THE DESERT CORN PLEA-BEETLE. 19 
POISONS. 
Speaking in regard to the control of this flea-beetle on Sudan 
grass, Dr. A. W. Morrill x 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: 2 
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, 3 in his bulletin previously mentioned, speaking of 
the injury from this little 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 in the solution, and he 
says that the spray collected in drops upon the corn foliage, 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 fully 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 pupae will form 
near the surface of the ground and within 2 or 3 inches of the corn 
plant. Now, if precautions are 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 great many pupae will be 
1 Morrill, A. W. Report of the entomologist of the Arizona Commission of Agriculture and Horticul- 
ture. Ariz. Com. Agr. Hort., 6th Ann. Rpt., p. 33, 1914. 
2 Morrill, A. W. The Corn Flea Beetle. In Ariz. Agr. Exp. Sta. Bui. 75, p. 468. May, 1915. 
3 Freeman, G. F. Papago sweet corn, a new variety. Ariz. Exp. Sta. Bui. 75, p. 462. May, 1915. 
