BUREAU OF PLANT INDUSTRY. 407 



velopment of the vegetative branches or of eliminating them alto- 

 gether. In order to effect a complete suppression of the vegetative 

 branches, it is usually necessary that the plants be less than 6 inches 

 apart during the early stages of growth, when the vegetative 

 branches would otherwise begin to develop from the basal joints of 

 the stalk. After this stage has passed and fruiting branches have be- 

 gun to grow, the plants may be thinned to wider distances without 

 inducing the development of vegetative branches. 



Leaf-curl injuries to cotton. — Observations on leaf -curl injuries 

 to cotton seedlings show that these malformations are of very gen- 

 eral occurrence and cause great damage to the crop. Though hitherto 

 confused with plant-lice injuries, the juvenile leaf -curl is a disorder 

 quite independent of the presence of plant lice. In addition to the 

 obvious effect of retarding the growth of the seedlings, the leaf-curl 

 is frequently responsible for a loss of the terminal bud. This de- 

 capitation of the young plants puts an end to the development of 

 the main stalk and results in permanent deformity and backward 

 development. Many of the injured plants fail to produce cotton, 

 and many others set only a few late bolls. Improved methods of 

 thinning are being devised to accomplish the removal of the de- 

 formed plants. 



Perennial cotton in California. — Attention is being given to 

 ihe fact that special conditions of climate and soil in southern Cali- 

 fornia make it possible to raise two or more crops of cotton from the 

 same planting, thus reducing the labor and expense of production. 

 Experimental plants of Egyptian cotton grown from the same roots 

 have continued to produce good crops for four or five j'ears. Though 

 the stalks are winterkilled to the ground, the new shoots that are 

 sent up from the roots in the spring grow more rapidly and produce 

 an earlier crop than plants raised from seed. Unfavorable condi- 

 tions that interrupt the growth of seedlings have less effect upon 

 the development of the o\erwintered plants and leaf-curl injuries 

 are largely avoided. Investigations are being made for the purpose 

 of improving the methods of cultivation applicable to the over- 

 wintered cotton in order to promote earlier and more regular de- 

 velopment of new shoots in the spring. 



Propagation of cotton hybrids. — The possibility of propagating 

 superior cott(m hybrids from cuttings is being investigated in south- 

 ern California. First-generation hybrids of Upland and Egyptian 

 cotton have been found superior to either of the parental stocks, but 

 deterioration in the later generations prevents the development of 

 hybrid varieties sufficiently uniform for purposes of production. A 

 few hybrid plants grown from fresh cuttings at Bard, Cal., in the 

 season of 1011 were extremely vigorous and productive. This result 

 led to a test of the po.ssibility of carrying cuttings through the win- 

 ter. Though no special precautions were taken, some of the cuttings 

 that were buried in sand in November remained dormant and were 

 still fresh in May. The next step is to learn satisfactory methods of 

 planting the cuttings, and experiments to this end are now being 

 made. 



Behavior of wild wheat in southern California. — An experi- 

 mental planting of the wild wheat from Palestine in 1910 was made 



