330 ANNUAL REPUllTS OF UKrAKTMENT OF ACJKICULTURE. 



Effort lias been made to reach every man who is poisonin*^, and 

 to aid him with such advice as seems best suited for his particular 

 case. Coiiseciuently it has become necessary to extend the Avork to 

 inchule new territory and new conditions. New lield stations have 

 been established in southern Louisiana, central Mississippi, southern 

 Alabama, eastern (Jeoi-fi^ia, and southern South Carolina. In each of 

 these loialities observations are conducted to determine the activities 

 of the weevil under the dill'erent conditions prevailing as affecting 

 j)oisonin<r oi)erations. Close check is also kept on the work of the 

 farmers. 'J'he results secured are carefully noted and the condi- 

 tions ijilluencing these results arc studied in an effort to standardize 

 advice. Throughout all of this work, as well as the operations con- 

 ducted under the direction of the Delta Laboratory, unpoisoned check 

 plats are maintained under varying conditions in order that the exact 

 limitations of ])roHtable weevil control may be determined. 



Semitechnical studies, consisting of plat work and cage studies^ 

 are being continued with a view of improving methods of poisoning. 



The extensive production of calcium arsenate has necessitated the 

 development of a very lar^e project handled in cooperation with the 

 Federal Insecticide and Fungicide Board. Improperly made cal- 

 cimn arsenate may either fail to control the weevil or may kill the 

 cotton plant. Prior to 1919 the manufacture of calcium arsenate 

 was limited, while at the present time over 20 companies are in the 

 market, and this has meant the production of large quantities of in- 

 ferior material. For their protection, farmers have been advised to 

 buy this chemical on certain specifications and to send samples of the 

 material purchased to the Delta laboratory for analysis before using 

 it. This has resulted in preventing the use of large quantities which 

 would have been very destructive to the cotton, and has involved 

 the analysis of over 2,000 samples of calcium arsenate. These 

 analyses have been made by chemists in the employ of the Insecticide 

 and Fungicide Board. In addition the official inspectors of this 

 board have been assigned to the work and have sampled many of 

 the larger shipments. Portions of each of these samples are tested 

 on plants at the Delta laboratory, and if found dangerous court 

 proceedings have been started and seizures made under the insecti- 

 cide act of 1910. This work has resulted in saving many crops of 

 cotton and has prevented weevil poisoning from becoming too 

 dangerous and thus falling into disrepute. 



Another important phase of the investigations has been the de- 

 velopment of suitable dusting machinery. Motor-power dusters 

 proved unsuitable owing to the type of labor available for operation^ 

 and a new machine operated by wheel-traction power was developed 

 in cooperation with the Bureau of Public Roads. Blue prints were 

 prepared covering this type of machine and furnished to all inter- 

 ested manufacturers. Several models were placed on the market and 

 more manufacturers are taking them up. The experimental depart- 

 ment is now at work developing a cheaper form of wheel-traction 

 machine which will be suitable for the small farmer who has an area 

 too large to cover with hand guns. In additon to this work, manufac- 

 turers have been encouraged to forward test machines, many of which 

 have been tried out and advice given for their improvement, all aim- 

 ing toward providing the cotton farmer with the best and most 



