CONTROL OF MORMON CRICKET WITH POISONED BAIT 



baits became apparent immediately on adoption of this method. 

 Unpoisoned crickets captured by the same method and held in check 

 pens showed little or no mortality in 4 days. 



In each series of tests the baits were replicated from 7 to 15 times. 

 The data were then analyzed by the method of analysis of variance 

 whereby an estimate of error associated with the mean percentage kill 

 of each bait was obtained. With the aid of this statistic the sig- 

 nificance of the difference between any two means could be judged. 



The pan-bait method developed by Parker and Seamans 3 to test 

 grasshopper baits was used to determine the effect of weather and 

 time of day on cricket baiting. Small pans, each containing a bait, 

 were arranged in a row in an infested field. Counts of the number of 

 crickets feeding on the different baits were made every 10 minutes 

 throughout the day. At the same time records of air and soil temper- 

 atures, as well as the extent of cloudiness and velocity of wind, were 

 made. Baits were stirred or changed every half hour in order that 

 fresh bait would be available at all times. 



MATERIALS TESTED 



Over a period of 5 years 40 different baits were tested. In these 

 baits attractants such as cane and beet molasses, amyl acetate, and 

 salt, which were commonly used in grasshopper baits, were tested 

 either alone or in combination with one another with standard bran 

 as the carrier. In addition to these so-called grasshopper attractants, 

 several materials, including tankage, ground onions, tobacco extract, 

 and dried orange pulp, thought to be especially attractive to the 

 Mormon cricket, were tested. 



In other tests various carriers, including bran, dried beet pulp, and 

 cracked wheat, were used alone; and mill-run bran, shorts, flour, 

 rolled wheat, and ground soybeans were tried in various combinations 

 with sawdust. 



Various poisons, including liquid sodium arsenite, sodium fluoride, 

 sodium fluosilicate, paris green, crude arsenic, calcium fluoride, and 

 synthetic cryolite were tested at some time during the period 1935-39. 



EXPERIMENTS TO DETERMINE THE BEST CARRIER 



The experiments of 1935 were conducted to determine the efficiency 

 of various carriers. Sampling was made by the closed-pen method, 

 in which the percentage kill from each bait was obtained from 14 

 replications. One quart of sodium arsenite (8-pound material, 

 approximately 60 percent As 2 3 ) and 12 gallons of water was used with 

 100 pounds of each carrier. The results of the tests are as follows: 



Average 

 kill 

 Carrier {percent) 



Standard bran 37. 



Sawdust, 1 part ; mill-run bran, 3 parts 28. 8 



Sawdust, 3 parts; flour, 1 part 27. 5 



Sawdust, 3 parts; shorts, 1 part 27. 4 



Cracked wheat 21. 2 



Dried beet pulp 10. 3 



Standard error of any average, 3.42 percent. 



Minimum significant difference, 9.61 percent. 



3 Parker, J. R., and Seamans, H. L. experiments with grasshopper baits. Jour. Econ. Ent. 14: 

 13S-141. 1921. 



