ABSTRACT
This chapter discusses several features of built environments that threaten the vitality and resilience of urban forests. It also deals with globally important pests and diseases in urban environments. Arthropod pests treated in the chapter encompass lethal borers, foliar pests, and sucking arthropods including scale insects, lace bugs, and spider mites. Specific arthropod case studies include oak processionary moth, Thaumetopoea processionea, emerald ash borer, Agrilus planipennis, and horse chestnut leafminer, Cameraria ohridella. A vast majority of tree diseases are caused by biotic agents, including viruses, phytoplasmas, bacteria, fungi, fungal-like organisms, parasitic plants and nematodes. Tree diseases often attain higher incidences and severities in urban environments compared to natural ecosystems. The reduced spacing among trees in urban landscapes may play a role in disease outbreaks. The most effective tree disease management strategies and tactics, including integrated disease management programs, are reported based on the biology of pathogens.
