278 FUNGOUS DISEASES OF PLANTS 



Control. It is of unquestionable value to keep the orchard as 

 clean as possible of apples affected with the bitter rot fungus, 

 and it is likewise important to prune out all cankered limbs. 

 Nevertheless, these precautions alone are wholly insufficient, and 

 it has recently been demonstrated that the disease may be con- 

 trolled — at least under the conditions prevailing in the eastern 

 United States — by a proper application of Bordeaux mixture. 

 Under conditions favorable for the spread of the disease, from 

 93.3 to 98.9 per cent of sound fruit has been harvested upon 

 sprayed trees, while the controls gave practically no fruit of value. 

 It is recommended to make about four applications of Bordeaux 

 mixture, although one or two additional applications may be 

 necessary. In this as in all other such work, the tree should be 

 thoroughly sprayed from a nozzle giving a mist-like application. 

 When spraying for bitter rot alone the first application may be 

 made about forty days after the petals have fallen, subsequent 

 applications being given about two weeks apart. During very wet 

 weather, however, greater frequency may be required, while in 

 cool weather the length of time may be increased. Beneficial 

 results from spraying experiments have also been obtained in the 

 central West, and it is believed that there the disease may be 

 controlled by the methods suggested. 



XLVI. ANTHRACNOSE OF SYCAMORE 

 Gnomonia Veneta (Sacc. & Speg.) Kleb. 



Edgerton, C. W. The Physiology and Development of Some Anthracnoses. 

 Bot. Gaz. 45: 367-408. pi. 11. figs. i-iy. 1908. 



Klebahn, H. Unters. uber einige Fungi imperfecti u. d. zugehorigen As- 

 comycetenformen. Jahrb. f. wiss. Bot. 41 : 515—558. 1905. 



Scribner, F. L. A Disease of the Sycamore. U. S. Dept. Agl. Rept. (1888): 

 387-389. pi. 15. 



Southworth, E. A. Gloeosporium nervisequum (Fckl.) Sacc. Journal My- 

 cology 5 : 51-52. 1889. 



Habitat relations. This fungus is parasitic upon the leaves 

 and young shoots of the sycamore or plane tree, Platanus 

 occidentalis, and it is widely distributed in Europe and America. 

 In one or more stages the fungus also appears to produce spots 

 upon the leaves of several species of oak, being reported upon 

 Qucrcus alba, Qicercus velutina, and Quercus coccinea. Upon 



