144 



of copper sulphate and lime, /. e. with a considerable excess of 

 lime. So far as I have seen, if Bordeaux mixture is made (like 

 that made from the Woburn Bordeaux Paste) with practically no 

 excess of lime,* it either does not adhere so well to the parts 

 sprayed, or more quickly washes off under the action of rain or 

 dew, and consequently does not protect the plant for long from 

 fungus pests. In 1908 I compared the adhesive power of Bordeaux 

 mixture made with " milk-of-lime," /. e., a mixture containing an 

 excess of lime, with that of the mixture made with "lime-water," 

 /. e., a mixture containing no excess of lime. The two mixtures 

 were tested in potato spraying on a fairly large scale. It was 

 found that the latter mixture was washed off comparatively soon 

 by the rain, and in consequence of this the " blight " ( Phptophthora 

 infestans) was not kept in check to anythmg like the same extent 

 as where the haulm had been sprayed with the Bordeaux mixture 

 made with " milk-of-lime." Experiments were made during icx)9 

 with Bordeaux mixture made from the Woburn Bordeaux paste, 

 both on apple trees and on potato haulm. In both cases all 

 visible traces of the spray had disappeared several weeks before 

 the spray from Bordeaux mixture made with " milk-of-lime " had 

 become washed off. In the case of apple fotiage, the " scab " 

 fungus began to grow on the leaves, showing that there was a 

 complete absence there of any fungicide. The same experience 

 has been reported to me by a fruit-grower in East Kent, who for 

 several seasons past has been successful in keeping a large acreage 

 of appeals practically free from " scab " by spraying with home- 

 Jiiade Bordeaux mixture, although previously this paste had been 

 very prevalent. This grower writes as follows : " I experimented 

 with the Bordeaux paste and used it in exactly the same way as 

 that which I made myself and found it practically worthless. 

 Those trees which were sprayed with it (three times) were covered 

 with apple " scab," while those sprayed with the home-made 

 mixture were kept practically free." On the other hand, a fruit- 

 grower in Sussex tells me that the use this season of Bordeaux 

 mixture made from the Woburn paste kept his trees healthy, 

 although last season they suffered severely from "scab."* 



From my own experience I should advise the commercial 

 fruit-grower at present — until more experiments have been made— to 

 continue to make the bulk of his own Bordeaux mixture himself, 

 while using a small quantity of the Woburn Bordeaux paste 

 experimentally. 



II. The Application of Bordeaux Mixture. The best type of 

 spraying machine for spraying with Bordeaux mixture depends to 

 a large extent on such circumstances as the height of the trees 



' Bordeaux mi.Tture containing no excess of lime can be easily made by using just 

 enough lime, in the form of " lime-water," to precipitate all the copper (see Wohurn Expcr. 

 Fruit Farm, 8th Report, p. 9 (1908). 



■ Mr. Pickering (Wohuni Expt. Fruit Farm, iith Report, p, 178) says, " Reports re- 

 ceived have led to the conclusion that the paste has been about as efficient [during the 

 season 1909I as ordinary Bordeaux mixture." 



