20 BULLETIN 875, U. S. DEPARTMENT OF AGRICULTURE. 



take weevil poisoning by the use of a number of hand guns on this 

 area. This has generally proved very unsatisfactory. The labor re- 

 quirements of the guns are so great and, the operation so laborious 

 and difficult that labor troubles are certain to develop under any nor- 

 mal condition and this has generally resulted in preventing anything 

 like a satisfactory schedule for poisoning work. 



One important use of the hand gun is in conjunction with power 

 machinery. A great many fields have certain portions which are 

 very difficult to treat with power machinery, owing to the presence 

 of ditches, stumps, short rows, or similar obstacles. Attempts to 

 treat these portions of the fields with large machinery greatly reduce 

 the rapidity of the operation of the machine and frequently the cot- 

 ton is injured by being tramped and driven over. Under such condi- 

 tions the efficiency of the large machine is much increased if a few 

 hand guns with which to treat these difficult portions are available 

 for use at intervals. 



Hand guns are also of great value for the early-season work in 

 treating isolated spots of infestation which are often comparatively 

 small in extent. In much of the work which has been conducted in 

 the past, hand guns have been used in such fields for the first appli- 

 cation or two and a sufficient degree of control secured from this 

 work to make it possible to defer starting general poisoning with a 

 large machine until some weeks later than would otherwise have 

 been the case. 



Several instances have been noted where hand machines have been 

 offered for cotton dusting purposes with the distributing system di- 

 vided between two nozzles, the idea being that two rows could be 

 treated at each trip. None of the machines manufactured at present 

 have more than enough fan power to treat a single row satisfactorily. 



A number of hand guns have been offered for use in cotton dusting 

 with the blower constructed so that the dust delivery is intermittent. 

 As such guns are usually equipped with a bellows serving as a blower 

 the powder is expelled only in recurrent blasts. These are not satis- 

 factory for cotton work since it is necessary that the gun discharge 

 the dust continuously in order that uniform poisoning of all plants 

 be secured while the operator proceeds along the row. 



As has been stated, hand-gun work is mainly conducted in the 

 early morning and late evening, and this limits very much the 

 amount of territory which can be covered each day. Operation dur- 

 ing the night, however, is often entirely feasible and the results 

 from such operations are usually better than where treatments are 

 attempted during the day. Very satisfactory hand dusting can be 

 done at night by the aid of a small oil or carbide light attached to the 

 hat of each operator, or, in some cases, several hand guns may be 



