A semipopular account of R. pseudotsugae by Wollenweber and 

 Richter (71) was published in 1932. This gave the distribution of 

 the disease in Germany, the symptomatology and life history of the 

 fungus, method of infection, and recommendations for control. 



In 1933, Liese (30) publicly repudiated his ideas of direct control 

 consisting of trimming and burning infected branches and accepted 

 Geyr's (19) proposals for locating resistant varieties and developing 

 experimental nurseries. This was prompted by the continued rapid 

 spread of R. pseudotsugae in Douglas-fir plantations in Germany. 



Rohde (45) continued his efforts to learn the date of introduction 

 of R. pseudotsugae into Germany and delimited the distribution of 

 the disease in that country. He determined the primary infection 

 date to be 1922, and in 10 years the fungus had spread to a reported 

 27 silvicultural districts. He emphasized the need of meteorological 

 studies coupled with data on the rate of spread. Rohde (45) also 

 mentioned the differences in susceptibility of the strains of the host 

 to the needle cast fungus but suggested that such differences were 

 greatly exaggerated. He denounced the practice of cutting diseased 

 trees as a control measure because of the large areas and numbers 

 of trees involved. 



In a paper on the mechanics of needle cast in Douglas-fir, Rohde 

 (46) in 1934 rejected Liese's explanation for the lack of infection on 

 the green strain. Even though needles of this strain developed later 

 than those of the grey and blue strains, ascospores were found a 

 month after the bursting of the late developing buds. He concluded 

 that lateness in shoot expansion of the green strain was not entirely 

 responsible for its immunity, but that other factors, such as favorable 

 site and water retention had important effects on the susceptibility 

 of a tree to R. pseudotsugae. 



Van Vloten (64) traced the long-distance dissemination of the 

 fungus on four-year-old Douglas-fir in Holland and found that they 

 had been infected upon arrival from a forest nursery in northern 

 Germany. 



Liese (31) and Rohde (47) both published on the relative suscep- 

 tibilities of the various strains of the Douglas-fir in 1936. They 

 concluded that the green strain was not infected as commonly as 

 the other strains. 



Kanzow (25) found that, for all practical purposes, the green or 

 coastal form of the Douglas-fir could be considered immune. He 

 proposed a scale for such immunity based upon the altitude of the 



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