450 EXPERIMENT STATION RECORD. 



Some important pear diseases, B. M. Duggae {New York Cornell 

 Sta. Bui. 145, pp. 596-627j figs. 16, dgm. 1). — Notes are given on pear- 

 leaf spot, leaf blight, pear scab, aud pear blight. 



The leaf spot due to Septoria piricola is said to be widely distributed 

 throughout the State, and while the fungus is one of the most important 

 from an economic standpoint, it seems to have been almost wholly over- 

 looked or neglected. Perhaps one of the earliest mentions of this disease 

 was that by (i. F. Atkinson. 1 It is usually confused with the ordinary 

 leaf blight, due to Entomosporium maculatum. The leaf spot, as it 

 appears on the green leaves, is usually larger, more'sharply defined, and 

 somewhat angular, being roughly limited by the subdivisions of the 

 venation. The center of the spots is grayish-white, dotted with minute 

 pycnidia. Surrounding this is a brown zone, which frequently shades 

 off into a purplish color. The cluster of fruiting 1 bodies in the center 

 of the spot is a very evident characteristic. 



The author reports the disease as probably occurring all over the 

 State of New York wherever pears are raised, and also in Pennsylvania, 

 Maryland, Virginia, Alabama, and elsewhere. His investigations seem 

 to indicate that different varieties are subject to the disease in varying 

 degree. Anjou, Seckel, Bosc, Summer Doyenne, and Bartlett are quite 

 subject; Louise Bonne, Clairgeau, Clapp Favorite, Flemish Beauty, 

 and others to a less extent; Duchess very slightly, and Kieffer and 

 Winter Nellis are apparently free from it. 



An experiment was conducted in which Bordeaux mixture, ammonia- 

 cal copper carbonate, and potassium sulphid solution were sprayed on 

 Bartlett and Seckel trees for the prevention of leaf spots. Three 

 sprayings of Bordeaux mixture gave almost complete protection against 

 the disease. The occurrence of leaf spot on nursery stock has also 

 been investigated, and some attempts have been made to prevent injury. 

 In this case, as in the trial in the orchard, Bordeaux mixture gave the 

 best results. The microscopic characters of the fungus are given at 

 some length. The author states that the fungus is evidently to be 

 referred to Septoria piricola. He has compared American specimens 

 with specimens from Europe and found that they agree in almost every 

 particular. 



The leaf blight of pears has also been studied in connection with the 

 leaf spot, and the author states that the spots of the leaf blight are 

 usually smaller than those of the leaf spot, are more nearly circular, 

 and not so clearly defined on the under surface. On the fruit the spots 

 of leaf blight are red at first, but soon become darker. The drying of 

 the epidermal cells may cause cracking to a considerable extent, as in 

 the case of the pear scab. The leaf-spot fungus in no case attacks the 

 fruit. The microscopic characters, distribution, and remedies of leaf 

 blight are given. 



1 Garden and Forest, 10 (1897), p. 373. 



