Trunk injection of plant protection products to protect trees from pests and diseases

An alternative to the conventional delivery methods of pesticides is needed to limit risks for consumers, users and the environment. Managing pests and diseases in orchards, forests and urban environment using trunk injection of plant protection products is a promising strategy to reduce the risks associated with spraying. This environmentally friendly method was developed in the years following the emergence of phytosanitary problems and new scientific knowledge in the field. Recently, renewed interest in the trunk injection method has emerged following the apparition of new biological control agents and technologies which are more tree-friendly. Here we compare existing injection devices and their impact on trunk injection. We focus on the advantages and drawbacks of endotherapy with respect to environmental concerns and the risks for tree and human health. We also discuss the factors that influence the effectiveness of the trunk injection including the characteristics of the agrochemicals and biological control agents, tree anatomy and physiology. The match between pest or disease occurrence and the timing of the injections also has an influence on the success of this alternative treatment method.