Trees and Timber 395 



much injured by this mildew. It is recognized as a flour-Hke, 

 white coating and is particularly damaging to the young nuts. 



Spraying with Bordeaux mixture or lime-sulfur before the 

 fungus appears is effective. Burning of infested fall refuse 

 is also helpful. 



Anthracnose (Glomerella cingulata, Glceosporium) . — Large, 

 light brown to reddish blotches occur on the leaves and cause 

 them to fall. The nut hulls bear irregular, sunken, black 

 blotches which may extend to the whole surface, and which 

 eventually bear numerous pink acervuli. Many nuts fall 

 prematurely. 



All infested refuse should be burned; a dormant spray ap- 

 plied, another spraying given just after the buds open, and 

 if need be, one to three additional sprayings later. 



Rosette. ^^^' ^^^ — From 10 to 20 per cent of the trees in 

 the Southeast are affected. The leaves at the branch ends 

 are first yellow-mottletl, then die. Later the twigs die back 

 and the trees are seriously weakened. No parasite is present; 

 the disease seems to result from deficiency of humus, footl 

 material, and moisture, and may largely be avoided by 

 use of legumes, and by plowing under green cover crops. 



Die-back (Botryosphceria berengeriana de Not.). — -Young 

 twigs die and their surfaces bear numerous black perithecia. 

 Dead wood should be pruned out and burned. Pink-mold 

 (Cephalothecium sp.) affects the hulls, nut, and the embryo. 

 It frequently follows scab. Brown leaf-spot (Cercosporafusca 

 (H. & W.) Rand.), Nursery-blight (PhyUosticta canjce Pk.), a 

 kernel-spot (Coniothyrium) and Mistletoe do some damage. 

 Pollen-blight {Microstroma juglandis (Ber.) Sacc. var. robus- 

 tum Hig.) presents an interesting case of a fungus parasitic 

 in the anthers. 



PINE 



Blister-rust ^^^' ^-° {Cronartium ribicola F. deW., Perider- 

 mium) . — This rust which has done much damage in north- 

 ern Europe on the 5-leaved or white pines, of which there 

 are some eighteen species, entered the United States in 



