Pflanzenkrankheiten. 335 



Harter, L. L., The foot-rot ofthe Sweetpotato. (Journ. Agr. 

 Res. I. p. 251-274. pl. 23—28. 1 textfig. Dec. 10, 1913.) 



A wound-disease of the southern states, caused by Plenodomus 

 destruens. Trelease. 



Hartley, C. and T. C. Merrill. Preliminary lests ofdisin- 

 fectants in Controlling damping -off in variousnurserj' 

 soils. (Phjrtopathology. IV. p. 89—92. 1914.) 



A brief description of some preliminary tests of the work, that 

 disinfectants do in Controlling damping-off disease. It seems from 

 the work so far done that for preventing the daraping-off of conifers 

 sulfuric acid is the best disinfecting agent on most soils, as regards 

 convenience, economy and effectiveness. This should be applied in 

 sowing time. It has proven more successful than heat wherever 

 both have been tested, as it affords less chance for troublesome 

 reinfection. 



Dicotyledonous weeds which occur in the pine seed-beds have 

 seemed much more susceptible to acid injury than have the pines. 

 Therefore for many soils in which truck crops are to be grown, 

 it is doubtful if the acid will be practicable for use alone. In two 

 of the experiments, acid disinfection has been followed by application 

 of air-slaked lime. This treatment appears to disinfect the soil without 

 injury to plants subsequently grown in it. But like heat sterilization 

 it allows reinfection and because of the importance of reinfection, 

 in some cases neither heat nor acid-neutralized treatments have 

 been satisfactory. For non-alkaline soils in which heat sterilization 

 is effective it seems very likely that equally good results can be 

 had b}'' disinfecting with a sufficient sulfuric acid Solution a few 

 days before sowing and then neutralizing with lime just before 

 sowing. Sufficient neutralization should be secured in most soils by 

 raking into the surface soil an avoirdupois ounce of air-slaked lime 

 for every fluid ounce of acid used. For soils on which sulfuric acid 

 is not an efficient disinfectant, zinc Chloride and copper sulfate have 

 indicated greater efiiciency against parasites than formalin, and are 

 well worth testing in general soil disinfection work. 



M. J. Sirks (Haarlem). 



Heald, F. D. and M. W. Gardner. Longevity ofpycnospo- 

 res of the chestnut-blight fungus. (Journ. Agr. Res. IL 

 p. 67—75. Apr. 15, 1914.) 



Pycnospores of Endothia parasitica withstand drying for as 

 much as 119 days; and it is believed that in the soil adhering to 

 nursery stock large numbers of these spores may remain viable 

 during long periods of shipment. Trelease. 



Heald, F. D. and R. A. Studhalter. ßirds as carriers ofthe 

 chestnut-blight fungus. (Journ. Agr. Res, IT. p. 405—422. pl. 

 38—39. 2 textfig. Sept. 21, 1914.) 



Though birds with adherent spores of Endothia parasitica are 

 not held to be relatively important agents in local distribution of 

 the disease, isolated foci at a distance are held to be explicable on 

 the theory that pycnospores may be carried by migratory birds. 



Trelease. 



