THE MONTHLY BULLETIN. 415 



If a plant were pulled up when the tubers were mature and an area cut 

 ofit' near the stem, a dark ring was observed on the cut surface. This 

 disease was of a fungous nature. The effect of this fungus was, pri- 

 marily, to produce a wilt. The fungus apparently gained entrance 

 through the roots and from them spread to the stem and leaves. The 

 entrance to the tuber was made, therefore, through the stems on which 

 the tubers Avere borne. The weakened condition of the plant, due to the 

 attack of this disease, made the tuber more susceptible to the attack of 

 other fungi which caused decay. In controlling this disease it was 

 important to get clean seed. It appeared that dry soil was more 

 favora])le for the spread of the organism. 



Anotiier disease prevalent was the potato .scab. The rough scabs 

 grew on the surface of the tul^ers and on the vines. The fungus gave 

 rise to a scabby, corky growth. There was no considerable amount of 

 decay following scab. The disease was a curious one, with regard to 

 acidity and alkalinity of the soil. Alkaline soils favored the growth of 

 the fungus. Clean seed was important in controlling and preventing 

 this disease. 



The Rhizoetonia was another fungous disease somewhat like those 

 previously mentioned. It lived in the soil. We were not entirely 

 familiar with its soil life. The potatoes that developed were not injured 

 to any appreciable extent. The fungus began to grow on the young, 

 tender .stalks, and thus killed or prevented the growth of the young 

 potato. I'lants infested Avith this disease, instead of forming tubers 

 underground, sometimes formed small tubei's in the axils of the leaves. 

 This fungus attacked many other plants besides the potato. In Cuba 

 tobacco seed beds, if moist conditions were favorable, would be ruined 

 by damping off. The plants affected by the disease presented the 

 appearance of having been crushed and soon after the mildew-like 

 growth of the mycelium would be seen, from which the spores were 

 produced. The spores were almost never produced in our potato fields, 

 the fungus probably being carried in vegetable matter. In the control 

 of this disease general sanitary precautions were important. 



The leak disease resulted from infection of wounds in the potato. As 

 can be seen from the name, the leak fungus caused a watery-like condi- 

 tion of part of the potato, which leaked out. The remedy for this 

 disease was care in handling the potato in harvesting. Such a wound 

 as a tule wound might give entrance to the spores of this fungus. 



The potato eelworm was another problem. This was a nematode. 

 Root knot occurring on many other plants was due to the same organism. 

 In preventing soil infestation by the eelworm it was important that 

 seed free from this pest be planted. We might expect more trouble in 

 the future from this nematode. 



Late blight of the potato, while it occurred in California, did not do 

 any appreciable damage, but in the Eastern States and Europe potato 

 growers had much trouble with this fungus, and from all reports this 

 disease was worse than all the others put together. It was controlled 

 by spraying. 



Dr. Orton's Address. 



Dr. Orton, of the Bureau of Plant Industry, United States Depart- 

 ment of Agriculture, emphasized the importance of clean seed, removal 

 of the culls, rotation of crops, and better study of agricultural methods 



