Boxwood

Buxus spp.

Phytopthora Root and Crown Rot

Fungal pathogen

Phytophthora cinnamomi and Phytophthora parasitica

Area(s) affected

Roots and crown

Signs/Symptoms

Foliage will have an off-color, appearing tan and dried- out. As the disease progresses, individual sections of the canopy will brown. Roots turn dark brown and lower stem and crown tissue turn dull gray to brown.  If root and crown rot are severe, plant death will occur.

For more information

 

 

 

Root Knot Nematode

Pathogen

Meloidogyne spp.

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.

For more information

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

 

 

 

Ectoparsitic Nematodes

Pathogen

Ring, Stubby Root, and  Stunt

Area(s) affected

Roots

Signs/Symptoms

Feed on root tips causing foliage to wilt, appear stunted and turn yellow to bronze.

For more information

http://plantpath.caes.uga.edu/extension/nematodes/ring.html

http://plantpath.caes.uga.edu/extension/nematodes/stubbyroot.html

 

 

Lesion Nematode

Pathogen

Pratylenchus spp.

Area(s) affected

Roots

Signs/Symptoms

Feed on both the outside and inside of roots causing darkened areas of dead tissue along the root as they move and feed. Foliage may wilt, appear stunted, and turn orange or bronze.

For more information

https://www.apsnet.org/edcenter/intropp/lessons/Nematodes/Pages/LesionNematode.aspx

 

 

Decline, Dieback, Root Rots, Twig Blight, Cankers

Fungal pathogens

Armillaria spp., Fusarium spp., Gandoderma spp., Nectria spp., Phymatotrichum spp., Rhizoctonia spp.

Area(s) affected

 

Signs/Symptoms

Infected branches often start growth later in spring than normal ones. Leaves on such branches usually curl upward close to the stem and turn light grayish-green or bronze and finally straw-colored. Leaves may wither and drop early leaving bare twigs. Roots may be decayed. The bark at base of branches may die and slough off.

For more information

 

 

 

Leaf Spots, Leaf Tip Blights, Leaf Cast

Fungal pathogen

Diplodia spp., Phoma spp., Phyllosticta spp.

Area(s) affected

Leaves

Signs/Symptoms

Leaves variously spotted may become pale or straw-colored, sometimes dull tan or brown, starting at margins and tips. Many leaves drop early. Young twigs may die.

For more information

 

 

 

Winter Injury

Causal agent

Freezing temperatures

Area(s) affected

Entire plant

Signs/Symptoms

Leaves may turn bronze, rusty brown or red with dead areas around the margins. Leaves, twigs and even entire plants may die back.

For more information

http://www.mobot.org/gardeninghelp/plantfinder/hortline.asp?code=3959

 

 

 

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)

Print Friendly

Comments are closed.