BUKEAU OF PLANT INDUSTRY. 303 



Crop-infestixg nematodes. — From a study of three main crops of 

 the country it is becoming clear that the number of their nematode 

 enemies, especially those attacking the roots, is so great as to demand 

 immediate further investigation. Hitherto the inquiries on this sub- 

 ject have related largely to the number and nature of the species of 

 nematodes found attacking these crops and the extent of the injury 

 due to their attacks. From a comparison of the specimens thus far 

 examined it is possible to draw certain general conclusions, and these 

 conclusions show the strong advisability of carrying out tests to 

 settle more definitely the nature of the injury caused by a certain class 

 of these pests with a view to devising combative measures. In the 

 future it is proposed to give this work increased attention. Prelimi- 

 nary physiological tests made during the past year haA^e indicated 

 the lines along which the new investigations will have to proceed. 



Improv-ed methods of producing illustrations. — The installations 

 made in the laboratory for the purpose of producing illustrations 

 and measurements have been further improved and utilized during 

 the past year. The methods first adopted in these installations are 

 being adopted elsewhere. The apparatus so far installed is of the 

 greatest service in connection with the work on cotton standardiza- 

 tion and on paper-making plants. These new devices are frequently 

 consulted by experts both in and out of the Department, and explana- 

 tions of their underlying principles have been made upon request. 



FIBER-PLANT INVESTIGATIONS. 



The investigations relating to plants producing textile and brush 

 fibers have continued in charge of Mr. L^^ster H. Dewey, Botanist. 

 During the past year the work has been devoted chiefly to hemp, 

 flax, sisal, and zapupe. 



Hemp in\t;stigations. — Hemp grown on the state farms in Wis- 

 consin in 1909, in cooperation with the state experiment station,, 

 has been retted and broken under the direction of this office. The 

 yield and quality of fiber compare very favorably with hemp grown 

 in the bluegrass region of Kentucky. The destruction of Canada 

 thistle, quack-grass, and other weeds by the dense shade of the grow- 

 ing hemp, and the excellent physical condition of the soil after this 

 crop, together with the profits in the cultivation of hemp for fiber, 

 have aroused the interest of Wisconsin farmers. Further experiments 

 are being continued in Wisconsin in 1910, and work along similar 

 lines has been begun in Iowa in cooperation with the Iowa Agri- 

 cultural Experiment Station. 



A study of the history of hemp has shown clearly that all of the 

 best fiber-producing varieties are derived from the giant hemp, "ta 

 ma," of China. Several samples of Chinese seed obtained by the 

 Offiice of Foreign Seed and Plant Introduction are being carefully 

 tried in order to procure improved varieties. 



Flax investigations. — More than 1,000 plants were selected in the 

 fiber-flax fields of eastern Michigan in 1909. By careful laboratory 

 tests these were reduced to the 100 best plants. The seed from each one 

 of these was carefully planted in the spring of 1910 in separate plats, 

 and the resulting plants are being subjected to a rigid selection. The 



