64 



BULLETIN 934, U. S. DEPARTMENT OF AGRICULTURE. 



Table VIII. — Results of inoculations with miscellaneous oomycetes on pines in 

 autoclaved soil at the time of sowing — Continued. 





Num- 

 ber of 

 pots. 





Results. 





Experiment number, hast, and inoculating fungus. 



Emerged. 



Damp- 

 ing-off. 



Survival. 



No. 68, Pinus resinosa: 

 Phvtophthora sp. — 



Strain 358 



5 

 5 

 5 

 5 



5 

 5 

 5 

 5 

 5 

 5 

 18 



3 

 3 



2 

 3 

 3 

 16 



3 

 3 



3 



2 



2 



14 



Per 5-pot 

 unit. 

 104 

 109 

 98 

 121 



122 



120 

 96 



110 

 94 

 84 



104 



Per 3-pot 



unit. 

 20 

 62 



45 

 37 

 40 

 35 



8 

 13 



11 



29 



6 



9 



Percent. 

 7 



18 

 5 

 



1 

 9 

 5 

 6 

 1 

 2 

 



35 

 



7 







25 



5 



50 

 8 





 6 

 

 



Per 5-pot 

 unit. 

 97 



Strain 372 



89 



Strain 375 



93 





121 



Pvthium artotrogus (?), Washington, D.C.— 



Strain 821 



121 



Strain 823 



109 



Strain 831 



91 



Strain 832 



103 



Strain 833 



93 



Undetermined Phycomvcete 



82 



Controls 



104 



No. 72A, Pinus resinosa: 

 Phvtophthora sp.— 



Strain 372 



Per S-pot 

 unit. 

 13 





62 



Pythium artotrogus (?), Washington, D. C— 

 Strain 821 



42 



Strain 831 



37 



Strain 833 



30 





33 



No. 72B, Pinus ponderosa: 



Phvtophthora sp 



4 





12 



Pythium artotrogus (?), Washington, D. C. — 



Strain 821 



11 



Strain 831 



27 



Strain 833 



6 



Controls 



9 







OTHER FUNGI. 



Data on the possible relation between various other fungi and the 

 damping-off of conifers have been already summarized by Hartley, 

 Merrill, and Rhoads (68, p. 546-550). Pestalozzia funerea on the 

 basis of the experiments of Spaulding (135), Botrytis cinerea on the 

 basis of observation and very preliminary inoculations, and Tricho- 

 derma koningi on cultural evidence only are all believed to be po- 

 tential causes of damping-off, though not ordinarily important. Al- 

 ternaria sp. is under a certain amount of suspicion on account of its 

 frequent association with the damping-off of conifers, but it has 

 never been used in experiments. Rhizopus nigricans (incorrectly re- 

 ported as Mucor), Trichothecium roseum, Rosellinia sp. from nursery 

 soil, Chaetomium sp. from maple roots, strains of Penicillium and 

 Aspergillus, Phoma betae, and Phoma spp. are all reported to have 

 been used in inoculations with negative results. 



Since the publication of the above summary a preliminary success- 

 ful inoculation experiment with Botrytis cinerea. on recently emerged 

 Pseudotsuga taxifolia has been found briefly mentioned in an article 

 by Tubeuf (140) on another disease. Further experiments with v;i- 



