EPLP-019 11/19

Fasciation on Roses

Madalyn Shires, Graduate Extension Assistant, Department of and Microbiology Kevin Ong, Professor and Extension Plant Pathologist*

Fasciation, also known as cresting, is a rare phenom- The deformity is often localized to a single stem enon that occurs in more than 100 species of plants, (Fig. 3). Pruning the infected area usually stops the including roses. It commonly afflicts tobacco, which abnormal growth and it rarely occurs again, unless it makes it an economically important pathogen. This dis- is in the plant’s genes. Though symptoms tend to occur tortion, unusual and unpredictable, does no lasting harm only occasionally and in localized plant parts, some to the plant. Some plants are highly prized and bred for plants such as forsythia and Veronicastrum virginicum their unique fasciated characteristics. may repeatedly show fasciation year after year because of Symptoms Fasciation symptoms include flattened stems and shoots that seem to be made of several fused shoots (Fig. 1) as well as flattened, elongated, or misshapen flower heads (Fig. 2). Such characteristics appear in the stems, leaves, flowers, and of most plants.

Figure 1. Fasciation typically Figure 2. (Side view of Figure presents as flattened stems, 1 showing flattened stems, which often look like several canes, and leaves.) Leaves can stems fused together. camouflage the fasciation on Source: Katherine Olive plants. Source: Katherine Olive

Figure 3. Fasciation can also occur as a mass of stems that have grown together to create one large cane on the plant. Source: Paul * Texas A&M AgriLife Extension Service, The Texas A&M University System Winski, Texas A&M AgriLife Extension Service–Harris County

1 a genetic predisposition. Since abnormalities in actively plants. Always use good hygiene when pruning plants growing tissues cause the deformities, symptoms are with fasciation symptoms. Though it is not contagious, most prevalent during spring and summer. the causal agents might be and can be controlled using respective measures (for example, fungicides for fungal Causes agents). If symptoms are present, prune out affected Though caused by many factors, fasciation symptoms plant parts and dispose of them properly by burning are usually triggered by an abnormal hormonal change in plant material or placing pruned material in with the apical , or growing tip, of the plant. During non-plant-material trash. Do not compost with it because active growth, the apical meristem typically concentrates if a pathogen caused the symptoms, it could infect other around a single point to produce cylindrical tissue. But, plants through compost application. during fasciation, the growing tip elongates perpen- dicularly to the direction of growth, creating flattened, References distorted tissue. Fasciation. Royal Horticultural Society. https://www.rhs. Other causes may be a bacterial, viral, or fungal infec- org.uk/advice/profile?pid=525 tion, random genetic mutation, frost damage, animals Klingaman, Gerald. 2008. Plant of the Week: Fasciated and insects, and chemical or mechanical injury from cul- Plants (Crested Plants). The University of Arkansas tural practices. The phytopathogenic bacterium, Rhodo- Division of Agriculture. https://www.uaex.edu/yard- coccus fascians, produces fasciated symptoms in a wide garden/resource-library/plant-week/fasciated-2-22-08. range of hosts. Fasciation can also appear in conjunction aspx with Rose rosette , mainly because of the lowered defense system of the infected roses. For more information, contact the Texas Plant Dis- ease Diagnostic Lab at [email protected] or Kevin Management Ong at [email protected]. There are not many control measures associated with fasciation. Various factors cause the condition, it does Acknowledgment no lasting harm to the plant, and is usually localized and Katherine Olive, Undergraduate Extension Assistant, temporary. Prevention entails avoiding injury to plant contributed to the manuscript of this publication. bases, avoiding overwatering, and not grafting fasciated

Extension Plant Pathology http://plantclinic.tamu.edu

The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Texas A&M AgriLIfe Extension Service is implied. Because the status of pesticide label clearance is subject to change, the user is responsible for checking product labels for proper and legal usage and rates.

Texas A&M AgriLife Extension Service AgriLifeExtension.tamu.edu More Extension publications can be found at AgriLifeBookstore.org Texas A&M AgriLife does not discriminate on the basis of race, color, religion, sex, national origin, disability, age, genetic information, veteran status, sexual orientation, or gender identity and provides equal access in its programs, activities, education, and employment. The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating. New

2