EXPERIMENT STATION REPORTS. 215 



jiotato tubers have been indexed and fields have been rogued in an at- 

 tempt to clean stock from disease and permit the development of disease- 

 free seed stock for increase by farmers. This work gives great promise 

 with certain varieties but disease elimination in some strains is very 

 difficult due to masking of symptoms. 



Black-leg investigations have concerned themselves with studies on 

 thfe severity of the disease, the effects of treatment in control and 

 agencies of dissemination. The results are now being prepared, for 

 publication. 



Cereal Disease Investigations : 



Work on cereal diseases has been carried on by the writer and has 

 consisted of tests of various fungicides for Stinking Smut control and 

 tests of disease resistance of certain varieties. The new copper dust 

 methods for seed treatment have been tested over several seasons and 

 have been used rather extensively over the state. With fairly clean 

 grain, the dusting method gives great promise. 



Far more important than the results obtained by specific treatment 

 is the evidence which several years of test have given that certain 

 hybrids of various high yielding wheats are immune to Stinking Smut. 

 In particular, hybrids with Berkeley parentage seem to be immune to 

 Stinking Smut in spite of heavy (artificial) seed contamination. 



*Seed treatment as a method of Stinking Smut control will always 

 be a readily applied method in the hands of the farmer who is willing 

 to take the trouble to prevent loss. But, if high yielding, smut-resist- 

 ant varieties can be developed, then this wasteful disease will cease to 

 be a factor at all in Michigan's wheat crop. 



Small Fruit Disease Investigations : 



In May, 1922, Mr. C. W. Bennett was transferred from full-time Col- 

 lege work to full-time Experiment Station work. His investigations 

 have confined themselves largely to raspberrj- diseases, especially dis- 

 eases of the mosaic type. He has carried out extensive rogueing tests 

 in the small fruit producing counties of the state and has demonstrated 

 the relation of aphids to disease dissemination. 



Publications : 



The following publications have been issued during the year: 



1. Kotila, J. E. Leaf Hopper Injurv to Potatoes. Mich. Sta. Tech. 

 Bui. 56, 27 pp. 



2. Kotila, J. E. Spraying for Hopper^burn. Mich. Sta. Circ. 48, 4 

 pp., July, 1922. 



3. Bennett, C. W., Loree, R. E. and C. W. Bennett The Raspberry 

 Situation in Michigan. Mich. Sta. Quart. Bui. 5:31-33, August, 

 1922. 



4. Coons, G. H. Copper dust treatment for Stinking Smut. Mich. 

 Sta. Quart. Bui. 5:8-11, Aug., 1922. 



5. Nelson, Ray. Transference, of the bean mosaic virus by Maorosi- 

 pJiiim solanifolii. Science 56:342-344, Sept. 22, 1922. 



6. Nelson, Ray. The occurrence of protozoa in plants affected with 

 mosaic and related diseases. Mich. Sta. Tech. Bui. 58, 28 pp., Dec, 

 1922. 



