Periodical Literature. 493 



the end of September. The reddening increases through the fall 

 and winter, until in April-May not a green needle may be seen ; a 

 large number of plants, however, recover themselves with green 

 shoots. When the needles fall, as yet no fruit bodies are to be 

 seen, which form later. The principal time of infection takes 

 place the end of July until middle of September, when alone 

 spraying is of use. 



A number of questions remain to be solved. The ftmgus occurs 

 also on old trees but is then comparatively harmless, seemingly 

 saprophytic. Is this a different form or species, or is there 

 danger of its propagation to be transferred to seedbeds in their 

 neighborhood and become parasitic, or are the needles of old 

 trees immune. Authorities differ, and it appears that the biology 

 of the fungus is but little known. 



By careful cultures under investigation, explained in great 

 detail, the author has been enabled to show up various fallacies 

 of Tubeuf and Mayr and develop very fully the biology of the 

 fungus, which shows it to be a parasite, to be sure, but little 

 adapted to parasitic life — just emerging from the saprophytic 

 stage ; but in its ability to penetrate into healthy needles and to 

 exist there untroubled by competitors lies its strength. 



We can from the very interesting detail select only a few 

 points. 



The fungus on old trees is the same as that which attacks the 

 young, but here, probably due to different physiological character- 

 istics, it does not do damage. Practically it is therefore desirable 

 to locate nurseries out of reach of old infested pine. Immunity 

 is gradually attained in the 7th to loth year, but needles which by 

 girdling are weakened succumb even in older trees to the fungus. 



The needles which drop in the spring are the ones that spread 

 the disease in late summer. The infection takes place within a 

 short time. Only on young plants are the healthy needles at- 

 tacked, — it is an infantile disease. 



By spraying only those spores may be rendered innocuous, 

 which have located a few days before or those which locate while 

 the liquid hangs on. Spraying is of use only on older seedlings. 

 The needles of yearlings are covered by a fine waxy cover which 

 prevents the spray from sticking. An attempt, successful, to 

 first dissolve this waxy film by soap or other solvents, which per- 

 mitted the spraying mixture to hang on well, led to a drying up 



