Crown Gall
Crown Gall
Crown gall is caused by a bacterium, Agrobacterium tumefaciens, and affects apples, pears, quince, peaches, nectarines, apricots, plums, and cherries. The disease is common in tree fruit nurseries and can occur in orchards.
Symptoms Crown gall is readily recognized by wartlike swellings, or galls, on tree roots and crown. Occasionally, the galls may be seen aboveground on trunks or branches. Young galls are light in color and with age become dark and hard, ½ inch to 3 or 4 inches in diameter. When galls are numerous, or if located on major roots or the crown, they may disrupt the flow of water and nutrients. Trees show reduced growth, an unhealthy appearance, and possibly nutritional deficiency symptoms.
Disease cycle The bacteria causing crown gall are distributed widely in numerous soils and can attack many different kinds of plants. Soil may become contaminated if planted with infected nursery stock. Bacteria entering the plant must do so through a wound. Wounds are commonly made during digging and tree-planting operations, by tillage equipment, and by injury from root-feeding insects and nematodes. Secondary galls may develop a considerable distance from the initial infection. These may be formed in the absence of the crown gall bacteria, apparently due to a tumor-inducing substance produced at the site of the original infection.
Disease management Avoid planting infected stock or wounding trees at planting.
Contact Information
Young galls are light in color and with age become dark and hard, ½ inch to 3 or 4 inches in diameter. Photo by B. Butler.
Kari A. Peter Assistant Professor [email protected] 717-677-6116
Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture. Where trade names appear, no discrimination is intended, and no endorsement by Penn State Extension is implied. This publication is available in alternative media on request.
Penn State is an equal opportunity, affirmative action employer, and is committed to providing employment opportunities to all qualified applicants without regard to race, color, religion, age, sex, sexual orientation, gender identity, national origin, disability or protected veteran status. © The Pennsylvania State University 2017
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Crown Gall
Crown gall is caused by a bacterium, Agrobacterium tumefaciens, and affects apples, pears, quince, peaches, nectarines, apricots, plums, and cherries. The disease is common in tree fruit nurseries and can occur in orchards.
Symptoms Crown gall is readily recognized by wartlike swellings, or galls, on tree roots and crown. Occasionally, the galls may be seen aboveground on trunks or branches. Young galls are light in color and with age become dark and hard, ½ inch to 3 or 4 inches in diameter. When galls are numerous, or if located on major roots or the crown, they may disrupt the flow of water and nutrients. Trees show reduced growth, an unhealthy appearance, and possibly nutritional deficiency symptoms.
Disease cycle The bacteria causing crown gall are distributed widely in numerous soils and can attack many different kinds of plants. Soil may become contaminated if planted with infected nursery stock. Bacteria entering the plant must do so through a wound. Wounds are commonly made during digging and tree-planting operations, by tillage equipment, and by injury from root-feeding insects and nematodes. Secondary galls may develop a considerable distance from the initial infection. These may be formed in the absence of the crown gall bacteria, apparently due to a tumor-inducing substance produced at the site of the original infection.
Disease management Avoid planting infected stock or wounding trees at planting.
Contact Information
Young galls are light in color and with age become dark and hard, ½ inch to 3 or 4 inches in diameter. Photo by B. Butler.
Kari A. Peter Assistant Professor [email protected] 717-677-6116
Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture. Where trade names appear, no discrimination is intended, and no endorsement by Penn State Extension is implied. This publication is available in alternative media on request.
Penn State is an equal opportunity, affirmative action employer, and is committed to providing employment opportunities to all qualified applicants without regard to race, color, religion, age, sex, sexual orientation, gender identity, national origin, disability or protected veteran status. © The Pennsylvania State University 2017
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Crown Gall
