Pip Fruits: Apples 85 



tree that has produced scabbed apples for some years, proving that the 

 disease is well established, the following is the yearly course followed 

 by the fungus: The Fusicladium or summer condition is present in 

 quantity on dead shoots and young branches. Its presence is indicated 

 by the bark becoming broken up as if gnawed by some insect. Such 

 wounds often occur at the base of the youngest shoot, or on fruit spurs, 

 and are also sometimes present on older branches. The fungus itself 

 is not very conspicuous, and appears as a blackish stain on the wood 

 under the loose bark and on the bark itself. It is very important to 

 grasp the fact that when a shoot or branch is once infected the spawn 

 or mycelium of the fungus continues to grow from year to year, or is 

 perennial in the branch and produces spores each season, and naturally 

 the number of spores produced is greater each season as the mycelium 

 spreads in the dead branch. Spores are produced on these diseased 

 branches in the spring, and are washed by rain or conveyed by other 

 means on to the young leaves, which in turn become infected, the 

 presence of the fungus on the leaves being indicated by blackish olive 

 patches of various size. If these patches are examined under a good 

 pocket lens, they will be seen to consist of numerous crowded lines 

 arranged in a dendritic manner, and radiating from the edge of the patch. 

 This appearance proves with certainty that the patch consists of the 

 fungus causing Apple scab. In due course the fungus present on the 

 leaves produces spores, which in turn are carried by some means or other 

 on to the young fruit, which in turn becomes infected. Spores are pro- 

 duced on the diseased shoots throughout the season, and these may also 

 play a part in infecting the fruit. 



From the above account it will be seen that when the branches of 

 a tree are once infected, if such branches are not removed, the disease 

 is capable of perpetuating itself from year to year without any infection 

 from outside sources. At the same time such an infected tree represents 

 a nursery of disease from which the fungus is certain to spread to ad- 

 joining trees. 



Under the circumstances rny advice is to remove all dead and decayed 

 shoots, as by so doing you remove the primary cause of the disease. 

 During the spring following the removal of the branches, spray with 

 Bordeaux mixture (see p. 49), commencing when the leaves are unfolding, 

 and again when the fruit is just set. A third spraying when the apples 

 are about the size of marbles is advisable, as some dead shoots bearing 

 spores are certain to be missed when pruning. 



It is but fair to state that iny view, as given above, is not endorsed 

 by other specialists, who consider that pruning out the dead shoots is 

 impracticable, and that by constant spraying alone the disease can be 

 kept under control. Quite true; but if the primary cause of infection 

 is not removed, the constant spraying must of necessity be repeated each 

 season, and the " russeting" of fruit and scorching of foliage are the 

 frequent results of spraying. 



