674 journal of Agriculture. Victoria. [10 Oct., 1911. 



the number of vines thus attacked is usually very small — only an isolated 

 \ine dies here and there, irregularly throughout a block. Even in seasons 

 when it is most prevalent, the total number of vines affected is inconsider- 

 able. Vines in robust health are more aj)t to be struck (Jown in this 

 way than weaker ones. In fact, it is on rich soil, where moisture is 

 abundant, that the most severe xisitations have been experienced. Mid- 

 summer, or from the 15th. July to 15th August in France (15th January 

 to 15th February in Australia) is the season when apoplexy is most frequent. 



The disease has long been known in France. It was described at some 

 length by H. Mares in 1862, or in pre-Phylloxera days, as occurring 

 on ungrafted vines. It appears, however, to occur rather more frequently 

 since retx)nstitution on resistant stocks. The greater the affinity between 

 stock and scion, the less frequent is this accident. With the usual stocks 

 now in use, such as Rupestris du Lot, the Riparia. Rupestris Hybrids, 

 &c., it is rare for many cases to be noted in a vineyard — with some of 

 the older stocks it was much more frequent. Liability tO' apoplexy is 

 the main reason which led to the abandonment of Riparia Grand Glabre, 

 for example. This st<x;k, when grafted with Alicante Bouschet, suffered 

 in some cases to such an alarming extent that a new disease was suspected, 

 called, for want of a better name, ^^ Maladie de rAlicante-Bouschef.'" 

 With Riparia Gloire, apoplexy is less frequent, though more so than with 

 the stocks now gradually superseding it in France, and which we are 

 now propagating in Victoria. 



The cause of this alarming accident, as it is usually considered (in 

 contradistinction to a disease), has long been looked upoa as obscure. 

 The usual explanation is that it is the result of a rupture of equilibrium 

 between the water absorbed from the soil by the roots and that transpired 

 by tlie leaves. Climatic influences seem to have much to do with the 

 occurrence. It is most frequent when dry sunny weather follows imme- 

 diately after a close muggy spell ; especially when there is abundant 

 moisture in the soil. During the close weather, transpiration is less active 

 and the roots, becoming accustomed to sending up a small supply of 

 moisture, then fail to respond quickly enough to the call made upon them 

 when dry, hot atmospheric conditions suddenly supervene. At any rate, 

 this explanation has long been the generally accepted one. Professor 

 Vialla says : — * 



It appears . . . that this surltlen death is due to a rupture of equilibrium 

 between transpiration by the leaves and absorption by the roots. Water, being 

 too abundant in the soil, the leaves could not in the moist atmosphere transpire 

 the excess carried to the leaves imder the influence of very hot weather. But, more 

 often, Folletage seems to be due to the roots not being able to supply the leaves 

 with as much water as they- evaporate. These two opposite causes would lead to 

 the same result. 



M. Ravaz, in a recently published article,! attributes vine apoplexy 

 to a Polyporus or tinder- forming fungus ; probably Poly for us igniarius, 

 which he has found in many of the dead vines. M. E. Vinet has likewise 

 found allied fungi on vines, which have died in a similar manner, in 

 the Anjou district. Two species found. by him were identified as Poly- 

 porus versicolor and Stereum Itirsutuin.X It would thus appear that 

 apoplexy is, in some cases at least, due to a parasite. 



Though apoplexy may, and probably will, be occasionally observed 

 in Victorian vineyards, it need not cause alarm. § Our climatic conditions 



* Les Maladies de la Vigne, p. 472. t Progres Agrkole. "tli November, 1909. 



} Revue de Viticulture, 16th Becember, 1909. 

 § Some isolated cases very much resembling apoplexy have been brought under the writer's notice 

 in the Goulburn Valley — only a very few vines were affected. See Journal, 10th October, 1908. 



