Menkis, A., Vasaitis, R., Östbrant, I.-L., Pliūra, A. and Stenlid, J. 2017. Tests with Wood-Decay Fungi to Control Sprouting from Cut Stumps Infected by Dutch Elm Disease. Baltic Forestry 23(1): 270-273.

   The Dutch elm disease pathogen Ophiostoma novo-ulmi in year 2005 invaded the Swedish island of Gotland, which possesses large and valuable population of elms. The control of the disease is accomplished when infected elms are harvested and destroyed, and stumps are treated with the glyphosate herbicide to kill the stumps and the root systems, and prevent further spread of the disease to the neighbouring trees via root contacts. The aim of the present study was to test an alternative method to control the stump sprouting by deploying two species of saprotrophic wood-decay fungi as biological control agents. The study was carried out during three consecutive years 2014, 2015 and 2016. Fungal inoculum of Chondrostereum purpureum and Stereum hirsutum was prepared by cultivating vegetative mycelia in liquid nutrient medium and then formulating into a gel. Each year, the inoculum was applied at the beginning of the growing season on the surface of fresh stumps. In total, 250 stumps were treated with saprotrophic wood-decay fungi and 250 stumps were left as non-treated control. Assessment of stump mortality was carried out ones after each growing season. Results showed that the mortality of stumps (without living sprouts) was low in each treatment and year (between 4.1% and 25.6%) and did not differ significantly from those in the control. In conclusion, the meth-od tested had very limited or no effect on the mortality of elm stumps, and thus, appears to be unsuitable to control the spread of Dutch elm disease via root contacts and sprouts.

Keywords: biological control, Dutch elm disease, Ophiostoma, saprotrophic wood-decay fungi, sprouting control, Chondrostereum, Stereum.