DISEASES NOT DUE) TO PARASITES OR OF UXKXOWN ORIGIN I373 



logically alkaline manures such as Chilean nitrate, basic slag and lime. It 

 may therefore be controlled by manures with a physiologically acid reaction, 

 such as ammonia, potash salts and superphosphate. This hypothesis is 

 born out bj^ the writer's experience of soils that are most favourable to the 

 disease. 



It is intended to continue the experiments. 



1029 - The Possibility of Recovery of the Slips of a Vine suffering from " Bramble- 

 Leaf" (i). — Pantan'elli E., in Lc Stazitmi spcrimcnliili italitdu, Vol. X1,1X, I'art 5-6, 

 pp. 249-296. Modena, 1916. 



Experiments carried out for the purpose of ascertaining : 



i) Whether the wood taken from vines suffering with " Bramble- 

 leaf (court-noue " or " roncet ") produces in all cases plants and vines 

 showing the same disease ; 



2) Whether vine plants affected with bramble-leaf can be cured by 

 suitable treatment or under favourable conditions of growth ; 



3) Whether such recovery is real and diu'able or apparent and 

 transitor}'. 



In the course of these experiments the following facts were brought 

 to hght : 



Slips taken from vines affected with this disease and planted in any soil 

 began their spring growth by forming buds which exhibited bramble-leaf. 



The disease of the shoots, slips or plants consisted mostlj^ in deformation 

 of the leaves (laciniation, twisting of the toothed edges, spotting in the 

 case of Riparia and Rupestris, asymmetry and formation of blisters on 

 the leaves in Berlandieri) and in a strongW pronounced internodal distor- 

 tion of the branches. In the spring, above all in the case of Rupestris, Ri- 

 paria, 420 A, the leaves showed pale or blackish spots, but never to the same 

 extent as in the parent vines suffering with mosaic bramble-leaf. I^eaves which 

 had grown from the month of May onwards, although deformed, were ge- 

 nerally without these spots, which sometimes reappeared on the last leaves 

 the growth of which had taken place at the end of autumn (November- 

 December) : they then also appeared on some of the last leaves of plants 

 remaining healthy in appearance. These symptoms are identical with those 

 produced b^' rapid falls of temperature during the formation of the buds. 



The slips taken from vines attacked by bramble-leaf often recover in 

 the course of growth ; precisely the same thing, for that matter, is observed 

 in the parent vines, that is to say, after a first stunted development the bran- 

 ches form internodes which grow continually longer and end by being of 

 normal form ; the leaves were less and less deformed and their shape and 

 dimensions at last became normal. 



It is a rare thing for slips taken from vines suffering with bramble- 

 leaf not to have stunted buds suffering from the disease at the outset. 

 When this case did occur, especially in Berlandieri and its hybrids as well 

 as the European-American crosses, it is explained by the fact that the slip 

 has been taken from the non-diseased tip of a branch. 



(!) Sjc also B. July loi.;, Xo. 6.S4. {Ed.) 



