690 Journal of Agriculture. Victoria. [10 Nov., 1917. 



As a result of the inspection some twenty-five districts were found infected. 

 None of these, however, with perhaps the exception of one, could be regarded 

 as of any viticultural importance. In some centres the disease appeared in a 

 most virulent form. No damage, however, uocurred to crops or grown vines, but 

 nursery stock sufl'ered. Up to the present time the disease has been reported off 

 and on, but never as having done any damage either to growth or crops, nor has 

 it yet spread to the great vine areas in the Western Province, and the general 

 opinion is that it is not likely to, on account of the cooler climatic conditions 

 here, and where the greatest rainfall is in winter, whilst the areas that are 

 infected are situated in the midland, northern, and eastern parts of the Cape 

 Colony, which enjoy summer rains and tlie disease develops after these, when 

 great'heat gives rise to a steamy hot atmosphere, as in tropical climes. Were 

 it likely that the disease would find a home in the Western Province vineyards, 

 it must have established itself long ago, for Government regulations (copy of 

 which I inclose) to control infection are constantly ignored, and it is to the 

 writer's knowledge that boxes of grapes from a badly infected area centre, "Graaff- 

 Reinet," are brought into the vineyard centres of the Western Province for con- 

 sumption. Also specimen leaves and grapes have been sent direct to me from 

 these areas, and yet after ten years now no Western Province vineyard has been 

 found to be infected. So that if your climatic conditions are similar your growers 

 need have no apprehension. 



With regard to spraying, this was done on nursery stock at Grahamstown, 

 when the disease first appeared, but that it has become a practice in large 

 infected areas, I can safely say no. And the expense does not appear to be 

 justified, for no serious damage is caused. The fungus makes an appearance 

 when conditions suit it, and these do not seem to endure long, when it dies 

 again. 



Take the history of its discovery here. It appeared after the first heavy rains, 

 then there was a period of dry weather, the vines continued to develop, matured 

 their fruit, and after the crops had practically been gathere<l, there was rain 

 again, and again an appearance of Plasmopara, when the under-surface of the 

 leaves were a mass of down, and visible from a considerable distance; yet the 

 following years there was normal growth, and there were normal crops. The 

 quarantine restrictions are, however, still in force, but, as you notice, are not 

 strictly adhered to. 



Also in Algeria, the climate of wliich is not unlike ours, though 

 scarcely so dry, Mildew is much less feared than in France. According 

 to Eiviere and Lecq* — 



Thanks to the absence of summer rains, vegetable and animal parasitism 

 has never, even on the coast, an intensity to be compared with that observed in 

 France, especially in 1010, and it is always easy for a watchful and prudent 

 vine-grower to combat it victoriously without heavy expense. Many viticultural 

 regions at some little distance from the sea are unacquainted with Sulfatages 

 (spraying with copper mixtures), and scarcely do any sulphuring. — P. 557. 



and again, p. 806 — - 



In Northern Africa it (Downy Mildew) only causes anxiety near the coast 

 (regions of Alger, Bone, and Phillippeville), and always yields to appropriate 

 treatment properly applied. It sometimes shows itself after the end of April 

 on leaves ancl embryo bunches. The Siroco (warm south wind) checks its 

 development. 



The comparative freedom of Algeria is further instanced hy the 

 great popularity of Carignane, which was until recently the most widely 

 cultivated vine. As it is also one of the most susceptible vines to Downy 

 Mildew, it could not have attained this popularity if this disease was at 

 all prevalent. Carignane is now being superseded by other sorts, owing 

 to its rather faulty affinity for resistant stocks. 



During the past and present seasons climatic conditions on the 

 Murray have been absolutely different from those which usually prevail. 

 Thereis a very striking contrast, in nonnal seasons, at least, between 

 the climate of this region and that of even Southern France, where 



• Traite pratique d' Agriculture pour U Nord de I'Afriqlte. by Rividre and Lecq (1914). 



