to be cut before the immature stages therein have sufficiently 

 developed to emerge as adults. Of course the trappatch will 

 be the more efficient the more the seed heads of Johnson 

 grass nearby are made to serve as traps and are finally kept 

 down before adults can develop through pasturing or mowing. 

 "Johnson grass makes a heavy yield of excellent hay if cut 

 before the seeds are formed ..." Farm Bull. No. 509, p. ?'). It 

 is quite possible to eradicate it in fields planted by itself "with- 

 out excessive labor or expense. . . . The only expense is for 

 the extra plowing and harrowing and that is more than repaid 

 by the additional crop . . ." (p. 7). Also see Farmers' Bulletin 

 No. 279 : A method of eradicating Johnson grass. But as 

 Johnson grass also occurs in mixture with other grasses and 

 weeds where proper shallow plowing and harrowing for eradi- 

 cation cannot be employed, if we were to adopt the Bureau's 

 plan of controlling the sorghum midge by eradicating the 

 Johnson grass, we would have to dig all these scattered root 

 stocks up, simply to have new grass sown through seeds pass- 

 ing through the stomachs of birds and other animals and to 

 find that a large number of other grasses are also capable of 

 sustaining the midge. 



That Mr. Dean does not know how to eradicate Johnson 

 grass is plain from the following, under heading of Destruction 

 of Johnson grass : "... It should be burned over whenever 

 discovered and such areas plowed in the spring to prevent an 

 earh 7 crop of heads" (p. 58). The fact is, such plowing prevents 

 an early crop of heads all right, but keeps the grass growing 

 from year to year" . . . The small isolated patches of the grass 



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