MUI. BERRY-DWARF TROUBLES IN JAPAN. 



223 



cause of the disease. But as my observation became more ex- 

 tensive, I found that in many diseased plants there was no putre- 

 faction, and also that it was not generally observed in the first 

 stage of the disease. So it is very probable that this putrefac- 

 tion is only a secondary phenomenon accopanying the disease and 

 not its primary cause. Nevertheless the putrefaction unavoida- 

 bly accelerates the disease and hastens the death of the whole 

 plant. Further, the sap flowing out from the cut stems may 

 be a good nourishment for small orgamsms. As the sap is very 

 abundant in Takasuke, Tsuruta etc, it is natural that these 

 varieties are especially prone to putrefaction. 



Again many believe that the principal cause of the disease 

 lies in the decay of the roots. It is true that the roots of the 

 diseased plants are generally in a very bad condition, the small 

 roots having almost entirely decayed ; but at the beginning of 

 the disease, the roots are generally quite normal. Moreover, if 

 the decay of the roots be the cause of the disease we could not 

 understand why those plants which are not subjected to cutting 

 are entirely free from the disease. 



It is very interesting to see whether other plants are also liable to the same disease 

 when subjected to repeated cutting or when frequently robbed of their leaves ill the 

 growing season. Japanese Salix is cultivated in Tanba and Tango just in Ihe same 

 manner as the mulberry, but the stems are cut in late autumn when the leaves have 

 fallen down. This is a very rational mode of precedure and entirely in harmony with the 

 teachings of plant physiology, and we have never observed the disease in this plants. 



Japanese tea plant is generally subjected to frequent picking of the leaves, sometimes 

 even 3 or 4 times in a year, and we observe very often that in such a case the leaves be- 

 come smaller and can not develop well, and that sometimes even the \\ hole plant dies ; 

 but the disease is soon healed by good manuring. 



