New York Agricultural Experiment Station. 445 



the disease and at these places the growth is checked. Some- 

 times the fruit becomes cracked as it does when attacked by the 

 «cab. This disease appears to be more severe in states south of 

 New York and in regions near the Atlantic coast than it is in the 

 interior of the State, where it causes little damage except as a 

 nursery disease. 



Treatment. — The treatment advocated for pear scab is also 

 recommended for this disease when it appears in the orchard. 



LEAF SPOT. 



{Septoria piricola Desm.) 



Description.— This disease may be readily distinguished from 

 the one last described if the two are carefully compared. The 

 leaf spot when fully developed has a somewhat angular outline 

 and whitish center in which appear small black specks, the bodies 

 in which the spores of the fungus are borne. 



Treatment. — The only experiments in treating this disease 

 which have come to our notice are those by Duggar^^ who advo- 

 cates similar treatment to that recommended against leaf-blight. 



SCAB. 



(Venturia pirina Aderh.^^) 

 Description.- — This disease is caused by a fungus very similar, 

 both in appearance and in the injury which it does to leaves and 

 fruit, to the apple scab fungus. It robs the leaves of the nour- 

 ishment which they are preparing for themselves and for the 

 growth of the tree and fruit ; it spots the fruit and in very severe 

 attacks causes it to become one sided, distorted or cracked. 

 While it does not kill the trees or branches as the blight may do, 

 still it is l)elieved that no disease, year after year, causes so great 

 loss in pear orchards in jSTew York State as does the scab. Some 

 varieties appear to be comparatively exempt from its attacks while 



■lODugpjar, B. M. Cornell Univ., Ap;r. Exp. Sta. Bui. 145: G02-604. 

 41 This is the ascosporic stage of Fusicladium pirinum (Lib.), Fekl. 



