RECENT STUDIES ON SCLEROTIUM ROLFSII SACC. 



By J. J. Taubenhaus 



Chief of Division of Plant Pathology and Physiology, Texas Agricultural Experiment 



Station 



ECONOMIC IMPORTANCE OF THE FUNGUS 



As a parasite ScleroHum rolfsii Sacc. is of the same economic importance 

 to the South as Sclerotinia lihertiana Fck. is to some of the more northern 

 States. Rolfs {12, 13, 14Y, in Florida, and Earle (j), in Alabama, found 

 it to be serious on tomatoes. In I^ouisiana, Edgerton and Moreland (j, 

 p. 19) also found it upon tomatoes. Fulton (4, p. j), states that it often 

 ruins the pepper crop in Louisiana. Wolf (2, p. 142-146), in Alabama, 

 and McClintock {id), in Virginia, have fully recognized its economic 

 importance as the causal organism of a peanut trouble. Earle and 

 Rogers (2) and Wolf {21) have studied a citrus disease due to Sclerotuim 

 rolfsii, and Peltier (u) has also found it on cultivated perennials. 

 Godfrey (5) found it on wheat. In Texas, the writer obser\^ed 

 Sderotium rolfsii attacking cantaloupes, tomatoes, peppers, peanuts, 

 watermelons, young cotton seedlings, sweet potatoes, radish, cabbage, 

 young com plants, Bermuda grass, and a large number of weeds. 

 It is to be regretted that there are no definite statistical data on crop 

 losses from the attacks of this fungus. However, a conserv^ative 

 estimate might place these losses at about 5 per cent of the southern 

 crops. In Texas Sderotium rolfsii, although wddely distributed, seems 

 restricted to the sandy or sandy loam soils, the greatest damage occurring 

 in wet seasons. The writer has repeatedly failed to find it on the 

 heavy M'axy soils where Ozonium omnivorum Sh. is so prevalent. The 

 fungus is an air-loving organism, so it commonly finds an ideal environ- 

 ment in the light sandy soils. 



Sderotium rolfsii, although apparently occurring only in the South, 

 has been recently reported by Peltier {11) for the first time in Illinois. It 

 seems rather difficult to account for its sudden appearance there. Hal- 

 sted (6,7), in working with a pure culture of this fungus originally derived 

 from Florida, found considerable difficulty in obtaining positive infection 

 with plants in New Jersey. The fungus has, so far as knowTi, not been 

 found there as a field trouble. The writer had difficulty in infecting 

 healthy plants in Delaware, in 191 2, with a pure culture sent to him 

 from Alabama, It is to be remembered, too, that in Delaware S. rolfsii 

 does not occur as a field parasite. It is probable that in Illinois the 

 fungus was introduced with imported ornamentals from the South. In 



' Reference is made by number (italic) to " Literature cited," p. 37-138. 



Journal of Agricultural Research, Vol. XVIII, No. 3 



Washington, D. C. Nov. i, 1919 



so KeyN0.Tex.-4 



(127) 



