256 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



which may be afterwards sown around the trees. There are no 

 vexatious consequences to be feared (Frank and Weiss). Winter 

 treatment, however well done, does not exclude the different summer 

 treatments required to prevent this disease entirely. Physiologists 

 who have studied the question advise two spring sprayings with 

 bouillie bordelaise. Stinson by three sprayings, the first of which was 

 at the end of April, the second in the middle of May, and the third in 

 the beginning of June, got 95 per cent of healthy apples and 5 per 

 cent of spotted ones, whilst 91 per cent of the apples on the untreated 

 trees were attacked. Maxwell found seven sprayings were required 

 to cause the disease to disappear entirely. 



TABLE XLIX. — Shoiving the Effect of tlie Niimher of Sprayings with Bouillie 

 Bordelaise on the Percentage of Diseased Fears. 



Spotted Pears, 

 Per Cent. 

 Trees sprayed twice yielded .... 3-17 



„ ,, three times yielded . . . 3-57 



„ ,, seven times yielded . . . 0-00 



The bouillies recommended in the beginning by Eicaud w^ere made 

 from blue vitriol 2 per cent and lime 3 per cent.. But apples and 

 pears, particularly those which were grafted on quince-trees, were 

 too sensitive for these bouillies. The strength has been greatly re- 

 duced and equally satisfactory i-esults got with 1 per cent or even 

 0-5 per cent. Taft ascribes the corrosive action of these bouillies on 

 the leaves of apple and pear trees to the excess of lime which they 

 mostly contain ; he therefore advises absolutely neutral bouillies. 

 Muller found that whilst pure cupric hydrate produced symptoms of 

 poisoning on the plant, a 4 per cent milk of lime had no effect. He 

 observed that bouillies containing little blue vitriol (say 0-5 per cent) 

 and much lime (4 per cent) produced less burns than neutral bouillies, 

 even of 0'5 per cent. 



The object of multiple treatments is to cover not only the leaves 

 and the young shoots with bouillie bordelaise, but also the young 

 fruits. The number of sprayings evidently depends on the weather, 

 as in the trea,tment of the vine against mildew and black rot. If 

 frequent rains wash the leaves and fruit, and favour by moisture the 

 development of summer spores, sprayings should be more frequent 

 than in warm, dry weather. The first treatment is before flowering, 

 the second immediately after flowering, and the third when the fruit 

 is the size of a pea. Since 1886 Goethe, Mohr, Kruger, Caruso, 

 PegUon, Lodeman, Munson, Taft, Sturgis, Stinson, Beach, Prillieux, 

 Nijpels, Hotter, Sorauer, Muller, etc., have demonstrated the alisolute 

 efficiency of treatment with bouillie bordelaise against the scab. 

 Galloway, Fairchild, and Beach have more especially observed the 

 physiological effect produced on the tree by spraying. The ravages 

 of the Fusiciadium must not be looked at from a mere money point 

 of view, because they render the fruit unmarketable. Like all leaf 

 parasites they do damage to these organs of assimilation and injure 

 the health of the tree. The life of the plants is concentrated, on the 

 one hand, in the leaves, and on the other hand, in the roots. Between 



