SPRAYING THE APPLE ORCHARD. 



39 



surface, which afford the usual place of entrance for the 

 fungi. When the fungus has once gained entrance to the 

 host plant there is but little that can be done to stop its 

 further growth at that place, but it usually may be pre- 

 vented from starting at other points. This may be done by 

 killing the germinating spores before they have opportu- 

 nity to grow into the tissues of the host plant. The best 

 way to do this is to spray with Bordeaux mixture, or some 

 similar fungicide, which is therefore a preventive rather 

 than a cure. Numerous fungous diseases injure the apple, 

 but most of them are controlled by the sprayings advocated 

 below, and upon only two of them have observations as to 

 the effect of spraying been made in the past year. 



Apple Scab. — The scab is one of the worst of the fun- 



FiG. 25.— Apples affected with scab. 



gous diseases of the apple, attacking both the leaves and 

 the fruit. It appears in the spring on the young leaves as 

 velvety, olive spots. In severe cases the leaves become 

 shrivelled and distorted, and finally drop off. On the 

 fruit it produces olive-black spots, which in their later 

 stages have a narrow margin of light gray. Scabby apples 



