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THE GARDENERS' CHRONICLE OF AMERICA. 



the seed coat, or as living mycelium which invades the 

 same. The anthracnoses are a class of diseases which 

 sometimes have their starting point with diseased seed. 

 Examples of this is the anthracnose disease of the sweet 

 pea (Clomerella rufomaculans), the bean anthracnose 

 (Colletotrichum lindemuthiamum), etc. There are no 

 svmptoms to indicate the presence of these diseases, when 

 the spores of the fungi are carried on the seed coat. How- 

 ever, when carried within tlie seed as living mycelium, 

 the symptoms of the anthracnose is indicated as spots, or 

 blackish sunken areas, or as a general shriveling of the 

 seed. When these are planted they often fail to germinate. 

 Sometimes, when the infection has not advanced too far, 

 these seeds germinate with the disease following the young 

 seedlings. The latter may never attain any size and soon 



crop diseases likewise can often be traced to diseased 

 seedlings bought elsewhere. 



3. Soil Troubles. — Under soil troubles the gardener 

 has to contend with some of the most stubborn of the dis- 

 eases of plants. There are a great number of fungi in the 

 soil which are capable of producing disease in plants. 

 However, we shall only consider four of the most active 

 parasites. The type of disease which these fungi produce 

 is known as "damping off" and wilts. These fungi are 

 met with in the field, in the garden, in the hotbed or cold 

 frame, and in the greenhouse. When once introduced in 

 a soil, they are capable of retaining their activities of de- 

 struction for years. 



(a) Damping Off Fungus (Pythium de Baryanum 

 Hesse). — This fungus attacks a variety of hosts, such as 



DOWNEY MILDEW OF TOM.VTO 



LE.VF SPOT OF TOMATO. 



SOFT ROT OF SWEET POTATI 



die, or they succeed to grow and produce a dwarfed, 

 sickly plant. In either case the field or greenhouse be- 

 comes contaminated and the healthy plants subjected to 

 the attacks of the disease. 



2. Diseases which are carried on the living parts of the 

 plant. — Under this discussion we will limit ourselves to 

 a brief consideration of the diseases of the nurserv stock. 

 Nursery stock is often the means of carrying fungus dis- 

 ease from one locality to another, from one State to an- 

 other, and even from one country to another. I have often 

 seen the fire blight of the pear introduced into a pear or- 

 chard and the latter completely devastated through the im- 

 portation of a few diseased young trees, which were 

 bought to replace some missing ones. The black rot 

 canker (Sphearopsis malorum) of the apple, which is 

 characterized by a cracking of the bark, can undoubtedly 

 he carried with the young stock to the orchard. The 

 chestnut bark disease (Diaporthe parasitica) and a host 

 of other fruit and ornamental tree diseases can be carried 

 with young stock from tlie nursery to the orchard. Truck 



lettuce, cucumber, tomato seedlings, etc. "Damp- 

 ing off" attacks the seedlings a few days after germina- 

 tion. The point of attack is at or near the surface of the 

 ground. The affected seedlings fall over and collapse. 

 The damping off fungus will also attack grown-up plants 

 when planted too close, or portions of plants when these 

 touch the ground. 



(b) Drop Fungus (Schlerotinia libertiana F.). — This 

 fungus, like the one mentioned above, is a very active par- 

 asite. It is capable of producing a damping oft' disease 

 of young seedlings; also a serious disease of greenhouse 

 lettuce and other vegetable crops. The symptoms of the 

 diseases which this fungus produces are, flagging and col- 

 lapsing of the aft'ected plant. 



(c)Sleeping Sickness. — The fungi which produces this 

 class of disease are known as Fusariums. Not all of them 

 are parasites. Some Fusaria produce damping off of 

 seedlings either in the greenhouse or out of doors. (It 

 is not known whether these all belong to one and the 

 same species), while others can produce a disease on 



