41 



more than varietal — i. c, such as miglit be induced by the long-con- 

 tinued use of different substrata. This is true even if the fungus can 

 not be transmitted from one liost to another, and a suflicieut number 

 of experiments have not yet been made to enable one to declare with- 

 out reserve that this never takes [)lace under any circumstances — e. g., 

 with help of some other fungus, or under peculiar conditions of environ- 

 ment not yet discovered. At present, therefore, nothing remains but 

 to consider the fungus as one species and to record the forms on the 

 other host plants as varieties. Possibly it may finally turn out that 

 they do not deserve even this rank, but the writer does not now feel 

 justified in giving tliem any less. 



VITALITY. 



From its vitality under adverse conditions, its ability to live in the 

 dung heap and in the soil, and the ease with which it may be cultivated 

 on all sorts of artificial media in the laboratory, this fungus must be 

 regarded as a serious eneuiy to agriculture. While we know it only on 

 the i)lants mentioned, it is probably capable of attacking other species, 

 and ought certainly to be expected and looked for on other hosts.^ 



The length of time the fungus will remain alive in the earth is 

 remarkable, and adds greatly to the difficulty of combating it. Why it 

 should ever disappear, any more than a bad weed, when once estab- 

 lished in a cultivated soil, is not dear. It should certainly be regarded 

 as a weed, and one the eradication of which presents unusual difficulties. 

 In extensive field culture it has been found unsafe to plant lands which 

 have once suffered from it until after a lapse of several years— five to 

 seven, according to south Georgia melon growers, and certainly more 

 than three, as shown by a 7-acre field test in South Carolina, which 

 came under my own observation in 1895. Only 3 wagonloads of melons 

 were obtained from the whole field. 



The melon fungus has lived a year in the dried-out soil of pots used 

 in my greenhouse experiments, and a very similar fungus parasitic on 

 cabbage remained alive in dry soil three and one-half years.^ The 



1 Since this was written Mr. Orton has found the fnngns on James Island, South 

 Carolina, in a weed, the Cassia ohtusifolia L. Not many plants were attacked, hut 

 the external symiitoms were identical with those on the cotton and cowpea, while 

 the walls of the vessels of stem and root were stained hrowu and the lumeu was 

 filled frequently with mycelium, abstricting the typical microconidia, and sometimes 

 browned, as in cotton. 



-The writer has just concluded an experiment with a similar looking and acting 

 cabbage Fusarium. In parts of New York, Virginia, and Maryland this fungus has 

 troubled the market gardeuers, in some cases renderiug impossible the profitable 

 culture of cabbages on large and fertile fields — e. g., a field in New York. which for- 

 merly yielded from 90,000 to 95,000 heads of marketable cabbage for each 100,000 

 plants set out, can now l>e depended upon for only about 30,000 heads; on a lield in 

 Maryland which formerly yielded good croi)s, the cabbages were so badly affected 

 this year that the ground was replowed and planted to other crops in the middle of 

 the season. The symptoms in the cabbagi- are slow growth, refusal of the heads to 

 form, a sickly color, aud the premature shedding of the lower leaves, from the axils 



