BOUILLIE BORDELAISE. 259 



laise an excellent method for preventing this disease. Their experi- 

 ments in the Bellefontaine Nursery, near Nancy, gave very decisive 

 results. Two treatments with bouillie bordelaise on two to three- 

 year-old plants, the first beginning in June, when the needles are half 

 formed, the second a month later, when they are fully developed, 

 assured the complete immunity of the young plants, whilst 80 per 

 cent of the untreated succumbed to the disease. Beck and Oster- 

 held tried this treatment on a larger scale, and as far back as 1889 

 this process entered into the forestry practice of Bavaria. Von 

 Tubeuf likewis- controlled the efficiency of cupric preparations on an 

 experimental field at Dahlem. His experiments show that bouillie 

 bordelaise produces more effect in August than in June or September, 

 and that it was superior to other cupric preparations. Bouillie borde- 

 laise cannot destroy the mycelium developed in the interior of the 

 plant, but it protects the sound needles of a pine-tree already invided 

 by the disease. Young plants which still have the greater portion of 

 the leaves may be preserved if the healthy leaves are protected by 

 energetic spraying at the moment when the new shoots have reached 

 two-thirds of iheir height. The first treatment should be given in 

 June, the succeeding ones very carefully in July and August, for it is 

 at that time that the invasion is the most intense, and that the leaves 

 should be entirely protected by a layer of cupric hydrate. 



Sclerotinia Cydonia, Schell. — This disease invades quinces and 

 mummifies them. It may be overcome by spraying the tree before 

 the opening of the leaves (Soi-auer). 



Monilia frutigena, Pers. (brown rot of kernel fruits). — To prevent 

 this disease the mummified fruits, brown before the harvest, must be 

 collected in winter and carefully destroy>^d, for, as shown by G lUoway, 

 brown rot can only be overcome with difficulty by bouillie bordelaise 

 and other anticryptogamic products. Chester, by six sprayings a year 

 with a big bouillie, from 29 April to 2 July, found that the number of 

 diseased fruit was lowered from 32 per cent to 13 per cent ; but that 

 the disease cannot be entirely prevented. Montemartini likewise found 

 the bouillie inefficient. Schoyen advises against this disease spraying 

 before the opening of the buds. 



Botrytis cincrea (vine sclerotinia). — Bouillie bordelaise is gener- 

 ally regarded as inefficient against the mould of grapes in autumn. 

 Sorauer and Beauverie believe that, above all, the air should be allowed 

 to penetrate more easily around the fruits by partially stripping the 

 leaves and in cutting the shoots around the grapes, and to spray after- 

 wards. 



Use of Bouillie Bordelaise against Insects. — Cupric hydrate, 

 deposited uniformly on the green parts of a plant, protects these against 

 the attacks of insects and their larvae. Plants regularly treated by 

 bouillie bordelaise are less sought after than untreated plants. After 

 eating leaves blued by a deposit of cupric hydrate insects and their 

 larvae are poisoned and die. The contact and the presence of copper 

 are so disagreeable to them that they ofteu quit the tree after treat- 

 ment with copper hydrate. Thus the caterpillars of the Hyponomeute 

 of the apple abandon the silky gauze which serves to them as a shelter, 



