Dusting for the Cotton-Boll Weevil. 8 
CART MACHINE. 
This term is used to describe the two-wheel, two-mule machine 
which straddles a row of cotton. It is the type most suitable for 
large farms. 
This machine will cover from-25 to 30 acres in a night of operation. 
One of these machines should be allotted not more than 100 acres 
of infested cotton for the season. 
This machine has three nozzles, but will usually cover four rows at 
a trip. | 
HOW TO DUST. 
Use only pure calcium arsenate in the form of a dry powder. 
Apply this only in the dust form. 
Purchase this to conform to the following specifications: 
Not less than 40 per cent total arsenic pentoxid. 
Not more than 0.75 per cent water-soluble arsenic pentoxid. 
Density not less than 80 or more than 100 cubic inches per pound. 
Use only dusting machinery especially constructed for cotton 
dusting. 
Dust only when the air is calm and the plants are moist. This 
practically means making only night applications. 
Use about 5 to 7 pounds of calcium arsenate per acre for ea 
application. 
Start dusting when the weevils have punctured from 10 to 15 per 
cent of the squares. 
Keep your cotton thoroughly dusted until the weevils are unde: 
control. This usually means about three applications at the rate of 
one every four days. 
Then stop poisoning until the weevils again become abundant. 
If the weevils become abundant early enough to injure your 
young bolls, make one or two more applications late in the season. 
If you have a heavy rain within 24 hours after dusting, repeat 
this application immediately. 
Do not expect to eradicate the weevils. Dusting merely controls 
them sufficiently to permit a full crop of cotton and you can always 
find weevils in the successiully poisoned field. 
Keep your cotton acreage low and do everything possible to in- 
crease your yield per acre, as it costs just as much to dust one quarter 
bale per acre cotton as bale per acre cotton. 
Always leave an occasional portion of a cut untreated for com- 
parison with the adjoining dusted tract. This will show how much 
you have increased your yield by dusting. 
If you are considering dusting, write to the Delta Laboratory at 
Tallulah, La., for more detailed information; also ask the advice of 
your county agent. 
