LETTER OF TRANSMITTAL 



XJ. S, Department of Agriculture, 



Bureau of Plant Industry, 



Office of the Chief, 



Washington, D. C, April 10, 1911. 



Sir: I have the honor to transmit herewith and to recommend 

 for pubhcation as Bulletin No. 217 of the series of this Bureau a manu- 

 script entitled ''Root-Knot and Its Control," by Dr. Ernst A. Bessey, 

 professor of botany, Michigan Agricultural College, formerly a plant 

 pathologist in this Bureau and now a collaborator of the Bureau of 

 Plant Industr}'. This bulletin presents the results and conclusions 

 of studjes made by the author while in the service of the Bureau. 



Root-knot, which is widespread through the warm temperate and 

 tropical zones of the whole world, is especially prevalent in this 

 country in the South, and, as the bulletin shows, it is present even in 

 the cold parts of the Northern States. It is also a very serious dis- 

 ease of greenhouse plants all over the country. Fortunately, it is 

 almost exclusively confined to the lighter types of soils, causing little 

 or no damage in stiff clays. Dr. Bessey has worked out under field 

 conditions a practical method of holding the pest in check. The 

 means of its control in greenhouses had already been worked out, 

 so that the methods presented here for controlling the pest in green- 

 houses offer little that is new. The list of plants susceptible to this 

 disease is more complete than any previous list published, contain- 

 ing more than double the names of any other list. 

 Respectfully, 



Wm. a. Taylor, 

 Acting Chief of Bureau. 



Hon. James Wilson, 



Secretary of Agriculture. 

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