INSECT ENEMIES — PACKARD 331 



With recurrent grasshopper outbreaks in many other States the 

 method gradually came into much wider use (pi. 10) and its effective- 

 ness against armyworms and cutworms as well as grasshoppers became 

 more generally known. Many attempts were made to increase the 

 efficiency of the bait by the addition of flavorings of one kind or 

 another, such as cane molasses, ground citrus fruit, or banana oil, to 

 make it more attractive to the grasshoppers. Up to the present time, 

 however, the wheat bran itself, and products closely related to it, have 

 proved to be about the most attractive, most widely available and 

 cheapest material suitable for large-scale use. The effectiveness of 

 bran baits has not been increased enough by any other attractants yet 

 found to warrant the trouble and cost of adding them. On the other 

 hand, it has been found possible to dilute the bran greatly with cheaper 

 inert flalfy substances, particularly wood sawdust or cottonseed hulls, 

 without materially reducing the efficiency of the bait. As a result of 

 this discovery tlie cost of bait per acre has been much reduced and 

 the funds available for control operations have been made to go much 

 farther in recent years than formerly. The quantities of bait used 

 during the years 1939, 1940, and 1941 for the control of grasshoppers, 

 and the crop savings realized thereby are given in the table on page 324. 



Large quantities of bait have also been used during the past several 

 years in the control of armyworms and Mormon crickets. It is only 

 within the last 3 or 4 years that bait has been used successfully against 

 the latter. Although the Mormon cricket (pi. 11) is really a big 

 wingless grasshopper and likes tlie same crops, it will have little to do 

 with the standard bait in which an arsenical is used as the poisonous 

 ingredient. For many years this was thought to be due to all sorts of 

 reasons except the right one. Finally Cowan and Shipman learned 

 from their experiments that the crickets refuse to eat baits containing 

 an arsenical even in extremely small quantities but that they will take 

 them readily when sodium fluosilicate is substituted as the poisonous 

 ingredient. This discovery has resulted in much cheaper and more 

 effective control by baiting than was possible by any of the methods 

 previously used, which included dusting the crickets with sodium 

 arsenite and the installation of barriers and traps of one kind or 

 another (pi. 11) to dispose of the migrating bands. 



Sodium fluosilicate bait is also just as effective against grasshoppers 

 as the arsenical bait and, owing to the scarcity of arsenicals as a result 

 of war conditions, is supplanting it in grasshopper-control operations. 

 Fortunately, no scarcity of sodium fluosilicate has yet developed. 

 Another very valuable feature of the fluosilicate is its distastefulness 

 to livestock and the probable elimination through its use of the 

 accidental poisoning of stock which sometimes occurs as the result of 

 carelessness in the handling of arsenical bait or sodium arsenite dust. 



In the large-scale publicly supported campaigns of recent years, the 



