Macrophoma can cause leaf blight, but it usually acts as a weak pathogen. Paecilomyces buxi has been consistently associated with roots of English boxwood exhibiting the syndrome of boxwood decline. Symptoms consist of weak and spindly plants. Dead or dying branches occur randomly in the bush. The older leaves drop prematurely and the remaining foliage develops a yellow color.
Leaves often have pink eruptions of spores on black fruiting bodies.
Dead areas or cankers develop along branches or near the crown. Samples for root disease should be submitted to the Clemson University Plant Problem Clinic for analysis. Crowded growth and dead leaves in the branch crotches tend to maintain high levels of humidity in the canopy, making conditions conducive to dieback diseases. Prune dead stems back to healthy tissue. Removal of dead branches and leaves from crotches of the plant, as well as yearly renewal of mulch material, will also aid in control.