

🧯 If it is already here

There is no cure once a plant is galled, so dig out and destroy severely affected young plants, and do not replant susceptible species in that spot. An established tree with a few galls may live for years, so keep it vigorous and watch for secondary rots. Because the bacteria persist in the soil, prevention and sanitation, not treatment, are the real controls.

💡 Good to know

Crown gall has an enormous host range, which is why it turns up on everything from roses and brambles to fruit and nut trees. The soft, tumor-like galls at the crown distinguish it from the firmer, woody burls some plants form naturally. Because it enters through wounds and lingers in soil, gentle handling at planting and clean stock prevent most cases.

🌱 Plants it affects

157 plants in the library can be affected by this problem

🍓Albion StrawberryAlice du Pont MandevillaAmerican BasswoodAmethyst Falls WisteriaAmish Paste TomatoAnjou PearAnnabelle Smooth HydrangeaApril Tryst CamelliaAroniaAsian PearAugust Beauty GardeniaAunt Molly's Ground CherryBachelor's ButtonBalsam PoplarBarbara Karst BougainvilleaBartlett PearBeach Plum🍅Beefmaster TomatoBetter Boy Tomato🍅Big Beef TomatoBig Boy TomatoBilberryBing CherryBlack Cherry TomatoBlack CrowberryBlack CurrantBlack Krim TomatoBlack RaspberryBlack Tartarian CherryBlack WalnutBlue Bird Rose of SharonBluecrop BlueberryBosc Pear🍅Box Car Willie TomatoBoysenberryBraeburn AppleBrandywine TomatoBurning BushCatawba GrapeCelebrity TomatoChampagne LoquatCherokee Purple TomatoChokecherryClimbing HydrangeaClimbing Prairie RoseConcord GrapeContender PeachCoral Drift Groundcover RoseCornelian CherryCortland AppleCosmic Crisp AppleCranberryDamson PlumDiabolo NinebarkEarly Amethyst BeautyberryEarly Girl TomatoElberta PeachElderberryEndless Summer HydrangeaEnglish WalnutEvergreen HuckleberryFantasia NectarineFlowering DogwoodFuji AppleGala Apple🍅German Queen TomatoGoji BerryGoldflame SpireaGooseberryGraham Thomas English RoseGranny Smith AppleGreen Zebra TomatoHansa Rugosa RoseHawthornHeritage RaspberryHoneoye StrawberryHoney LocustHoneyberryHoneycrisp AppleHummingbird SummersweetIceberg Floribunda RoseIndian HawthornIndigo Rose TomatoJackmanii ClematisJuliet Grape TomatoJune-Bearing StrawberryKaren AzaleaKellogg's Breakfast TomatoKnock Out Rose🍅La Roma IV TomatoLemon Boy TomatoLimelight Panicle HydrangeaLynwood Gold ForsythiaMajor Wheeler Trumpet HoneysuckleMammoth SunflowerMcIntosh AppleMethley PlumMiss Kim LilacMiss Molly Butterfly BushMister Lincoln Hybrid Tea Rose

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.