CHAPTER XXI 

 The Rusts (Uredinales) 



Few fungous diseases are more widespread in the United 

 States or more readily found in any locality than the As- 

 paragus Rust. This fungus was described in Europe in 

 1805 and had doubtless existed for ages before that time. 

 As a serious enemy it first attracted attention in the East- 

 em states in 1896. It spread westward so rapidly that in 

 1 90 1 it was very destructive in California. Since then it 

 has been generally recognized as the worst obstacle to as- 

 paragus culture. 



In a way the life history of this rust is typical of the 

 great family to which it belongs. It passes through the 

 winter in characteristic spores attached to old leaves and 

 stalks, or lying loose upon the soil surface. These are 

 called the Winter Spores or teleutospores. They are 

 stalked, double-celled spores of curious and characteristic 

 form. 



In spring these teleutospores germinate as they lie upon 

 the ground or upon the standing or fallen asparagus stalks. 

 The contents of each cell break through the cell wall and 

 run out in the form of a long tube. At the end of the 

 tube four partitions develop, so that four distinct cells are 

 formed. Then the material in each cell is sent out to form 

 a tiny secondary spore or sporidium (plural sporidid). 



These sporidia are so small and light that they are easily 

 blown about by the wind. When one of them chances to 

 alight upon the green surface of a young asparagus plant 



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