THE TOBACCO BUDWOKM AND ITS CONTROL. 9 



use of Paris green has been shown to result in a loss of $37.50 per 

 acre, and arsenate of lead has been shown to save $28.75 of this 

 amount, the actual saving due to the use of arsenate of lead is $28.75 

 minus 26 cents (for arsenate of lead costs 20 cents per acre more than 

 does Paris green), or $28.49. It will be understood, therefore, that 

 the possibility of incurring a loss of $37.50 per acre will not justify 

 the use of Paris green to effect a saving in material of 26 cents per 

 acre. 



A mixture of 1 pound of arsenate of lead and 75 pounds of corn 

 meal has proved to be the most efficient combination against bud- 

 worms. As already stated, on account of the method of application 

 necessary in controlling budworms, there must be some variation 

 in the quantity applied to each bud. The arsenate of lead and corn 

 meal mixture can be employed without fear of injury in case too 

 great a quantity is used. 



Poisons mixed with corn meal are more readily fed upon by bud- 

 worms than those mixed with other carriers. Then, too, corn meal 

 is the most desirable material for this purpose because it does not 

 interfere with the development of the immature leaves. Even when 

 saturated during periods of showers, corn meal does not become 

 compact and cause damage such as takes place when other carriers 

 are used. 



Tests have shown also that the efficiency of arsenate of lead when 

 employed against the budworm varies with the carrier with which 

 it is used, as indicated in Table 2. 



Table 2. — Relative effiricncy against the tobacco btidtrorm of arsenate of 

 lead ivith different carriers. 



Experi- 

 ment No. 



Budworm 

 injury. 



Arsenate of lead, 1 pound; corn meal, 75 pounds 



Arsenate of lead, 1 pound; gypsum, 25 pounds 



Arsenate of lead, 1 pound; Fuller's earth, 16 pounds. 



Percent. 

 0.79 

 3.00 

 2.50 



In experiment No. 1 arsenate of lead was used at the rate of 1 

 pound to 75 pounds of corn meal and only 0.79 per cent of leaves 

 showed injury. In experiment No. 2 the arsenate of lead was used 

 three times as strong as in experiment No. 1 (1 pound to 25 pounds) 

 but with gypsum as a carrier. Three per cent of the leaves were 

 injured — nearly four times as many as in experiment No. 1. In ex- 

 periment No. 3 the arsenate of lead was used nearly five times as 

 strong as in experiment No. 1, yet the leaf injury amounted to 2.5 

 per cent — more than three times that in experiment No. 1. These 

 experiments indicate that of the three carriers corn meal is pref- 

 erable in budworm control. 



