FUNGI AFFECTING THE BEET 



The Beet Rust 



^ Uromyces hetoe 



In certain portions of the United States the rust of 

 sugar beets has done serious injury. It appears to have 

 originated in Europe ; and in America has been especially 

 destructive in California. Beets attacked by it become 

 dwarfed and discolored. 



Professor L. H. Pammel, of the Iowa Experiment 

 Station, has recently published the following account of 

 the life-history of this fungus : '^Ifc is characterized by 

 having three stages — the aecidio (cluster-cup) stage, the 

 uredo (red-rust) stage, and the teleuto (winter) stage. 

 The -first, or cluster-cup stage, occurs on the leaves and 

 stems of seed beets. The cluster-cups contain chains of 

 orange-yellow spores. These germinate under favorable 

 conditions, sending out a little tube, which enters the 

 leaf through its breathing pores. On the inside it devel- 

 ops the mycelium between the leaf cells, sending into 

 the cells themselves small ^suckers,' which absorb their 

 contents. After a time this mycelium produces, in cer- 

 tain places, spores of another kind called the uredo 

 spores, which are pushed out through the skin of the 

 leaf. These spores soon germinate and spread infection 

 to other plants. Late in the season still another kind 

 of spore is found. It is known as the teleuto-spore, or 

 winter-spore. These do not germinate until the follow- 

 ing spring, when a tube known as the promycelium is 

 pushed out. This tube is branched, and bears small 



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