POISONING THE COTTON BOLL WEEVIL 6 



When the infestation has been reduced to less than 10 per cent, dis- 

 continue poisoning until the weevils again become injurious. 



If weevils attack the young bolls late in the season, make such addi- 

 tional applications as are found necessary to protect those bolls. 



When fall migration begins with a general dispersal of weevils, it is 

 usually no longer profitable to continue poisoning for the protection 

 of squares, but frequently it is very profitable to make one or more 

 applications at this time if there is a crop of young bolls still subject 

 to damage by the weevil. 



If a heavy rain falls within 24 hours after poisoning, repeat the 

 application immediately. 



Do not expect to eradicate the weevils ; poisoning merely controls 

 them sufficiently to permit a full crop of cotton, and you can always 

 find weevils in a successfully poisoned field. 



Keep your cotton acreage low and do everything possible to in- 

 crease your yield per acre ; it costs just as much to poison cotton yield- 

 ing one-quarter bale per acre as to poison bale-per-acre cotton. 



If you are in doubt whether poisoning increases the yield, leave an 

 occasional portion of a field untreated for comparison with the adjoin- 

 ing poisoned area. This will show how much you have increased 

 your yield by poisoning. 



What Dusting Equipment to Use 



For applying calcium-arsenate dust on fruiting cotton there are 

 many types of machines adapted for different conditions. Each 

 farmer should carefully study his particular dusting problem and 

 select the machine most suited to his needs. The most important 

 types of apparatus are as follows : 



Hand gun. — The hand gun is the least expensive individual ma- 

 chine, but is recommended only when other types are not suitable. 

 One hand gun will treat only about 8 acres of cotton in a season. 



Saddle gun, — The saddle gun is operated from mule back by hand 

 cranking, and will care for from 40 to 50 acres of infested cotton 

 through the season. This machine has two nozzles, one extending 

 down on each side of the mule. 



One-mule machine. — The 1-mule machine is pulled by one mule 

 between two rows of cotton, and will care for about 60 acres of 

 infested cotton through the season. 



Traction cart duster. — The wheel-traction cart duster is usually 

 built with three nozzles and is pulled by two mules. This machine 

 will care for approximately 100 acres or infested cotton through the 

 season. 



Power cart duster. — The power cart duster has a fan turning at 

 high speed, operated by a gasoline motor, and permits dusting under 

 more adverse atmospheric conditions than any other machine used 

 on the ground. It is particularly suited for large areas or where 

 the absence of dew causes conditions comparatively unfavorable for 

 dusting. The different models vary considerably in capacity, bur 

 will usually care for from 200 to 300 acres of infested cotton through 

 the season. 



Airplane dusters. — For the last five years airplanes have been used 

 in commercial cotton dusting. Thev'are most useful on level land 



