DISEASES OF FRUIT TREES. 29 



lack the purple coloration, and the leaves show more or less chlorosis, 

 but only bacteria were found in the dead spots. The diseased tissue 

 frequently drops out, leaving perforations with dead marginal tissue. 

 Korer (-13) has recently shown that the bacterium on the peach is 

 probabl}'' identical with the one on the fruit and leaves of the plum, 

 and we have collected the bacterial spots of both hosts from adjacent 

 trees. 



Specimens collected : San Antonio, lo65, 1399 ; Kerrville, 1.592 ; Beeville, 1863 ; 

 Elgin, 1888 ; Uvalde, 1933 ; San Marcos, 2101 ; Nursery, 2553 ; Gonzales, 2671. 



Twig-blight. — In one locality peach trees were badly blighted, but 

 no indication of die-back was observed. The dead twigs and branches 

 showed an abundance of erumpent pustules which we have referred 

 to Fusarium, sarcochroiwi (Desm.) Sacc. It is not probable that 

 this fung-us was responsible for the disease. 



Specimen collected : Falfurrias, 2456. 



PEAR. 



Bitter-rot canker {Glomenlla rufomaculans (B.) Spaul. and Von 

 Schr.). — The cankers caused by this fungus on the pear {Pyrus com- 

 munis L.) have been found in both young and old orchards, and the 

 disease is responsible for a considerable amount of injury. The 

 specimens collected represent rather young twigs, and the cankers 

 show as circular, elliptical, or irregular areas, 1 to 3 cm. long, or 

 they may girdle the twig. In the young stages of development the 

 bark is yellowish brown and slightly tumid and at length cracks 

 away around the margin of the spot, leaving the dead bark more or 

 less isolated. As the spots become older, more or less irregular rup- 

 tures are formed; these ruptures are frequently concentrically dis- 

 posed, while the whole spot becomes somewhat sunken. Only the 

 conidial stage of the fungus was found. 



Specimens collected: Kerrville, 1599; Nursery, 2570; Gonzales, 2666; Fla- 

 tonia, 2714. 



Black-rot {Sphaer'opsis mcdorum Pk.). — This disease has been ob- 

 served to cause the characteristic cankers on the branches and the 

 rotting of the fruit. 



Specimens collected: Boerne. 1650; Austin, 2219; Georgetown. 2399 (a ) ; 

 Nursery. 2572; Stockdale, 2629; Hallettsville, 2786. 



Crown-gall {Bacterium tumefadens Erw. Sm. and Townsend). — 

 Collected in an orchard 6 or 8 years old, where about 75 per cent 

 of the trees were dead. 



Specimen collected : Llano, 1771. 



Fly-speck {Le ptothynum carpophilumVQ.?,^.) . — Minute black specks 

 appear on the fruit, rendering it unattractive. 

 Specimens collected: Cuero, 2599; Hallettsville, 2794. 

 226 



