The Tobacco Biidworm. 9 



From Table 1 it will be seen that where antimony sulphid had 

 been used at the rate of 1 pound to 24 pounds of corn meal, 98.35 

 per cent of the leaves were free from budworm and poison injury; 

 and that where arsenate of lead had been used at the rate of 1 

 pound to 75 pounds of corn meal, 98,25 per cent of the leaves were 

 perfect. The cost of the applications of antimony sulphid per acre 

 per season was $2.26 more than for the arsenate of lead, and of 

 course the difference of one-tenth of 1 per cent in the efficiency of 

 these applications in favor of the antimony sulphid would not com- 

 pensate for the extra expense. 



Where Paris green had been used at the rate of 1 pound to 150 

 pounds of corn meal, 92.5 per cent of the leaves were free from in- 

 jury — 5.75 per cent less than where arsenate of lead had been ap- 

 plied — and the cost of application per acre per season was 26 cents 

 less than for the arsenate of lead. The injury following the use 

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

 In studies made in the Bureau of Entomology 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 arse- 

 nate of lead costs 26 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 ancl 75 pounds of corn 

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

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

 necessary in controlling budworms, it is impossible to avoid 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 any amount within reason is used. 



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

 vforms than those mixed with other carriers. This material ap- 

 pears to be attractive to the worm, apparently serving as a bait, 

 v^^hereas other carriers seem more or less distasteful. 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 often become compact and cause damage such as takes place 

 when other carriers are used. 



As calcium arsenate is now being used rather extensively through- 

 out the South as a poison for the cotton boll weevil, a word of warn- 

 ing may be needed in regard to its use in a budworm poison mixture. 

 Calcium arsenate has been tried with various carriers and in various 

 strengths over a period of several years and has invariably given 

 unsatisfactory results. 



Even in very dilute quantities, calcium arsenate burns tobacco 

 severely, especially in rainy weather, and if used strong enough to 

 serve as an effective poison it usually causes serious damage. 



Tests have shown that the effectiveness of arsenate of lead when 

 employed against the budworm varies with the carrier with which 

 it is used, as indicated in Table 2. 



