Fluid Delivery in Injected Ring-Porous Trees

Abstract

In ring-porous trees such as elm, oak, and ash, trunk injections of fungicides for control of vascular wilts should be specifically directed to the single outermost growth ring of wood. It transports the most water and is the first to become infected by fungal wilts. Shallow-pit Injection taps into this target tissue and is enjoying widespread use among arborists and researchers. Evidence to its effectiveness comes from theoretical, laboratory, and clinical studies. The need now is to quantify spread of trunk-injected fungicide in the crown. Gas chromatography and mass spectroscopy clearly detect thiabendazole (TBZ) from samples containing 1 part per million TBZ. This sensitive means of detecting fungicide in crown tissue is essential to optimize TBZ dosages, minimize injection injury, and to detect TBZ persistence in outermost wood of twigs years after injecting the trunk.