Damping Off. 339 



fungus, and in twenty-four hours a profuse growth of an Artotro- 

 gus, supposed to be the common A, deharyanus was developed. 

 The speoies was at that time not accurately determined, and at the 

 present writing there is none of the disease in the houses. The 

 trouble is invited by keeping the soil around the stems in a too wet 

 condition, just such conditions as favor the development of the seed- 

 ling fungus. It is quite possible that another fungus, to be de- 

 scribed in a later paragraph, may also have something to do with 

 the etiology of the trouble. 



Da^iping Off by a Sterile Fungus. 



Much of the trouble in the nature of damping off both in the 

 forcing house and in the fields is caused by a fungus which has been 

 under study at several different times during the last three years, 

 but up to the present time has refused all the encouragement 

 which it has been possible from present experience to offer it, with 

 the hope of inducing it to develop some characteristic fruiting or- 

 gans in order that its real nature and affinities might thus be made 

 known. There are quite characteristic features of the mycelium 

 and of certain sclerotoid bodies developed on the mycelium, and 

 which, with a little care, serve to distinguish it from other known 

 fungi. 



I first observed it while studying the diseases of the cotton plant, 

 (See Bull. Ala. Agr. Exp, Station, Dec. 1892.) In the cotton- 

 growing States it is a very frequent parasite on young cotton plants^ 

 and produces a very large percentage, so far as my observation has 

 gone, of what is known as " sore shin " in that section. The trouble 

 is caused by the fungus growing first in the superficial tissues of the 

 stem near the ground and disintegrating them before it passes to the 

 deeper tissues ; in other words the fungus never seems to penetrate 

 far in the living tissues, but " kills as it goes," and the tissues be- 

 come brown, depressed and present the appearance of the plant 

 having a deep and ugly ulcer at the surface of the ground. The 

 fungus does not spread into the tissues either above or below the 

 ulcer to any extent, but literally eats away at that point until it has 

 severed the stem at the affected place or the plant has recovered 

 from its effects. The plants do not seem to suffer seriously from 

 the disease until the woody portion containing the vascular bundles 

 is nearly or quite eaten away. 



