345 

 Forked Growth of Vines. 



It may be noticed in various localities, that different varieties of vines 

 assume a tendency to excessive branching and retain it hereditarily. The 

 kind of false ramification appears as a forking of the vines and such dis- 

 eased plants are usually Httle if at all productive. Rathay^ published the 

 most thorough observations on this subject and corroborated these state- 

 ments in lower Austria. The wine growers there, who call these branch- 

 sick vines "Forks," or "Double tipped/' state that the forked formation may 

 commence in very different places. The vines which in adjacent 

 groups • usually begin showing this abnormal direction of growth, 

 first develop scattered forked branches and in this way present a "spurious 

 forking" as may be seen everywhere in luxuriant vineyards. This initial 

 stage of the disease is not dangerous, since the plants frequently return to a 

 normal growth. The danger begins with the spread of the disease over the 

 whole plant. Correlated with this is the transmissibility of the disease. 

 This has been demonstrated in cuttings and suckers of affected vines. 



No cause of this phenomenon can be given as yet with certainty. 

 R.athay was convinced that parasites were not present. The opinions of 

 practical workers disagree greatly. Some think that exhaustion of the soil 

 by intensive grape culture is the cause, while others are of the opinion that 

 a clogging of the soil due to heavy rain storms or to the working of the 

 soil during and soon after rain has an injurious effect. 



In my opinion this disease is a phenomenon of turning green — vires- 

 cence — i. e., a morbid increase of the vegetative development. 



Kaserer's- statements favor this hypothesis. He states that the first 

 evidences of the disease are found in the transformation of the covering 

 bract of the tendrils into a small leaf, the most advanced stage in the trans- 

 formation of all the tendrils into leafy shoots. In grape vines, the tendrils 

 are axial organs, of which the development depends upon the amount and 

 constitution of the organic building materials present. In younger vines 

 they become herbaceous shoots, but in older ones develop into inflorescences 

 at the lower buds. If all the tendrils are transformed into leafy shoots 

 the vegetative development will predominate, a morbid condition. The 

 building material present is wrongly utilized. The cell sap necessary for the 

 formation of the sexual organs is not properly concentrated. Thus far it 

 is possible to agree with Krasser", who speaks of a diseased condition of 

 the protoplasm in certain regions as a cause of this "herbaceousness." 



If Krasser, referring to the works of Kober and Gaunersdorfer (1901) 

 insists that no disturbances in conduction and no lack of nutritive sub- 

 stances can be assumed as causes of the "herbaceousness," which represents 



J Rathay, Emerich, tJbcr die in Nieder-Osterreich als "Gabler" oder "Zwiewip- 

 fler" bekannten Reben. Klosterneuburg-, 1883. 



2 Kaserer, H., Uber die sog-enannte Gablerkrankheit des Weinstocks, Mitteil. 

 d. k. k. chemisch-physiol. Versuchsstation Klosterneuburg", 1902. Part 6. ' 



3 Krasser, Fridolin, tJber eine eigentumliche Erkrankung der Weinstocke. II, 

 Jahresb. d. Ver. d. Vertreter d. angewandten Botanik. 1905, p. 73. 



