Dec., 1909.] 



SOME APPLE DISEASES. 



125 



Fig. 22.— Early stage of Leaf Spot. 



mer. (See Figs. 24 and 25.) Trees so robbed of their foliage 

 from year to year must eventually become greatly impaired in 

 their vigor and finally succumb to 

 a premature destruction. 



The cause of the leaf spot has 

 occasioned no little difficulty. A 

 number of fungi have been found 

 to be present in these spots as they 

 occur in other parts of the country, 

 and the work of Lewis^ has shown 

 the same condition to hold in New 

 Hampshire. The fungi which have 

 been found to predominate in the 

 spots here are Sphceropsis, Malo- 

 rum, Coniothyrium pirina, Cory- 

 neum foliicolum, Alternaria sp. 

 and one of the Tuhercularice. The 

 work of Scott and Rorer- showed 

 that the first of these is responsible 

 for the majority of spots in the 

 South and central West, and the isolation and inoculation experi 



Fig. 23.— Late stage of Leaf Spot, 

 showing growth in the size of the 

 spots. 



•Lewis, I. M. Apple-Leaf Spot, N. H. Agr. Exp. Sta., Nineteenth and Twentieth 

 Reports. 365-370, 1908. 



» Scott, W. M., and Rorer, J. B. Apple-Leaf Spot Caused by Sphooropais Malorum. 

 Bureau of Plant Industry. U. S. Department of Agr. Bull. 121. 



