CHAPTER XIV 



CATALPA DISEASES 



The two species of catalpa grow naturally in southeastern 

 and central United States. Both species are used &s orna- 

 mentals. A few leaf -spot diseases cause some damage to 

 catalpa according to the locality and the season (see page 30). 

 Otherwise the tree is not subject to serious diseases, except 

 in plantations where the yellow wood-rot is destructive. The 

 predisposing of the catalpa to this wood-rot, by planting the 

 trees closely, illustrates the importance of branch wounds 

 as infection courts for the heartwood-rotting fungi. The 

 rapidity with which this rot progresses in the living tree com- 

 pared with the well-known durability of catalpa timber points 

 to the existen,ce of some condition within the tree which favors 

 the development of the causal fungus. 



Yellowish Wood-Rot 



Caused by Polysticlus versicolor Fries 



This destructive heartwood-rot of the hardy catalpa may 

 be found wherever the trees grow. The disease is not common 

 in trees growing in the open. In close stands, however, the 

 limbs are killed by shading and after they break away, holes 

 are left which soon become infected by the spores of the fungus 

 causing this rot. The causal fungus is a very common sapro- 

 phyte, which grows everywhere on the wood of deciduous 

 trees. It may often occur as a semi-parasite in the bark and 



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