APPENDIX. 417 



resistant, and buried in the bark of the twigs it is generally admitted that 

 the disease may tlius pass the winter, producing the following spring a crop 

 of spores to reinfect the young branches and leaves, as well as the fruit 

 clusters. It is also believed that the fungus may pass the winter in the dis- 

 eased fruit and leaves. In Germany a winter stage of the fungus has been 

 found belonging to the genus Venturia. 



In artificial cultures on bean stems and other nutrient media, I have 

 grown for some time the fungi of apple and pear scab. These cultures hav^ 

 yet given no indication of this other fruiting stage, or winter form of the 

 fungus. 



(c) Does pear scab differ from apple scab / — It is well known that pear scab 

 differs from apple scab in some particulars; but some have claimed that 

 these differences are so small as not to denote that the fungi are distinct. 

 However, it is of considerable practical importance to know that some 

 recent work tends to show that these fungi ai^e distinct species ; hence, if 

 this is true, pear scab cannot spread to the apple, and there cause apple 

 scab, or vice versa. 



VARIETIES AFFECTED. 



Scab affects to a greater or less extent a number of the varieties com- 

 monly grown in New York. The data upon this subject are limited, but it 

 is generally reported that Le Conte, Kieffer, and Bartlett are less attacked 

 than such varieties as Anjou, Lawrence, Duchess, Clairgeau, Sheldon. 

 Seckel, Summer Doyenne, Flemish Beauty, and Jones. On Seckel, Flemish 

 Beauty, and Summer Doyenne, I have found it very abundant during the 

 past two years. In a list of about twenty-four varieties given by Beach in 

 Bulletin 84, of the New York State Experiment Station, we find none other 

 than the three mentioned included among those only slightly attacked. 



REMEDIES. 



Since we may assume that this fungus lives over wanter in the young 

 branches or diseased fruit, it is quite evident that there is all the more 

 reason for beginning any Avork of prevention at the earliest time expedient. 

 Fairchild found that before the flower buds open the young scab spots may 

 appear upon them. It is very important to prevent the early establishment 

 of the disease : for once having secured a foothold, spores are rapidly pro- 

 duced, and dissemination is very rapid during seasons favorable for the 

 disease. 



For the prevention of this fungus many experiments have been made at 

 various stations with the dift'erent fungicides. During the past few years 

 special attention has been given to pear scab at the Geneva Station in New 

 York. The final results are not at all discordant with those of other sta- 

 tions, and recommendations are made somewhat accordingly. Spray three 

 times with bordeaux mixture of the fifty-gallon strength. The first spray- 

 ing should be made before blossoming, but after the fruit buds burst : the 

 second, immediately after the petals fall, and the third, ?^bout two weeks 

 after the second. 



