Rose

Rosa spp.

Black Spot

Fungal pathogen

Marssonina rosae( sexual stage, Diplocarpon rosae)

Area(s) affected

Leaves

Signs/Symptoms

Round to irregularly shaped, light brown to black spots form on the leaf surface. Infected leaves soon turn yellow and drop from the plant. This results in plant death. Spots can occur on petioles, twigs and canes as well.

Photo credit: John Hartman, University of Kentucky, Bugwood.org

Photo credit: John Hartman, University of Kentucky, Bugwood.org

For more information

https://www.extension.purdue.edu/extmedia/BP/BP-139-W.pdf

 

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Cankers (Brand, Common, & Brown)

Fungal pathogen(s)

Coniothyrium spp. & Cryptosporella umbrina (asexual stage, Phomopsis umbrina)

Area(s) affected

Canes

Signs/Symptoms

Fungus will form light brown to black, sunken or cracked lesions on the cane. Living tissue may surround the lesion and the lesion might girdle the cane killing all parts above it.

Photo credit: Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org

Photo credit: Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org

For more information

https://pnwhandbooks.org/plantdisease/host-disease/rose-rosa-spp-hybrids-brand-common-canker

 

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Cotton Root Rot

Fungal pathogen

Phymatotrichopsis omnivora (previously Phymatotrichum omnivorum)

Area(s) affected

Roots

Signs/Symptoms

Infected plants die suddenly. Root bark is decayed and brownish, and bronze colored wooly strands of the fungus are frequently apparent on the root surface. Leaves will turn brown and remain attached to the shrub.

For more information

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2321/EPP-7621web.pdf

 

 

Cylindrocladium Leaf and Stem Rot

Fungal pathogen

Cylindrocladium scoparium

Area(s) affected

Leaves and stem

Signs/Symptoms

Mainly a problem of greenhouse propagated roses. Cankers develop at the base of the affected stem. There is a distinct transition from the healthy part of the stem (green) to the diseased part of the stem (black). Will cause the plant to wilt suddenly.

For more information

http://www.freshfromflorida.com/content/download/11371/144522/pp364.pdf

 

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Crown Gall

Bacterial pathogen

Agrobacterium tumefaciens

Area(s) affected

Crown

Signs/Symptoms

Woody galls form on lower stems and root tissue. If the gall girdles the lower stem or main roots, the plant may be killed.

Photo credit: Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Photo credit: Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

For more information

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Downy Mildew

Fungal pathogen

Peronospora sparsa

Area(s) affected

Leaves

Signs/Symptoms

This disease causes severe and rapid defoliation. The fungus is active only under cool, damp conditions. Leaf symptoms vary from angular blotches (yellow, purple to brown), to a scorch like burn. Under conditions of high humidity, a purplish-gray mass develops on the undersurfaces of the infected leaves.

Photo credit: Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Photo credit: Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Photo credit: Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Photo credit: Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

For more information

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Mosaic Virus

Causal agent

Apple mosaic virus and Prunus necrotic ringspot virus

Area(s) affected

Leaves

Signs/Symptoms

Variable yellow and green patterns occur on leaves. This can be in the form of yellow bands or ringspots, wavy lines, yellow vein banding, or splotches of yellow and green.

Photo credit: William M. Brown Jr., Bugwood.org

Photo credit: William M. Brown Jr., Bugwood.org

Photo credit: Lesley Ingram, Bugwood.org

Photo credit: Lesley Ingram, Bugwood.org

For more information

http://aces.nmsu.edu/ces/plantclinic/documents/rose-mosaic-virus-_od-9__final.pdf

 

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Powdery Mildew

Fungal pathogen

Podosphaera (previously Sphaerotheca) pannosa var. rosae

Area(s) affected

Leaves, shoots, and flower buds

Signs/Symptoms

A white powdery growth develops on leaves, buds and twigs causing them to be distorted and dwarfed. Growth is most often seen on the upper leaf surface, but can also be seen on the lower leaf surface. Young, tender growth is most susceptible.

