556 Journal of Agricultural Research voi. xv, No. w 



data do not justify a final statement on the relative importance of the 

 different parasites. 



(5) The following fungi have indicated inability to cause damping-off 

 of pines: Aspergillus sp. (the ordinary black type); Penicillium sp. (the 

 ordinary green type) ; a rapidly growing species of Mucor from damped- 

 off seedlings and seed-bed soil; Trichotheciwm roseum; Fusarium acumi- 

 natum; Rosellinia sp. from nursery soil ; Chaetomium sp. from maple roots; 

 Phoma betae; the species of Phoma which causes red-cedar blight; and 

 a third species of Phoma from pine in Montana. 



(6) At least with some of the fungi found parasitic, heavy inoculation 

 and heated soil so favor parasitism that past experiments, mostly con- 

 ducted under such conditions, do not constitute an entirely reliable basis 

 for deciding what goes on in the seed beds under more natural conditions. 



(7) Inoculations in autoclaved soil with certain saprophytic or weakly 

 parasitic fungi have apparently resulted in a decrease rather than an 

 increase in damping-off in some cases. 



(8) Coriicium vagum and Pythium deharyanum cause a large part of 

 the damage they do by killing seed or seedlings before they appear above 

 soil. Strains of Fusarium are less inclined to do this. Such losses are 

 often wrongly attributed to poor seed. Some of the damping-off fungi 

 are able to continue to kill the roots of seedlings after they develop rigid 

 stems, so that they do not fall over. This type of trouble is sometimes 

 confused with drouth. 



(9) Excessive heat, drouth, or bending may each cause injury closely 

 simulating damping-off. On careful examination these nonparasitic 

 types of injury can usually be distinguished from damping-off by char- 

 acters described in the last pages of this paper. 



LITERATURE CITED 

 (i) Clinton, G. P. 



1913 ? NOTES ON PLANT DISEASES OF CONNECTICUT. EVERGREENS. In Conn. 



Agr. Exp. Sta. Rpt. 1911/12, p. 348-349. 

 (2) 



1916. NOTES ON PLANT DISEASES OF CONNECTICUT. RmzOCTONIA BLIGHT, COR- 

 TICIUM VAGUM VAR. SOLANI BURT (rhiZOCTONIA SOLANI KUHN). In 



Conn. Agr. Exp. Sta. Rpt. 1915, p. 450. 



(3) Cook, Mel. T. and Taubenhaus, J. J. 



191 1. TRICHODERMA KONINGI THE CAUSE OP A DISEASE OF SWEET POTATOES. 



In Phytopathology, v. i, no. 6, p. 184-189, pi. 27-28. 



(4) DiEHL, W. W. 



1916. NOTES ON AN ARTIFICIAL CULTURE OF RHIZOCTONIA CROCORUM. In Phy- 

 topathology, V. 6, no. 4, p. 336-340, illus. 



(5) Dubois, Albert. 



1906. REJAPPARITION EN ARDUENNE DE LA ROUILLE COURBEUSE DU PIN. In 



Bul. Soc. Cent. Forest. Belg., ann. 13, livr. 11, p. 661-667, iHus. 



(6) DuGGAR, B. M., and Stewart, F. C. 



I901. THE STERILE FUNGUS RHIZOCTONIA AS A CAUSE OF PLANT DISEASES IN 



AMERICA. N. Y. Cornell Agr. Exp. Sta. Bul. 186, p. 51-76, fig. 15-23. 



