15 



poisonous, and the American species of the genus are naturall\- 

 under suspicion, though few of them ha\-e been actual 1>- tested. 



Marshall A. Howe 

 Secretary pro tern 



Meeting of December 13, 192 1 



The scientific program of the evening consisted of an illustrated 

 lecture on "Disease Resistance in Plants" by Professor L. R. 

 Jones of the University of Wisconsin. 



The speaker described studies on cabbage yellows caused by 

 the soil parasite Fusarium conglutinans. A practical outcome 

 has been the development through repeated selection of Fusar- 

 ium-resistant strains of cabbages of several leading varieties, 

 justifying the conclusion that resistant strains may be secured 

 from any of the standard commercial varieties as may be neces- 

 sary to meet regional needs. Of one of these, "Wisconsin All 

 Seasons," some 5000 pounds of seed, sufficient to plant upwards 

 of 25,000 acres, has been grown this year in a cooperati\"e re- 

 lation with the Bureau of Plant Industry and is being distri- 

 buted by the National Kraut Packers' Association. 



Similar results with other crop diseases illustrate the practical 

 significance of disease resistance such as Orton's earlier work 

 with cotton and cowpea, Bolley's wilt-resistant flax, Johnson's 

 rootrot-resistant tobacco, and the recent results with disease- 

 resistant tomatoes and beans. The fundamental problems 

 forced upon the attention of phytopathologists concern the cause 

 of such relative resistance or susceptibility and the influences 

 of environment upon predisposition or disease development. 

 Both aspects present complex problems, fundamentally physio- 

 logical, and the results of the Wisconsin studies to date indicate 

 an advantage in carrying them on in coordination. Chief 

 attention thus far has been directed to examples of soil parasites. 

 No single or simple explanation holds for disease resistance 

 with these different t}'pes. In certain cases chemical contents 

 may be the basis of resistance, in others the structure or com- 

 position of cell membranes. In either case environmental factors 

 may influence the development of disease-resistant characters. 

 Chief among these, as influencing metabolism, are temperature, 

 moisture, light, and soil composition. JNIost attention has thus 



