INTRODUCTION 



Shoot blight of western hemlock [Tsuga heterophylla (Rafn.) Sarg.] regeneration 

 in southeast Alaska (fig. 1) was observed first in 1967 on the mainland, 12 mi NNE of 

 Petersburg at Thomas Bay (Baker and Laurent 1974). Funk (1972) identified the causal 

 agent as Siroaoocus stvobitinus Preuss. He demonstrated its pathogenicity by inoculat- 

 ing young trees and reisolation from diseased tissues. Since its discovery, the disease 

 has been closely monitored by Insect and Disease Control and Timber Management personnel 

 of the Alaska Region (Baker and Curtis 1973; Baker and Laurent 1974; Baker and others 

 1975; Crosby and Curtis 1968, 1970; Curtis and Swanson 1972; Hostetler and others 197b). 

 The disease is spreading. It is now known to occur at several locations in southeast 

 Alaska as far north as Juneau. A high intensity of infection continues to exist at 

 Thomas Bay. In 1972, Sitka spruce [Pioea sitchensis (Bong.) Carr.] regeneration also 

 was observed to be affected by the disease (Baker and Curtis 1973) . 



Sivocooous shoot bl-ight of conifer seedlings and saplings is known to occur in 

 many areas of the world. Little information is available concerning its potential to 

 damage natural regeneration (Graves 1914; Kujala 1950; Lagerberg 1933; O'Brien 1973; 

 Robak 1956) . This report presents quantitative data of damage caused by S. strobilinus 

 to western hemlock regeneration at Thomas Bay, Alaska. Significance of this damage to 

 future management of these young stands is discussed. 



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