BULLETIN No. 164. 



NOTES ON PLANT DISEASES IN 1908. 



W. J. Morse. 



In connection with the regular Hnes of investigation under- 

 taken by the Plant Pathologists of this Station certain minor 

 problems are encountered and stiidied which of themselves are 

 not of sufficient importance to merit treatment in a separate 

 bulletin. It also seems desirable to record observations upon the 

 yearly prevalence and distribution of the more important plant 

 diseases and any new or unknown troubles which appear, par- 

 ticularly with reference to the apple and potato, around which 

 the major part of the work in this department now centers. 

 This bulletin has to do with certain subjects of this nature, 

 based largely upon the work of the current year. The following 

 topics are considered. 



Potato .Diseases of the Year p. i 



Orchard Diseases of the Year p. 3 



The Development of Scab on Limed Potato Soils p. 4 



Self-boiled Lime-sulphur as a Substitute for Bordeaux 



IMixture for Apple Scab p. 9 



Weather Records in Relation to Winter Injury of Fruit 



Trees p. !2 



Crotch Injury of Apple Trees Cause by \\'eather Con- 

 ditions p. 17 



"^'^^inter Injury of the AA'hite Pine in 1908 p. 21 



Potato Deseases oe the Year. 

 Leaf Blights. Late blight, Phytophthora infestans, did prac- 

 tically no damage in Mainj. even on unsprayed fields, during the 

 summer of 1908. This was due to the fact that dry weather 

 conditions prevailed over much of the State during the summer. 



