EXPERIMENT STATION REPORTS. 243 



seasons, were reported. It was ver^' difficult to diagnose sueli diseases 

 as Mosaic and Leaf KoU, especially on the early planted tubers. The 

 weather conditions of the season however, were very favorable to the 

 potato leafhopper. The adult leafhoppers emerged early and due to the 

 comparatively high temperatuie tlie eggs hatched and the nymphs grew 

 to maturity in a minimum length of time. The result was that hopper- 

 burn was severe and caused considerable reduction in yield. 



Observations on the life history of the Potato Leafhopper, Ennpoasca 

 mali LeB, which causes hojtperburn were continued and control measures 

 were demonstrated. Bordeaux mixture was found to be effective in 

 warding off the leafhoppers and thus indirectly controlling liopperburn. 



An acre of potatoes was devoted to spray and dust experiments. Tlie 

 effectiveness of Bordeaux mixtuie as a spray for potatoes was demon- 

 strated. 



Potato seed treatment experiments were carried on after the plan of 

 the preceding year. In addition, soil treatment experiments were con- 

 ducted in an attempt to control potato scab, which seems to be inherent 

 in some of the limestone soils of the Upper Peninsula. Approximately an 

 acre of land was dievoted to these trials. 



The laboratory whicli was built during the early summer on the second 

 floor of the office building afforded an excellent place to carry on studies 

 on the casual organisms of tlie various diseases affecting the potato. The 

 laboratory work was .somewhat impeded through lack of pressure water 

 and drain for waste water, and in the latter part of the season through 

 lack of good artificial light. The need of electric lights was sorely felt. 

 As a whole, however, the laboratory is a marked improvement over condi- 

 tions of the preceding year. 



I take this opportunit}- to thank you for the hearty co-operation and 

 assistance you have given to further the potato disease investigations at 

 the Station. 



J. E. KOTILA, 

 Research Ass't in Plant Pathology. 



Rei^pectfullv submitted, 



D. L. McMillan, 



Superintendent. 

 East Lansing, Michigan, June 80, 1022. 



