REPORT OF THE SECRETARY. 79 



Further investigations have been begun with a view of still further 

 cheapening the hydrocyanic-acid gas process for the fumigation of 

 orange trees against scale insects in southern California. The results 

 previously announced have brought about enormous economy in these 

 methods, and work going on at the present time promises to cheapen 

 them still further to a degree which will result in very great benefit 

 to the growers. 



OTHER WORK. 



The Mexican cotton boll weevil has continued to spread somewhat, 

 and has reached western Florida. Owing to the early cold weather of 

 the autumn of 1911, certain territory in the northern range of this 

 species was at least temporarily rid of the pest, the early freeze catch- 

 ing them in the larval condition. Work on the testing of control 

 measures has been carried on in the Mississippi Yazoo delta, and the 

 study of the parasites of the species has been continued, while 

 attempts have been made to locally concentrate parasites from one 

 region into another. 



Work upon tobacco insects and the insects affecting sugar cane has 

 been continued. An extensive experiment has been carried on in New 

 Orleans in the effort to eradicate totally the sugar-cane borer which 

 bids fair to be successful in this locality. 



The Argentine ant has been shown to be most injurious to orange 

 plantations in Louisiana and now threatens to spread to the orange 

 groves of Florida. Measures of control so far ascertained have been 

 reasonably successful, but it is difficult to secure their general 

 adoption. 



The work on the cotton red spider in South Carolina has indicated 

 the food plants upon which this creature passes the winter, and a 

 spray of jootassium sulphide in water has been shown to be an eco- 

 nomical and effective method of destroying the spider Avhen it has 

 invaded a field. Work with this solution can be successfully carried 

 on at an expense of 75 cents per acre. 



Large-scale spraying operations against the pear thrips have been 

 carried on as demonstrations in California. Nearly 15,000 acres of 

 orchards have been sprayed under the direct supervision of the bureau 

 and with excellent results. 



Field work against the onion thrips has been continued in Texas 

 and Indiana. Good control measures have been discovered ajrainst 

 this insect, and with widespread cooperation it is believed that the 

 damage which it does may be largely stopped. 



THE MEDITERRANEAN FRUIT FLY. 



The appearance in destructive numbers of the so-called Mediter- 

 ranean fruit fly in the Hawaiian Islands attracted much adontion, 

 especially from the State of California, since it was feared that the 



