jau. IS. 191S Three-Cornered Alfalfa Hopper 361 



PREVENTIVE MEASURES 



The great problem is how to control the species. While good may be 

 accomplished by any one of several methods, yet so far no way has been 

 found for entirely controlling the pest. Prof. T. D. A. Cockerell (9) in 

 1899 suggested that a hopperdozer might be used successfully, but 

 several attempts made during the fall of 191 3 by Messrs. R. N. and 

 T. Scott Wilson in which hopperdozers of different forms were used were 

 all unsuccessful. A device with merely the upright canvas back of the 

 oil pan caught only a very small percentage of the alfalfa hoppers. They 

 are so quick and active that they get away without even touching the 

 machine. When a forward projection of cloth was arranged so that the 

 hoppers could not get over the already high back, a few more were taken, 

 but the majority would fly out ahead and to one side, so that a hopper- 

 dozer seemed altogether impracticable. 



Prof. Osbom (11) suggested timing the removal of the crops so as to 

 destroy the eggs. While it is a certainty that many eggs are destroyed 

 in this way, yet the fact that a large percentage is laid close to the ground 

 and below the point above which they would be removed by the cutting 

 process precludes any possibiUty of this method being successful. 



In several instances fields that were pastured were found to be less 

 infested, but this may have been a coincidence, and at any rate could not 

 be utilized as a method of controlling the pest. 



The one practice that will bring about a considerable reduction of the 

 insects is clean methods of farming. When the time comes that each 

 and every farmer is cultivating only as much land as he has means to 

 handle properly — and by the term "handle properly" is meant the 

 tilling of his land in such a way that the maximum returns per acre will 

 be secured — then and then only will insect devastations be reduced to a 

 minimum. The alfalfa hopper can be greatly reduced by just such 

 handling, which must include the eradication of weeds, brush, bunches 

 of wild grass, rubbish, etc., along fences, ditch banks, and other places. 

 The fact that the alfalfa hopper is found during hibernation in places 

 where it is protected from cold and from exposure to its enemies shows 

 that a great many wintering adults may be eliminated by cleaning up 

 such hiding places. 



SUMMARY 



The three-cornered alfalfa hopper {Sticlocephala jesiina) is an insect of 

 economic importance to alfalfa crops in the irrigated valleys of the 

 southwestern United States and to alfalfa and cowpeas in the Southern 

 States. 



Injury is due to the sucking of plant juices by both adults and larvae 

 and the development of a feeding scar which often takes the fonn of a 

 ring or girdle and which is usually accompanied by a gall formation. 



Plants of the legume family constitute the favorite food. 



The eggs are deposited in the stems of the food plants, usually back 

 of the sheath leaves or below the surface of the ground. In cowpeas the 

 eggs are deposited in pockets on the stems. 



The egg period in Arizona occupies from 12 to 41 days and the five 

 stages of the nymphal period from 22 to 69 days. The average com- 

 bined length for both periods is about 50 days. 



