1901.] PUBLIC DOCUxMEXT — \o. 



REPORT OF THE ROTAXTSTS. 



G. E. STONE, R. E. SMITH, 



The work of this division during the past year has con- 

 sisted as usual in the investigation of various forms of plant 

 disease, together with a large amount of correspondence, the 

 preparation of results for publication, and miscellaneous 

 botanical work. Bulletin No. 69, on "The rotting of green- 

 house lettuce," was issued during the year, giving an account 

 of the work on this subject, to which reference has been 

 made in several recent annual reports of this station. The 

 extent of the lettuce-forcing industry in this State makes 

 the subject of this bulletin one of great importance, as the 

 financial loss from this source has been a large and increasing 

 one. Notably in the case of the disease known as the 

 "drop," the least understood and the most destructive of 

 these troubles, results have been obtained which show hitherto 

 entirely unknown characteristics in the development of the 

 organism which causes the trouble, on the basis of which 

 knowledge a practical and efficacious treatment can be ap- 

 plied. Another result of no small importance has been 

 the demonstration of the worthlessness of many sf>-called 

 remedies. 



Our gi'eenhouses used for purposes of experiment have as 

 usual been devoted to the study of problems connected with 

 the forcing of vegetables, principally cucumbers, in addition 

 to lettuce. 



Aster Diseases. 



During the past summer, work on the diseases of the China 

 aster has been continued, upon a much more extensive scale 

 than heretofore. Altogether some 15,000 plants were grown, 

 and a great variety of experiments were conducted upon 

 fertilizers, varieties, localities, time of planting, methods of 



