DIVISIOX OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 55 

 ROOT KOT OF FRUIT AND OTHER TREES. 



For several years the Division has been receiving" complaints from 

 varions parts of the United States in regard to the dying of fruit 

 trees as a result of the decay of the roots. The disease is especially 

 prevalent and destructive in the Mississippi Valley, where whole 

 orchards have been destroyed by it. During the year the special 

 agent in charge of the forest-tree diseases has also had the root-rot 

 trouble under investigation, and some important results have been 

 obtained. The cause of the trouble appears to be a fungus, and 

 from its nature and the way it works it may prove practicable to 

 prevent its attacks by the use of hardy or resistant stocks. This 

 matter is receiving thorough attention, and extensive experiments 

 are being inaugurated to obtain definite facts in regard to tlie ability 

 of different kinds of stocks to resist the disease. With the coopera- 

 tion of a number of large nurserymen in different parts of the United 

 States, and also of the Shaw School of Botany, the practical value of 

 the work can, it is believed, soon be determined. 



LITTLE PEACH DISEASE. 



"Work on little peach disease was continued during the year, parts 

 of Michigan and other States being visited for the purpose. As a 

 result of tlie investigations, some facts have been obtained which point 

 to the discovery of the cause of the trouble. Tlie disease is still 

 spreading, but was not so destructive the past year as previously. 



DISEASES OF COTTON. 



The w^ork on the diseases of cotton has been continued. Several 

 months were devoted to field work in the sea island cotton region, and 

 much information Avas obtained in regard to the various diseases which 

 have prevailed there during the past few years. In addition to labora- 

 tory studies made with a view of tracing the cause of the sea island 

 cotton disease, extensive field experiments were inaugurated for the 

 purpose of obtaining information as to the possibility of preventing it. 

 During the winter the work was continued at Washington, D. C, and 

 with the facilities furnished by the greenhouse a number of new facts 

 were brought out. 



ADDITIONAL GREENHOUSE FACILITIES. 



Through a small appropriation secured during the year additional 

 greenhouse facilities were made possible. The value of the entire 

 work of the Division can be greatlj' increased by proper facilities in 

 this direction. Heretofore the work has been much hampered through 

 lack of space, but with the increased room manj^ of the difficulties 

 will be overcome. The houses not only serve to make it possible to 

 continue many lines of work which would otherwise be stopped upon 

 the approach of winter, but also give opportunity for conducting inves- 

 tigations of direct practical bearing on subjects relating to forcing of 

 vegetables under glass and the growing of cut flowers for market. 



SUBTROPICAL GARDEN. 



The subtropical garden, located at Miami, Fla. , has been continued 

 and used largely for the planting of stocks and other Inijrid fruits 



