54 EXPERIMENT STATIOX EECOED. 



Trichoseptoria fnictigena on quince and apple, W. Pietsch {Latidic. Jahrb., 

 47 (1014), No. 2, pp. 303-323, figs. 13). — The author, reporting a continuance of 

 previous studies (E. S. R., 29, p. 247), states that irregular flecks on quince" 

 leaves showed pycnidia and spores resembling closely those on the fruit ascribed 

 to T. fnictigena. 



Results of culture studies on sterile substrata and on living fruits are detailed. 

 The Japanese quince is apparently not attacked, but the ordinary quince is more 

 susceptible than apple. Apparently the spores survive even hard winters, the 

 period between October and March being favorable to the spread of the organism. 

 The fungus appears to be common on fruits of haw, from which it appparently 

 passes to quince, and from this to apples in storage. This suggests early gather- 

 ing of the quince crop and careful disinfection of hands, baskets, etc., before 

 handling the apples. 



The cedar rust disease of apples caused by Gymnosporang'ium juniperi- 

 virginianse, H. S. Reed and C. H. Ckabii.l (Virginia Sta. Tech. Bui. 9 (1915), 

 pp. 3-106, figs. 23). — ^A detailed account is given of the biology of the fungus 

 causing a rust on apple foliage and fruit, and the effect produced on each host 

 plant is discussed. ' The investigations on which this report is based have been 

 in progress since 1910, some data regarding control measures having been pre- 

 viously issued (E. S. R., 30, p. 450). 



In the present bulletin, accounts are given of investigations on the spring 

 development of the fungus on the cedar, its development ou apple foliage and 

 fruit, the sporophytic and gametophytic generations of the fungus, chemical 

 studies of diseased and healthy leaves, influence of the fungus on the transpira- 

 tion, photosynthesis, and respiration of apple leaves, and a summary of experi- 

 ments for the control of the rust on apple foliage. 



The authors found individual variation regarding susceptibility of cedar trees 

 to attacks of the fungus, which was also shown by varieties of apples. Of the 

 apple foliage, only young leaves are susceptible, and infection takes place only 

 in the presence of abundant moisture. The transpiration of affected apple trees 

 was found to be almost constant, whether in light or in darkness, due probably 

 to the stomata becoming unresponsive to light stimulus. Photosynthesis was 

 reduced and respiration increased in diseased leaves. Chemical analysis 

 showed a decrease in total sugars, invert sugar, and starch, and an increase of 

 sucrose in the rusted leaves. 



Discussing means of control, the authors conclude that the application of 

 fungicides has not proved to be a practical method of controlling the disease 

 when red cedar trees are present in the neighborhood of apple orchards. In 

 such cases, permanent relief can be obtained by the removal of all reil cedar 

 trees in the vicinity. 



A bibliography is appended. 



Apple leaf spot or black rot canker, P. I. Bbyce (Ann. Rpt. Quebec Soc. 

 Protec. Plants [etc.], 7 (1914-15), pp. 86-90, figs. 5).— This disease (Spharopsi-s 

 malornm ) has been noted at Sainte Annes in two forms, the frog-eye spots on 

 the leaves and the canker on limbs and growing or stored fruit, several varieties 

 being attacked. 



^Maintenance of the trees at full vigor is recommended as a general treatment 

 for the trees and the growing fruit. Temperatures below 40° F. reduce or pre- 

 vent black rot in stored fruit. 



Apricot gummosis and sour sap, L. H. Day (Mo. Bui. Com. Hort. Cah, 4 

 (1915). No. 7. pp. 330-332). — Observations and tests as noteil have led to the 

 view that many gumming and sour sup conditions of the apricot tree which are 

 common in the coast regions of California are caused by fungi or bacteria which 



