Elytroderma deformans . [Descriptions of Fungi and Bacteria

Abstract

Abstract A description is provided for Elytroderma deformans . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Pinus banksiana, P. contorta var. latifolia, P. echinata, P. edulis, P. jeffreyi, P. ponderosa . DISEASE: Witch's broom of pine. Trees of all ages, but mainly those over eleven years old and up to six metres high can be attacked. Current year needles are infected, and gradually discolour (though parts may remain green) over the winter, the discoloration being most marked by the following May, when the imperfect stage is formed. Ascocarps begin to form in June and ascospores are shed over the following winter, with a peak in October corresponding to the start of the rains. Needles killed by the disease are usually shed at about this time. Needles older than one year seem to be immune from infection. Shoots bearing infected needles form characteristic witch's brooms usually about 60 cm diam., but occasionally up to 2 m diam. Unusual resin cysts may be found in the phloem zone of the bark of these brooms, and the fungal hyphae can permeate the woody tissues. GEOGRAPHICAL DISTRIBUTION: North America (Canada: British Columbia, North West Territories, Ontario, USA; Arizona, California, Colorado, Idaho, Montana, Oregon, Washington). TRANSMISSION: By air-borne ascospores in humid or wet weather, also apparently from infected needles, by hyphal growth through the woody tissues into the buds.