Boxwood Dieback: Colletotrichum theobromicola

Figure 1JPG

Figure 1. This random dieback of twigs with light tan-colored foliage is caused by boxwood dieback.

Figure 2JPG

Figure 2. The roots and crowns of boxwood plants infected by Colletotrichum theobromicola appear healthy.

Figure 11JPG

Figure 3. A Baby Gem boxwood (Buxus microphylla) infected with boxwood dieback caused by Colletotrichum theobromicola </i>exhibits early symptoms of light green foliage in the middle of the canopy.

Figure 7jpg

Figure 4. Acervuli (fruiting bodies, at yellow arrows) of Colletotrichum theobromicola erupting through the epidermis of an infected boxwood stem.

Figure 4JPG

Figure 5. This bright black discoloration of the upper part of the boxwood stem under the bark is caused by Colletotrichum theobromicola.

Figure 5JPG

Figure 6. This bright black discoloration of the lower part of the boxwood stem under the bark is caused by Colletotrichum theobromicola.

Figure 8jpg

Figure 7. Bright-black discoloration under the bark of the same boxwood stem as shown in Figure 4 caused by Colletotrichum theobromicola.

Figure 6JPG

Figure 8. A cross section of a symptomatic boxwood twig infected with boxwood dieback shows discoloration extending to the center of the woody tissue.

Figure 9jpg

Figure 9. This boxwood leaf lesion is caused by Colletotrichum theobromicola.

Figure 10JPG

Figure 10. These are foliar symptoms of boxwood plants infected with Phytophthora root rot.

Figure 13jpg

Figure 11. Boxwood blight is caused by Calonectria pseudonaviculata. Photo by V. L. Smith, Connecticut Agricultural Experiment Station.

Figure 12jpg

Figure 12. This boxwood is infected with Macrophoma blight.

Figure 11JPG

Figure 13. This boxwood is infected with Volutella blight.

Figure 15JPG

Figure 14. These foliar symptoms are caused by high temperature in a greenhouse.

Figure 14JPG

Figure 15. These foliar symptoms are caused by cold injury. Photo by Mary Ann Hansen, Virginia Tech.

Figure 16jpg

Figure 16. These foliar symptoms are caused by herbicide injury.

11/5/2021 4:55:31 PM
Rate This Article:

Have a question or comment about the information on this page?

Innovate . Educate . Improve Lives

The LSU AgCenter and the LSU College of Agriculture

Top