CHAPTER XII 

 BUCKEYE DISEASES 



The four species of buckeye or iEsculus native in the United 

 States are not important forest-trees. The Ohio and yellow 

 buckeye grow to be large trees in the river-bottom lands in 

 the central and southern states. A closely related European 

 species, the horse-chestnut, is extensively used as an orna- 

 mental. 



Leaf-blotch is the most destructive disease affecting buckeye 

 and horse-chestnut. This disease occurs every year through- 

 out the range of the Ohio and yellow buckeye. The horse- 

 chestnut is often severely affected and defoliated in the north- 

 eastern states. A powdery mildew is also common on these 

 trees. The California buckeye is subject to a leaf-blight and 

 witches'-broom disease. The wood and roots of the buckeye 

 are rarely diseased. 



Leaf-Blotch 



Caused by Guignardia cesculi (Peck) Stewart 



Throughout central, southern and eastern United States, 

 Ohio and yellow buckeye and the horse-chestnut are commonly 

 affected by this leaf-blotch. The disease is also known in 

 southern Eiu-ope. It is probable that the disease is present to 

 some extent on the other species of buckeye. A large percentage 

 of the foliage of horse-chestnut trees in parks and along streets 

 is affected every year. In the nursery this disease interferes 

 seriously with the growing of horse-chestnut stock. Repeated 



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