Cylindrocladium Leaf Spot

• Cylindrocladium leaf spot of holly is a fungal disease that affects foliage and reduces vigor of the plant. The fungus favors warm and humid weather conditions for infection. Symptoms of infection consist of circular yellow spots, defoliation, branch dieback and reduced vigor. As the disease progresses, the spots enlarge and turn brown with purple to black borders. Destroy infected fallen leaves and prune infected branches to reduce the spread of the disease. Spray chemical fungicides during the early spring to prevent and control Cylindrocladium leaf spot.
  
  

Botryosphaeria Canker

• Botryosphaeria canker is a minor disease of holly branches and foliage, caused by Botryosphaeria fungi. The disease favors stressed hollies, unseasonably warm or cold temperature conditions and drought for infection. Symptoms of infection consist of yellowing foliage, twig and branch girdling, leaf drop and discolored bark tissue. Avoid injury to holly by practicing proper pruning techniques and avoid planting holly in poorly drained soil to prevent infection. The canker rarely causes serious damage to holly; therefore, chemical fungicides are not warranted for control.
  
  

Nematodes

• Nematodes are microscopic roundworms that cause serious damage to holly. Nematodes feed on holly roots, which cause yellow foliage, premature leaf drop, branch dieback and plant death. Infections typically occur during the late summer and early fall. Nematodes live in soil and favor hollies weakened by disease or poor growing conditions for infection. Private and university-based labs can test soil samples for nematode activity. Maintain plant vigor by practicing proper watering, fertilization and pruning dead branches to prevent infection.
  
  

Chlorosis

• Chlorosis of holly is a maintenance problem, caused when soil pH is too high and the plant does not receive enough nitrogen. Holly plants prefer slightly acidic soil, with a pH level below 7.0. Soil pH measures how acidic or alkaline soil is, where a pH above 7.0 represents alkaline soil, pH below 7.0 represents acidic soil and a pH level of 7.0 is neutral. High pH levels make it hard for holly to absorb nitrogen, resulting in chlorosis. Symptoms of chlorosis consist of leaf yellowing. Apply nitrogen-rich fertilizer during the summer months to control chlorosis.