NOTES AND ABSTKACTS. 



26? 



Potatos, Seed, Destruction of Blight Fungrus by Heat. By 



1). McAlpine (Jour. Dep. Agr. Vict., November 1909, p. 700).— ' If the 

 seed tubers are suspected, or in order to make certain that the fungus 

 is destroyed, they may be sterihzed. The ordinary steriUzing of the 

 surface will not serve the purpose, for the fungus is inside the potato; 

 but Jensen has devised an effective method of treatment. This consists 

 in subjecting the seed potatos to a dry heat at a temperature of 120° F., 

 not allowing it to fall below 118° nor to rise above 132°. I had some 

 diseased potatos kept at a temperature of 110° F. for four hours, but 

 afterw^ards they produced a luxuriant crop of the fungus in twenty-four 

 hours, while at 120° the spawn of the fungus was destroyed. I have 

 had an apparatus constructed consisting of a copper cylinder, with a 

 movable basket inside capable of containing a bushel of potatos, and 

 surrounded by a jacket of water kept, when necessary, at the proper 

 temperature. After this treatment the germinating power of the tubers 

 is rather improved than otherwise. " — C. H. H. 



Potatos, Seed, Disinfected by Formalin {Jour. Dep. Agr. Vict., 



November 1909, p. 700). — Seed potatos may be simply disinfected by 

 placing them in a loose bag and then steeping them in a solution of 

 formalin for two hours. A 1-lb. bottle of the proper strength, costing 

 Is. 6d., is added to 32 gallons of water, and, after stirring, it is ready 

 for use. — C. H. H. 



Potatos, Sprain in {Jour. Bd. Agr., xvi. 1, p. 33; 8, p. 647).— 

 When the potato is cut through the middle, brown spots, like the 

 currants in a scone, show the presence of the disease. On cooking, 

 the spots can be picked out like pellets. 



The cropping of the potatos is not affected, and the ailment is found 

 in well-proportioned tubers. Some observers have found the haulm 

 of the potato darkened and covered with a white scale when the tubers 

 are beginning to be attacked. The ailment develops in the pit, and is 

 often scarcely noticed in a crop before storing. Dry, hot seasons, 

 gravelly and sandy soil appear to favour the disease. 



The experiments ' carried out at Kew, and the material submitted 

 for examination, make it impossible to formulate a diagnosis of the 

 disease. The most constant symptom is the presence of small, rust- 

 coloured spots scattered in greater or less abundance throughout the 

 flesh. 



Where mycelium is present in the tissue of the brown spots * ' winter 

 rot " caused by Nectria solani (Eeinke) always develops. It is not at 

 all probable that two distinct diseases presenting similar symptoms — 

 rust-coloured spots — are present in potato tubers, and it would therefore 

 appear that the disease is an incipient stage of " winter rot," which, 

 for some reason, has been arrested in its preliminary stage. There is 

 said to be the constant presence of an obscure organism accompanying 

 " internal disease " in potatos, but for further information develop- 

 ments must be awaited. — J. S. 



