GINNING 457 



to the surface. It has been shown, however, that arsenical 

 poison, appHed in dust form when the dew is on the plant, 

 is very efficacious. The weevil takes drink from the mois- 

 ture on the leaves. From 250 to 1,000 pounds more seed 

 cotton per acre, it is claimed, can be raised on sprayed than 

 on unsprayed plats. 



The bollworm is the larval stage of a moth which lays its 

 eggs on the stems and leaves of cotton and other plants. 

 The worm eats the leaves of the cotton and also buries itself 

 in the half-grown boll, eating the young seeds. The methods 

 recommended for the destruction of the boll weevil are also 

 effective with the bollworm. In addition, poisoning with 

 Paris green and the use of trap crops are recommended. As 

 the moths lay their eggs on the most readily available food 

 plants, many of the worms may be destroyed early in the 

 season by planting occasional rows of corn through the cotton 

 field and cutting and destroying these when the- worms 

 become numerous. 



FLAX 



625. Fiber Flax. The cultivation of this crop has already 

 been discussed (page 225). In the United States, flax is 

 grown almost entirely as a grain crop, and the use of the straw 

 for fiber is incidental. It is largely grown for the production 

 of fiber in some portions of Europe, particularly in Russia. 

 It ranks next to cotton in importance among vegetable fibers, 

 the annual production for the five years from 1907 to 1911 

 averaging 1,572,000,000 pounds as compared with 10,377,- 

 000,000 pounds of hnt cotton. 



HEMP 



626. History. Hemp is a native of western and central 

 Asia. It is one of the oldest of cultivated plants, dating back 

 at least 3,500 years. It is a member of the Moraceae, or 

 mulberry, family, to which the mulberry, the osage orange, 



