Injecting plants with various substances has fascinated humans for many centuries. Both fertilization practices of tree injection and soil injection have been studied for decades. However, there is a constant debate on which injection method is the most suitable, effective but also most environmentally safe.
Elmsavers is phasing out the use of soil injection treatments in favour of more eco-friendly solutions. Trees generally have a better outcome when tree (trunk) injected as against soil injection.
Soil injection requires high levels of moisture at the root zone for the active ingredient to dissolve; translocation to the leaf mass is only possible when these conditions are met.
Soil injection is far more environmentally irresponsible as it wastes water and poses a significant threat to aquatic organisms: it kills earthworms at levels as low as 4ppm and it also is highly detrimental to micro-flora and mycorrhiza essential for tree nutrient uptake.
Soil injected imidacloprid can contaminate pasture and affect livestock residues, maximum residue limit is 1ppm for pasture and fodder.
By using trunk injection method to treat your tree, you are avoiding the need to irrigate and rely on adequate rainfall as the chemical will translocate within the tree regardless of the moisture in the ground.
Read our fact sheet on Soil Injection versus Tree Injection to find answers to this question.