Photo credit: Powdery mildew_Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Photo credit: Powdery mildew_Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org

For more information

http://apps.rhs.org.uk/advicesearch/profile.aspx?PID=748

 

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Root Knot Nematode

Pathogen

Meloidogyne hapla

Area(s) affected

Roots

Signs/Symptoms

Feed on the inside of the roots inducing knots or galls on them. These swellings are usually white and round to irregularly elongated. Foliage may wilt, appear stunted, and turn yellow to bronze.

Photo credit: Gerald Holmes, Valent USA Corporation, Bugwood.org

Photo credit: Gerald Holmes, Valent USA Corporation, Bugwood.org

For more information

http://www.apsnet.org/edcenter/intropp/lessons/Nematodes/Pages/RootknotNematode.aspx

 

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Rose Rosette

Causal agent

Rose Rosette Virus

Area(s) affected

Entire plant

Signs/Symptoms

The virus is transmitted by eriophyid mites. Symptoms include distorted, small leaves, short internodes, red pigmentation of foliage, excessive thorniness and proliferation of shoots (witches broom). Infected plants generally die within one year.

Photo credit: Ashley Brake, Texas A&M University

Photo credit: Ashley Brake, Texas A&M University

Photo credit: Ashley Brake, Texas A&M University

Photo credit: Ashley Brake, Texas A&M University

Photo credit: Ashley Brake, Texas A&M University

Photo credit: Ashley Brake, Texas A&M University

For more information

http://www2.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-OR-W-16.pdf

http://pubs.ext.vt.edu/450/450-620/450-620_pdf.pdf

 

Rust

Fungal pathogen

Phragmidium mucronatum

Area(s) affected

Leaves

Signs/Symptoms

Rust is a rare problem but can cause serious defoliation. Small, raised, orange pustules occur on the lower leaf surface. Corresponding yellow spots occur on the upper surface. Depending on the spore stage, rust pustules can be orange, red or black.

Photo credit: Gerald Holmes, Valent USA Corporation, Bugwood.org

Photo credit: Gerald Holmes, Valent USA Corporation, Bugwood.org

Photo credit: Gerald Holmes, Valent USA Corporation, Bugwood.org

Photo credit: Gerald Holmes, Valent USA Corporation, Bugwood.org

Photo credit: Lelsey Ingram, Bugwood.org

Photo credit: Lelsey Ingram, Bugwood.org

For more information

Jones, Ronald K., and D. M. Benson. “Chapter 76: Rose Diseases.” Diseases of Woody Ornamentals and Trees in Nurseries. St. Paul, MN: APS, 2001. N. pag. Print.

 

Spring Dwarf

Causal agent

Unknown

Area(s) affected

Leaves

Signs/Symptoms

Symptoms are noticed when leaves first emerge in the spring. Shortened internodes give a balled appearance. Leaves are short and curved.

For more information

http://web.aces.uiuc.edu/vista/pdf_pubs/632.pdf

 

 

Verticillium Wilt

Fungal pathogen

Verticillium spp.

Area(s) affected

Entire plant

Signs/Symptoms

Foliage will suddenly wilt and appear scorched or a single branch will defoliate. Vascular discoloration can be seen when a cross-section is taken of an infected branch. Colors range from brown to gray to green. Infected root tissue may also have discoloration.

For more information

http://www.ipm.ucdavis.edu/PMG/r280100911.html

 

 

 

For additional support and current disease management information, contact your local AgriLife Extension Office: http://counties.agrilife.org/

Content editor: Corinne Rhodes, Undergraduate Extension Assistant, Texas Plant Disease Diagnostic Laboratory.  This project was performed to satisfy BESC485 requirement under the supervision of Dr. Kevin Ong,  kevo@tamu.edu, Director, Texas Plant Disease Diagnostic Laboratory, Texas A&M University, Texas AgriLife Extension Service (April 25, 2014)

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