CERTAIlSr MimiR DISEASES. 13 



purport. The trouble is frequentl}^ observed, and is most commonly 

 termed "sprain." It is not propagated in seed or soil and is non- 

 parasitic. It is considered to be the direct result of malnutrition 

 associated with unfavorable soil conditions, resulting either from too 

 dry conditions or from the lack of potash or lime. It is frequent in 

 light, dry soils during dry seasons, and is never seen on heavy, strong, 

 moisr soils. The remedy, in the judgment of the specialists cited, lies 

 wholly in attention to cultural conditions and the choice of varieties. 

 Some varieties are more liable than others to internal brown spot 

 and should not be used on soil that favors the disease; e. g., Mr. Scar- 

 lett stated that the British Queen variet}^ is especially predisposed to 

 "sprain.'' The primary remedy, however, lies in selection and treat- 

 ment of the soil — i. e., in avoiding dry soil — and in so cultivating as to 

 conserve moisture, while using lime and potash liberall3^ 



FILOSITE, OR GROWING-OUT. 



The names "iilosite" and "growing-out" are applied in France'* 

 and England, respectivel}^, to various forms of secondary outgrowths 

 from tubers. Examples that were shown to the writer were in some 

 cases merel}' "prongy" tubers, while in others stolons starting from 

 the eyes produced secondary small tubers. Delacroix describes con- 

 ditions where the seed tubers send out an abundance of weak shoots, 

 both above and below ground, but these soon die without yielding any 

 crop. The latter type is therefore allied to the curl disease of the 

 potato.* The less serious forms of growing-out are attributed to cli- 

 matic and soil conditions, especially to a long, wet autumn following a 

 dry summer. The more serious types of the disease, especially as occur- 

 ring in France, are attributed to varietal weakness or "running out." 

 In both France and England the use of seed from an}'^ plants showing this 

 tendency was condemned as tending to give a crop of generally reduced 

 vitality. 



LEAF-SPOT. 



Since there has been a difference of opinion among pathologists as 

 to the occurrence and destructiveness of the fungus Alternaria aolani 

 in Europe, the writer was led to keep an especially close watch for it. 

 Prof. P. Sorauer kindly sent specimens from Europe some years ago 

 corresponding fully with the leaf -spot disease caused by this fungus, 



« See Delacroix, G., Sur la filosite des pommes de terre, Jour, de 1' Agriculture, 

 December, 1903. 



''Frisolee (French), or Kriiuselkrankheit (German), is a common but not very 

 serious potato malady of Europe, of which the cause is not clear, but apparently it 

 is associated with varietal weakness and malimtrition. It is characterized by dwarf- 

 ish plants bearing an excessive number of rather undersized leaves, which are down- 

 curled and brittle. The tops have thus a dense or bushy appearance. They may be 

 quite as green as normal plants. 



