Apple. 241 



no means uncommon in the northern states, and appears to 

 be particularly destructive to the earlier varieties. Early 

 Harvest, Sweet Bough, and others are very subject to the dis- 

 ease. Any part of the apple may be first attacked, and when 

 the fungus has once gained a foothold it spreads very rapidly. 

 The older portion, or the part first attacked, soon bears small 

 black pimples, and it is said that the tissue beneath them has 

 an exceedingly bitter taste, which has given the disease its 

 name. 



Treatment. Carman 1 recommends the use of Bordeaux mix- 

 ture for preventing the development of the disease. He obtained 

 the greatest benefit from applications made as follows : First, 

 before the leaves expanded; second, soon after the apples had 

 set ; third, about fourteen days later ; fourth, four weeks after 

 the preceding. In this manner " thirty-one and one-sixth per 

 cent of the whole number of apples borne by the sprayed tree 

 during the season were saved from the rot." 



The disease has also been successfully treated by the use of 

 the sulphide of potassium. The ammoiriacal carbonate of 

 copper gave similar results. These last experiments are inter- 

 esting from the fact that the first application was not made till 

 about the middle of August. Earlier applications are, however, 

 advisable. 



Black Rot (Sphceropsis malorum, Berk.). Description. The 

 external characters of this disease are practically identical with 

 those of the Bitter Rot. The remedies to be used are also the 

 same. 



Brown Rot. See under CHERRY. 



Powdery Mildew (Podosphcera Oxycanthce, DeBary). Descrip- 

 tion. This fungus attacks the foliage of young apple seedlings 

 very soon after the unfolding of the leaves, and continues 

 its growth throughout the summer, very much weakening the 

 plants, and making them unfit for budding purposes. The dis- 

 ease is especially serious in the southern states. The affected 

 leaves have a grayish appearance which is caused by a powdery 

 substance. This gray powder consists of the parts of the fungus 

 which project beyond the leaf tissue. The leaf soon dries and 

 is rendered worthless. 



Treatment. The trouble has been successfully controlled by 



1 Gorman, Ky, Agric. Exp. Sta. 1893, Bull. 44, 5. 

 E 



