20 The Spraying of Plants. 



on the leaves of Jacquez grapes at Coutras and also received it 

 from various departments of Lot-et-Garonne, and of Rhone. 

 The disease spread rapidly and was so destructive that in 1882 

 the fruit in many vineyards was almost entirely destroyed. The 

 climate of France appears to be peculiarly adapted to the 

 growth of this mildew, which nourishes as well upon the varie- 

 ties of Vitis vinifera as upon our American species. In moist 

 seasons it is fully as energetic as in America, or even more so. 

 The leaves fall from the vines, and the grapes are thus prevented 

 from ripening properly. Even in cases in which the vines do 

 not lose all their foliage, a partial reduction is sufficient to de- 

 crease the amount of sugar in the grapes to such an extent that 

 their value for wine is very greatly lessened. Many growers 

 did not at first realize the seriousness of this disease. In some 

 vineyards it even obtained a firm foothold without being noticed, 

 for the portions of the fungus which are on the exterior of the 

 leaves are borne on the under side. When, however, it became 

 established in a certain district, all doubts regarding its serious- 

 ness vanished, and the vineyardists found themselves confronted 

 by a disease which not only threatened to destroy their vines, 

 but which gave unmistakable proof of its power to do so. 



The remedies in general use for controlling the European 

 surface mildew (Oidium Tucker i) proved to be of little value 

 against this new foe. Spraying with milk of lime was recom- 

 mended and very thoroughly tried, but it did not give such 

 good results in France as were reported from Italy. The milk 

 of lime was used with good results against the oidium of the 

 grape by Professor Keller even before 1852. l In 1881 Professor 

 Garovaglio, director of the cryptogamic laboratory at Pavie, 

 used it with fairly good success against the peronospora, but his 

 statement of this work, although apparently of the greatest im- 

 portance, received no attention from Italian vineyardists. It 

 was not until 1883, when the work of the agricultural school at 

 Conegliano, Italy, became known, that the remedy was generally 

 adopted. Many growers in northern Italy, especially the Bel- 

 lussi Brothers, near Conegliano, were particularly successful, 

 and so much confidence was placed in their method of control- 

 ling the mildew that the minister of agriculture, in a circular 

 published in 1885 recommended its general adoption. During 

 1 Cerlettie Cuboni, Annali di Agricoltura, 18S6, 20. 



