no apparent ill effects from the spray. Although fungus stimulation 

 by the spray may have caused the excessive injury, it is more likely 

 that the new foliage was injured by the Captan. Some Captan- 

 sprayed trees produced very little new growth in the spring of 1957, 

 one year after spraying, but a definite relationship could not be 

 drawn. It was not felt that the Captan was effective enough to be 

 continued and hence was not used in the Vermont studies. 



Cyprex was used only in the Vermont phases of the control 

 studies in plantations where both the Rhabdocline and Adelopus 

 needle cast diseases were serious. The first applications were made 

 in 1958 on June 2 and 3 due to the late development of Douglas-fir 

 buds in the Jericho and Woodstock areas. A second application after 

 10 days completed the test. The foliage of these trees appeared to be 

 a little greener than that of the surrounding unsprayed foliage for 

 the summer and fall months. By late October, however, this differ- 

 ence had vanished and infection by R. pseudotsugae appeared to 

 develop as strongly as on the unsprayed trees. By April of 1959, not 

 one of the 30 trees (15 each at Jericho and Woodstock) yielded 

 evidence of any degree of Rhabdocline control. 



The cycloheximide derivatives, Actidione BR and Actidione S 

 were used in the Vermont test plots only. The use of Actidione BR 

 at the recommended concentration of 0.001 per cent proved far too 

 toxic to the tender young foliage at the time of bud break and thus 

 resulted in complete and irrevocable burning of the 1958 foliage. 

 The concentration was reduced to 0.0005 per cent for the 1959 trials, 

 resulting in only a slight burn to some of the new growth. The effec- 

 tiveness of Actidione BR as a control for Rhabdocline needle cast 

 has not been evaluated to date. 



The use of Actidione S analog of cycloheximide for foliar appli- 

 cation has followed the unhappy results of the 1958 tests with 

 Actidione BR. Since the S analog was applied in late May and early 

 June of 1959, the life cycle of R. pseudotsugae is but partially 

 complete and the effectiveness of the spray cannot be ascertained as 

 yet. Inasmuch as the cycloheximides are eradicant sprays, there 

 might possibly be more hope for this essentially different approach 

 to control than for a continuation of protectant spray trials. 



Relatively few other spray materials have been used or even 

 recommended by others to combat R. pseudotsugae. Weistaner (68) 

 used Phygon (2, 3-dichlor-l, 4-napthequinone) at two teaspoons per 

 gallon of water but with no success. Various concentrations and 



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