338 Annual Report Agricultural Experiment Station 



hoppers can then be destroyed by means of a comparatively heavy 

 application of poisoned bait or by means of a hopperdozer. The 

 hopperdozer proved successful in capturing large numbers of other 

 destructive insects, particularly cotton square daubers and the three- 

 cornered alfalfa hopper. In one test the daubers were captured at 

 a rate of more than 7000 of the insects per acre. It is estimated 

 that this number of the square daubers liberated in or driven into 

 an Egyptian cotton field would be capable of doing damage amount- 

 ing to between $5.00 and $15.00 per day. The cost of using the 

 hopperdozer would not exceed 25 cents per acre. Even if the in- 

 sects are not destroyed by this or other means it is very important 

 in cutting alfalfa that they be driven into the middle of the field 

 or away from the cotton rather than toward it. 



The cotton square daubers are active fliers and if disturbed 

 when feeding quickly emerge from the feeding place inside the 

 bracts of the square and dart away, usually alighting on another 

 plant a few feet distant. Two contrivances have been designed by 

 the writer for the protection of cotton fields against these insects. 

 The first is for the purpose of driving the bugs to the outside rows 

 of the field where, when concentrated, they may be captured by 

 means of the second device. Even if the insects are left concen- 

 trated on the outside rows there is a decided advantage in this 

 system, since two or three of the insects per plant are sufficient to 

 destroy all the squares as fast as they are developed, and concentrat- 

 ing the insects on outside rows so that there will be several times 

 as many of them per plant can not, therefore, result in any additional 

 injury. When concentrated in excessive numbers, however, there 

 would probably be a tendency for the insects to spread out again 

 over the field unless some other means was used against them. An 

 important feature of the work planned for the coming season con- 

 sists in the development of the devices mentioned to a point where 

 they can be recommended to cotton growers. 



Publications by the Consulting Entomologist during the fiscal 

 year included the Annual Report of the State Entomologist in the 

 Ninth Annual Report of the Arizona Commission of Agriculture 

 and Horticulture, pages 15 to 61, December 30, 1917, and a paper 

 entitled "Experiments with Grasshopper Baits, with Incidental Ob- 

 servations on the Habits and Destructiveness of the Differential 

 Grasshopper (Melanoplus diffcrcntialis)" in Journal of Economic Ento- 

 mology, Vol. II. No. 2. pp. 175-186, April 1918. 



A. W. Morrill, 



Consulting Entomologist. 



