340 



BULLETIN 226. 



of the scab on the apple. Scab did considerable damage to the foliage in 

 unsprayed orchards in 1904. 



Leaf spots caused by other diseases. Fig. 84 shows the spots caused 

 by a different fungus, probably Phyllosticta. These spots are of a reddish- 

 brown color. They do not blister the leaf. This fungus did little 

 damage in 1903, but in the wet season of 1904 it caused much damage 

 to the leaves. Spraying seems to have had little or no effect in checking 

 this disease. 



The so-called " yellow leaf " that caused the leaves to fall during July 

 and August was partly due to this trouble and partly due to wet 

 soil. Many orchards that are ordi- 

 narily well drained were wet this 

 year. (See Fig. 74.) Those that 

 are ordinarily too wet were very 

 bad in 1904. The leaf spot was 

 generally much worse in the poorly 

 drained orchards. In some orchards 

 the scab on the leaf and the mites 

 also caused leaves to fall. 



Leaf-blister mite. Fig. 85 shows 

 the under side of a leaf infested 

 with the blister mite. This had not 

 been reported as occurring on the 

 apple until it was found during the 

 orchard survey in Wayne county. 

 Specimens were sent to Professor 

 Slingerland, who wrote as follows 



FIG. 85. Under side of leaf, showing leaf concerning them : " The pear-leaf- 



blisters caused by mites. ... 



blister mite is now a well-known 



pest in many sections of the country, but never before until last summer 

 had we seen or heard of a similar pest in apple-leaves. Scattered through 

 central New York there were many apple-trees with many of their leaves 

 showing the corky blisters characteristic of these mites. We have not 

 yet made a careful study of the mites to determine if they are the same 

 as the pear species. The blisters in the apple-leaves differ slightly from 

 those in pear, but this may be due to the different food-plants."* These 

 mites were found in 53 orchards in 1903 and were found in many orchards 



*Bulletin 46. Division of Entomology, U. S. Department of Agriculture. 



