Insect Pests of Interest to Cotton Growers 189 



The greatest damage to cotton arises from cotton square daubers 

 being driven in from an adjoining alfalfa field when the crop is 

 cut. If the cutting begins on the side farthest from the cotton and 

 continues toward the cotton the square daubers and grasshoppers 

 are gradually concentrated on the side of the field and finally when 

 the last land is cut large numbers of the pests are virtually driven 

 into the cotton fields. In one such case an average of one of the 

 daubers to each cotton square was noted on a few rows. 



On account of both the square daubers and grasshoppers alfalfa 

 cutting and raking should be started on the sides of a field and 

 continued toward the central land which should be left temporarily 

 as a trap. When concentrated on a limited area in this way large 

 numbers of the insects can be captured with a hopper dozer such as 

 is used for grasshoppers. In one instance where the daubers aver- 

 aged one to a square foot, or about 43,000 per acre, more than 7000 

 of the insects were captured on a little less than an acre in the course 

 of fifteen minutes. In addition to the square daubers about 3500 

 specimens of the alfalfa hopper (Stictocephala festina Say) and about 

 1000 specimens of the differential grasshopper {Mclanoplus differen- 

 tialis) were captured at the same time. This was accomplished 

 after dark with two lanterns suspended over the pans of oil and 

 water.^ Further experience is necessary in order to perfect this 

 method, but the results so far justify the use of the hopper dozer 

 against the square daubers in alfalfa fields in cases of excessive 

 infestation, and especially after the insects have been concentrated 

 as advised above. Even if no attempt is made to destroy the insects 

 after concentrating them near the center of the field the method 

 will be of great advantage. The strip or patch of uncut alfalfa 

 should be left undisturbed until the rest of the field has made con- 

 siderable new growth. In the meantime, the grasshoppers should 

 be poisoned with poisoned baits, or both the grasshoppers and 

 square daubers collected with a hopper dozer, used at night to avoid 

 unnecessary scattering of the insect pests by driving away from 

 the trap patch many of those not captured. After the insects are 

 concentrated near the center of the field, prompt action against the 

 grasshoppers must be taken when necessary in order to prevent 

 their cleaning up the alfalfa leaving nothing but the bare stems. 

 In this condition the trap patch would not be effective in holding 

 the active square daubers. 



^To Mr. J. Li. Moore, a cotton and alfalfa grower located west of Phoenix, 

 credit is due for the idea of using- the hopper dozer at night. 



