The viburnum shrub -- some varieties are considered small trees -- rarely suffers from disease or insect infestation unless it is otherwise stressed or unhealthy. Fatal afflictions are possible, however.
The viburnum leaf beetle possesses a voracious appetite and can defoliate entire shrubs, according to Cornell University. A viburnum that has endured a heavy infestation for two or more years could be fatally infected. The beetle is best managed by removing egg-infested twigs and introducing natural predators such as adult ladybirds.
Additional pests such as aphids feed on viburnum leaves and require control through the use of insecticidal soap or horticultural oil. Additionally, thrips can weaken and damage a ciborium, with the removal of grass or weeds in the vicinity helping to manage the thrip population. Spider mites on viburnum are controlled with persistent, strong sprays of water.
Viburnums are susceptible to collar, root and crown rots, leaf spot diseases, and powdery mildew, according to the University of California Integrated Pest Management System. Botryosphaeria dieback and canker can prevent leaf production in the spring. Most of these diseases are preventable if the shrub is otherwise healthy.