128 EXPERIMENT STATION. [Jan. 



plant, which is located just below the surface, is more or less 

 blackened and deca} r ed, and often dead, the black areas and 

 decayed spots frequently extending below the crown of the 

 plant for some distance. Microscopic examinations of the 

 rather limited material which we have had at hand have re- 

 vealed no specific organisms associated with this trouble, al- 

 though fungi, bacteria and eel worms are usually found in the 

 decayed tissue, apparently as secondary factors or accompani- 

 ments of decay. In one instance plants were observed which 

 had perfectly clean cavities in the crown, as though eaten out 

 by some small animal ; and in other instances the so-called club- 

 foot or gall formation, containing eel worms, was noticeable on 

 the roots, but these did not seem to be responsible for the 

 trouble. Further investigations of this disease are at present 

 under way. 



8. Potato Diseases. 

 Potato foliage went through the season with comparatively 

 little disease. There was no blight of any importance. Some 

 potato crops always die down or mature earlier than others, 

 which is due in part to the conditions under which they are 

 grown, though it is often believed that this early maturity is 

 caused by some blight. The abundance of rain in the fall, 

 which followed the long drought, caused potatoes to rot badly 

 in some cases, especially when located on low and not easily 

 drained soil, but on the whole the season was favorable for 

 potatoes, the dry summer holding in check certain fungi which 

 are likely to be troublesome, especially during a wet summer. 

 On some fields, late in the season, following the period of rain, 

 a rather unusual outbreak of Cladosporium fulvam, Cke., oc- 

 curred, although this fungus is usually confined to tomatoes in 

 this section. 



9. Experiments with Fungicides. 

 Some potato-spraying experiments were made on the station 

 plots, for the purpose of testing and comparing certain spraying 

 mixtures to discover their adhesive properties, as well as their 

 value as fungicides. As there was little fungous infection on 

 the potato during the summer, the deductions which were drawn 

 from the various applications of fungicides are not of great 

 value. 



