THE MICHIGAN PLANT DISEASE STTRVEY FOR 11)18. 



BY G. II. COONS. 



Following the plan of other years' a summary of the phuit disease condi- 

 tions for 1918 has been prepared. This summary attempts to interpret the 

 plant disease conditions of the year as affected by weather and to record the 

 data of occurrence of diseases and to give estimates of the extent of losses 

 caused. 



The agencies used in this summary consist of various members of the 

 staff of the Department of Botany, Extension Specialists of the College, and 

 federal field agents who were assigned to Michigan for special survey work. 

 By cooperative arrangement with the Office of Plant Disease Survey of the 

 Department of Agriculture. Dr. E. F. Woodcock was employed to spend three 

 months studying potato diseases as to their distribution and extent, and in 

 particular to locate the first outbreaks of late blight, should any appear. The 

 detailed report of this work is given by Dr. Woodcock' at another place in 

 this I'eport. I am incorporating some of Dr. Woodcock's observations on 

 cereal diseases, etc., in this report. Similarly, by cooperative agreement 

 with the Office of Cereal Investigations, eight field men were assigned to 

 investigate the extent of grain diseases in Michigan fields. Work was car- 

 ried into practically all the grain growing counties of Michigan. There is 

 iilso included a summary of insi)ection reports of the Bureau of Markets, in 

 .so far as they concern themselves with carload shipments of Michigan potatoes, 

 since these reports show the effect of plant diseas«is upon this important crop 

 in relation to marketing a salable prmluct. These reports were sent this 

 department for "follow-up" work with shippers having trouble, through the 

 courtesy of the Office of Cotton, Truck and Forage Crop Disease Investigations. 



This report, therefore, is a compilation from the above detailed sources, 

 and acknowledgment is made for the privilege of utilizing the data for this 

 summary. 



The Plant Disease Survey has a distinct place in the work of investigation 

 of plant diseases in the state. It is a work of a directive nature in that it 

 gives a picture of the happenings iB the state, and serves to focus attention 

 on the problems of most serious and pressing nature. It is important as a 

 device for determining progress in the use of control measures. It serves to 

 link the institution and the federal Department of Agriculture to the farm. 

 It develops facts as to severity of disease loss which furnish concrete evi- 

 dence of the losses from plant disea.«e and the urgent n«^d of control. In its 

 studies on the occurrence and eererity of plant disease it furnishee data which, 



'CoonB, G. H. Mich. Acad. Scl. Kept., 20 :426-449. 1918. 

 =Woodcock, E. F. Mich. ArmJ. Sri. Kopt. 21 : 1919^ 



51 ut Mich. Acad, Scl, Ropt., 1919. 



