DISEASES OF SHADE AND FOREST TREES. 107 



Some of the species of the cedar rust (Gymnosporangium) 



page 99) and the leaf curl fungi (see page 98) are also 



the cause of witches' brooms which die and are broken out 



l)v the wind storms, thus leaving irregular and unsightly 



Treatment. 



A- witches' broom is more unsightly than harmful, it may 

 be ignored or the trees may be pruned as for other defects. 



MISTLETOES. 



Mistletoes are true flowering plants which live parasitically 

 upon, many of our native trees. The common American 

 mistletoe (Pliomdendron flavescens (Pursh) ISTutt. is rare in 

 Xcw Jersey, occurring mostly on the black gum and red 

 maple. Where very abundant they are considered serious 

 enemies. It will be readily recognized that parasites of this 

 kind will naturally retard and stunt the growth of the tree. 

 They are also the cause of unsightly swellings and some 

 of them cause witches' brooms. Their life is usually shorter 

 than that of the trees on which they live, and 

 wlif-ii they die and decay they leave cavities S'ctoi!!?* 

 which are especially favorable for the introduc- 

 tion of pathogenic fungi and other organisms of disease. 

 .Mistletoes are so rare in this State that most people will be 

 inclined to look upon them as objects of interest rather than 

 rious pests. 



Treatment. 



They can be controlled by pruning out the diseased parts 

 and painting the wounds with white lead or coal tar. 



