MISCELLANEOUS PAPERS. 219' 



primarily caused by the apple-scab fungus. Tlie leaves were also more 

 or less injured, but this was due partly to the action of other fungi as 

 well as the fnsicladiura. However, the latter may be considered as the 

 worst pest, and any treatment which will effectually check it will un- 

 doubtedly render the others harmless also. 



The life history of the fungus has not been well determined. Mr. 

 Fairchild, of the Division of Pathology at AVashington, writes me that 

 the Infections take place earlier in the season than was supposed ; in 

 fact, that it is probably that the disease often obtains a foothold even 

 before the petals fall from the tree. The experiments made here the 

 past season tend to contiim the statement. The application of some 

 fungicide before the buds of the apple open will probably be as valu- 

 able as any later treatments which may be given. When the fungus 

 has once penetrated the plant tissues, there can be no efiQcient reme- 

 dies for it. The fungicide should be upon the tree before the spores 

 of the fungus germinate ; and those of the apple-scab occasionally seem 

 to be growing even before the opening of the first leaf-buds. The 

 apple-scab first appears upon the fruit in the form of grayish, slightly 

 sunken spots. These generally are circular at first, but when several 

 grow together, their outline is irregular. As the spot enlarges, the 

 center becomes quite dark, even black. At the edges may be seen the 

 epidermis, or skin of the apple ; it is loosened by the disease, and 

 forms a light-colored line which plainly divides the diseased from the 

 healthy tissues. 



The codlin-moth lays its eggs early in the spring in the blossom 

 end of the apple, before the fruit has turned down. The larvte, or 

 worms, which develop from these eggs, make the apples wormy. The 

 time for fighting this pest is fortunately the same as that for the apple- 

 scab, and in this fact lies the value of a combination of insecticides and 

 fungicides. As soon as the apples hang down, the arsenite may be 

 omitted, but the use of the fungicide may still be advisable. 



The pruning and the spraying of fruit-trees "are two subjects which 

 are closely related. This is especially true in the case of the apple. 

 Moisture is favorable to the development of the apple-scab fungus. 

 When the tops of the trees consist of a tangled mass of large and 

 small branches, they are much longer in dying out than when they are 

 open. Kot only is a shelter given to fungi, but their growth is encour- 

 aged, and each tree becomes the distributing center of some disease. 

 The mischief is also aggravated by the fact that it is as difficult for any 

 remedies to gain an entrance as it is for the light and air. It is impos- 

 sible to spray such trees to advantage, even granting that the fruit 

 borne by them would warrant the expense. The head of the tree should 

 be open so that all parts may be reached easily with the spray. 



