JUNIPER DISEASES 



195 



tivated fruits but also many valued ornamentals, much damage 

 is caused by defoliation when infection is heavy. 



Control. 



The control of these fungi is simple if one or the other of the 

 alternate hosts is eliminated. Although cases have been noted 

 in which a sepa- 

 ration of one to 

 several miles did 

 not totally pre- 

 vent the exchange 

 of spores, a dis- 

 tance of one mile 

 between the two 

 required kinds of 

 trees reduces the 

 amount of infec- 

 tion to a mini- 

 mum. Spraying 

 either the conifer 

 or pomaceous 

 host has not been 

 successful. In 

 some states where 

 junipers are a 

 menace to or- 

 chards because of 

 the rusts, laws are 



Fig. 30. — Cedar-apple fungus on haw leaf. 



in force requiring the destruction of all specimens within 

 one mile of orchards. 



Reference 



Kern, Frank Dunn. A biologic and taxonomic study of the genus 

 Gymnosporanguim. Bui. N. Y. Bot. Gard. 7 : 391^83, pis. 151- 

 161, figs. 1-36. 1911. 



