272 STATE BOARD OF AGRICULTURE. 



observers iu nearly every potato county in the State. A cousdrvative es- 

 timate would put the money loss at |4,000,0()() last year. This money is 

 a total loss, except in so far as it dii'ccts attention to the greatly neg- 

 lected work of potato spraying. The study of the epidemic of 1912 (|2,- 

 000,000 loss) and the epidemic of 1915 as related to weather conditions 

 has led to certain correlation with the weather and this is being pre- 

 pared for publication. 



Cercospora concors one of the minor potato leaf-spot fungi, was dis- 

 covered at Marquette, Michigan, last September. 



The discovery of the Powdery Scab at various points in Minnesota 

 gave warrant to the suspicion that the disease was present in Michigan. 

 The county agents in suspected districts were notified, but as yet, no 

 case has been discovered. No thorough survey by a plant pathologist has 

 been made, but the seriousness of the disease well warrants a careful 

 search. 



Black Leg of potato continued serious in many fields of the Upper 

 Peninsula. It was found doing much damage late in the season. In one 

 field 25% of the vines were found diseased early in September. The dis- 

 ease progressed in the wet period which followed until 75% O/f the vines 

 were rotted. Potatoes from the same car which had been carefully 

 sorted in the fall and again in the spring and which were treated with 

 formaldehyde for scab gave a crop which showed less than 1% Black 

 Leg. The soil in these two plantings were similar in kind and neither 

 soil had had potatoes the previous year. The results of these plant- 

 ings point to poorly sorted potatoes as a source of the trouble, and in- 

 dicate a dispersion during the growing season. 



Black Leg was found in Kalamazoo, Kent, and St. Clair counties last 

 year. It seems safe to say that it occurs only sparingly in the Lower 

 Peninsula. The question is as yet unsettled as to whether the compara- 

 tive freedom of the lower part of the State as contrasted with the wide- 

 spread occurrence in the Upper Peninsula is due to climatic differences, 

 or whether it is due to lack of introduction of the parasite. It should 

 be noted that the Black Leg found in Kalamazoo county occurred on 

 seed introduced from the north. 



GRAIN DISEASES. 



Urocystis occulta, a serious smut of Rye has been found by Dr. Bes- 

 sey. In one field 5% of the heads were found, by actual count, to be 

 affected. The seriousness of this disease is as yet problematical. There 

 is the possibility of its becoming as great a pest as oat smut. In a rye- 

 growing state like Michigan such an occurrence would be a calamity. 

 This disease illustrates the great need we have of facilities for initiating 

 a vigorous careful survey to determine the seriousness and possibility of 

 spread of such a parasite. Wheat scab was reported iu Kalamazoo 

 county as causing from 25% to 50% loss in affected fields. 



VEGETABLE DISEASES. 



The onion crop last year was cut practically in two by an epidemic of 

 Downy Mildew caused by Pcronospora schleideni: This disease and neck 

 rot have been found by Mr. Muun of this department to be deciding fact- 



