igo6.] Heart Rot of Beet, Mangold and Swede. 597 



and dry, a second form of fungus fruit appears on the bleached 

 patches. 



Some time after the leaves have been infected the mycelium 

 of the fungus passes into the crown of the root and thence 

 gradually extends downwards, its progress being clearly indi- 



V * \ f ■ ' -*? 



Yellow Globe Mangold, Showing Heart Rot. 



cated by a darkening of the tissues. Finally the entire root is 

 reduced to a blackish, decayed mass. 



If a portion of a diseased root, which is crowded with the 

 mycelium of the fungus, is kept until the following season, it 

 undergoes no change until about midsummer, when its surface 



