Family Compositae 139 



siderable damage. Grayish irregular spots appear 

 on the leaves and often become so numerous as to 

 involve the entire surface, in which case the affected 

 leaf becomes brown and eventually dies. 



DISEASE OF ARTICHOKE, GLOBE {Cynara 

 scolymUs) 



The globe artichoke is little' cultivated and very 

 little known to the people of the United States. In 

 Europe and especially in Asia this delicious tanick 

 crop is more extensively grown. Globe artichoke is, 

 as far as known, attacked by few diseases. 



Leaf Spot] 



Caused by Cercospora obscura H. and W. 



Heald and Wolf' found this disease on the globe 

 artichoke in Beeville, Texas. The disease is char- 

 acterized by minute gray spots on the upper surface 

 of the leaf. The gray color is brought about by the 

 appearance of the tufts of conidiophores and conidia 

 on the surface of the spots. 



The conidiophores of the fungus are non-septate, 

 borne in groups of four to seven, and hyaline at the 

 tips. The conidia are cylindrical in shape, straight 

 or curved. 



Control. None of the diseases of the Jerusalem or 

 the globe artichoke are ever serious enough to attract 

 attention. However, where these crops are grown 



' Heald, F. D., and Wolf, P. A., Mycologia, 3 : 5-22, 1911. 



