Canadian Forest Service Publications
Effect of selected forestry herbicides on ectomycorrhizal development and seedling growth of lodgepole pine and white spruce under controlled and field environment. 1990. Sidhu, S.S.; Chakravarty, P. European Journal of Forest Pathology 20(2): 77-94.
Issued by: Northern Forestry Centre
Catalog ID: 11321
In tests under aseptic conditions, the herbicides hexazinone (PrononeTM5G® and Velpar L.R.®), glyphosate, and triclopyr reduced seedling growth and mycorrhizal development of Pinus contorta var. Litifolia and Picea glanca. Triclopyr was most toxic of the tour herbicide formulations. Under greenhouse condition, only 2 formulations of hexazinone (Pronone TM5G® and Velpar L.®) were tested. At high concentrations (2 and 4 kg/ha) it reduced growth and mycorrhizal infections significantly but showed recovery with time. No adverse effects were observed at low concentration (1 kg/ha). In general, seedlings inoculated with mycorrhizal fungus (Suillus tomentosus), were more sensitive to herbicide than the ones without mycorrhizal inoculation. Under field conditions overall effects of herbicide application were less intense. Only 4 kg/ha rates of hexazinone resulted in reductions in seedling growth and mycorrhizal infections. The nonmycorrhizal seedings planted in the field developed mycorrhizae in over 40% of short roots within 2 months after planting in all herbicide treatments.