THE DESEET COEN" FLEA-BEETLE. 19 



POISONS. 



Speaking in regard to the control of this flea-beetle on Sudan 

 grass, Dr. A. W. Morrill ^ states: 



Experiments with applications of Bordeaux mixture and arsenate of lead to the 

 infested grass failed to give satisfactory results. 



Later than this, after additional experiments, he remarks : ^ 



Spraying the plants with arsenate of lead, using one ounce of arsenate of lead 

 powder to one gallon of water, is the only remedial measure which can be recommended 

 at the present time. 



Prof. Freeman,^ m his bulletm previously mentioned, speaking of 

 the injury from this Httle flea-beetle, says: 



The plants were all sprayed twice with lead arsenate, but very little benefit could 

 be ascribed to this treatment. 



In correspondence with Prof. Freeman, the writer was informed 

 that he used arsenate of lead without soap m the solution, and he 

 says that the spray collected in drops upon the com fohage, and 

 attributes the failure of the arsenate of lead to this fact. 



The writer first used 1 pound of powdered arsenate of lead to 50 

 gallons of water, but without any success whatever, the beetles 

 being fuUy as numerous on rows treated as on those not treated. It 

 was easily seen that this was due to the fact that the solution of 

 arsenate of lead did not stick to the corn leaves. Later an experi- 

 ment was tried, using powdered arsenate of lead, 2 pounds to 50 

 gallons of water, mixed in a strong soap solution which caused the 

 diluted poison to stick well to the surface of the leaf. This seemed 

 to act both as a repellent and as a poison to the beetles, and the 

 treated rows were in no way injured by the attack of these flea- 

 beetles. While additional experiments must be carried on with 

 regard to the use of this poison, from the writer's past observations 

 it can be used in this manner upon small areas of corn, applied by 

 means of a small spray pump, with very satisfactory and practical 

 results. 



CULTURAL METHODS. 



As has been pointed out in the discussion of the pupal stage of 

 this flea-beetle, if the soil be kept fairly moist the pup£e wUl form 

 near the surfac<^ of tlu'. ground and within 2 or 3 inches of the corn 

 plant. Now, if precantions an*, taken to follow each irrigation by a 

 very shallow cultivation close to the plant and shallow enough to 

 insure no tearing of the root surface, a groat many pupa3 will be 



' Morrill, A. W. Rcpfjrt of thfj enlomoloKist of the Arizona Commission of Agriculture am] Jlortioiii- 

 turc. Ariz. <'om. A>;r. Tiort., Olli Ann. Kpl.., p. 'S.i, 1!)14. 

 2 .Morrill, A. W. The Com Vina, liwlle. In Ariz. Agr. Exp. Sta. Bui. 75, p. 408. May, luifi. 

 » Freeman, G. F. Papago sweet com, a now variety. Ariz. Exp. Sta. Uul. 75, p. 402. May, 1916. 



