WALLROTHIELLA ARCEUTHOBII, A PARASITE OF THE JACK-PINE MISTLETOE

Abstract

Arceuthobium, the host of Wallrothiella Arceuthobii, has been found in British Columbia, Alberta, Manitoba, and Ontario and Wallrothiella Arceuthobii has been found in Manitoba and Alberta.Arceuthobium fruits become infected in Canada in the spring, about a week after fertilization. The fungus and the infected fruits then increase in size, and they attain their maximum development by the summer of the following year.The ascospores are not violently discharged into the air. The spores ooze out into water when the perithecia are wet.The mature perithecium is made up of two compartments, the lower compartment containing the asci, and the upper compartment into which the ascospores are discharged and where they collect.It is suggested that insects are agents which disperse the ascospores.Ascospores sown in Arceuthobium decoction commence to germinate, but growth ceases after the germ tube has reached the length of about one millimetre.Attempts to inoculate the stigmas of healthy Arceuthobium with "sprout-mycelium" have so far been unsuccessful.