Z CIRCULAR 5 7 5, U. S. DEPT. OF AGRICULTURE 



Dusting with arsenicals, the most effective control method to date, 

 has proved expensive and was always accompanied with risk to grazing 

 livestock. The baits formerly tried, although less costly, did not 

 attract the crickets in sufficient numbers. When a Mormon cricket 

 project was authorized in 1935, attention was given to the development 

 of an effective bait and to determining the proper time for spreading 

 it. This circular is designed to give the results of these investigations 

 up to and through the season of 1939. 



PAST AND PRESENT METHODS OF CONTROL 



Until 1927 the most widely used methods of control consisted in the 

 application of modified grasshopper baits containing sodium arsenite 

 and the use of trenches, cricketproof fences, and barriers of oil and 

 water. Barriers of various kinds are still used, but baiting was dis- 

 carded by entomologists several years ago as impractical. Satisfac- 

 tory kills occasionally were obtained, but more often crickets refused 

 to eat the bait, and as a result little dependence could be placed on 

 this method of control. 



Control by dusting with powdered sodium arsenite and a suitable 

 diluent was developed by Shotwell and Cowan 2 in 1926 and 1927. 

 Since that time this has been recognized as the most reliable method of 

 killing crickets, but it has several serious disadvantages. (1) Unless 

 handled under the closest supervision, sodium arsenite dust is a 

 menace to the health of mixing and dusting operators and creates a 

 hazard to livestock when distributed on crops and range plants. 

 (2) The results of dusting are sometimes slow in appearing and are 

 much affected by weather conditions ; and the crickets, especially the 

 adults, may die several miles distant from where they were dusted. 

 Failure to find dead crickets on a dusted area frequently created the 

 impression that the work was ineffective. (3) Dusting is most suc- 

 cessful in a closely supervised, paid-crew type of control campaign. 

 Individual farmers and ranchers generally hesitate to use such dangerous 

 material and seldom possess the necessary equipment for mixing and 

 distributing the dust. (4) From an economic standpoint the greatest 

 disadvantage of the dusting method of control is the high cost, which 

 ranges from about 60 cents to $2.50 per acre, according to local 

 conditions and the equipment used. 



In spite of these disadvantages dusting with sodium arsenite powder 

 is an effective method of control, especially on extremely heavy con- 

 centrations of crickets. Such concentrations usually occur during the 

 early instars on the hatching grounds, and in the later stages while 

 the crickets are roosting during periods of hot weather. 



NEED FOR CONTROL BY POISONED BAITS 



Because of the high cost and other disadvantages of dusting with 

 sodium arsenite powder, it was felt that finding an effective bait was 

 essential in developing an economical method of Mormon cricket con- 

 trol that would be generally adopted. The long and widespread use 

 of poisoned baits for controlling grasshoppers has built up confidence 



s Shotwell, R. L., and Cowan, F. T. some preliminary notes on the use of sodium arsenite 



DUST AND SPRAY IN THE CONTROL OF THE MORMON CRICKET (ANABRUS SIMPLEX HALD.) AND THE LESSER 

 migratory grasshopper (melanoplus atlanis rhey). Jour. Econ. Ent. 21: 222-230. 1928. 



