78 



With this state of affairs the American farmer has found that the Hes- 

 sian Fly will be overcome by its parasites only temporarily, and then at 

 the expense of a larger per cent of at least one crop. By burning the 

 stubble we destroy all of the pest and also numerous other enemies 

 which are to be found in the fields at the time. The present season, 

 however, many of the flaxseeds were so situated that it is doubtful if 

 enough heat would have reached them to have destroyed them. 



In a rotation of crop the adults are obliged to travel about in search 

 of the fields, and there is a greater chance of their being destroyed while 

 thus engaged. This, however, has its exceptions, as we observed at Xew 

 Castle, about 30 miles northwest of Eichmond, Indiana, on November 17, 

 1888. The whole field had been sown in standing corn, a portion of it 

 about the 5th of September and the remainder considerably later. The 

 early sown portion had been seriously attacked and at least 85 per cent 

 destroyed; the later sown portion was only slightly injured, as was late 

 sown wheat generally in the community. Here at the Indiana Experi- 

 ment Station the plan of rotation is as follows : Corn one year, followed 

 by oats one year, wheat one year, clover and grass two years. The 

 wheat fields are never seriously affected by the ravages of the Hessian 

 Fly. 



Sowing narrow strips about the fields, early in the fall, as decoys, was 

 long ago strongly advocated by Dr. Fitch, but the advice has been, so 

 far as I have observed, totally ignored by the farmer. While it is 

 hardly possible to thus entrap the major part of the fall brood of larva?, 

 it is certainly possible to entice to these plats the stragglers and inter- 

 lopers, which we have shown to be capable of considerable injury. In 

 this way the farmer can, in a measure, continue the influences of sum- 

 mer and winter in sharply separating and defining the two broods. In 

 other words, while he can not eradicate the pest in this way, he can 

 weaken its power to commit serious injury. It is very doubtful if the 

 volunteer wheat, springing up after the wheat has been plowed, can be 

 used as decoys, and if allowed to stand until the date of sowing the 

 fields, these volunteer plants should, by all means, be plowed under 

 as deeply as practicable, or grazed off by pasturing. Simply killing 

 the plants will not do, as has been illustrated by the experience of Mr. 

 Oliphant, previously cited, and by the observations of Professor Forbes 

 in Illinois.* If volunteer wheat is allowed to stand at all, it should not 

 be for over a fortnight. The proper time for sowing these decoys will 

 probably vary with the latitude. For northern Indiana they should be 

 sown during the latter part of August, and in the southern part of the 

 State not later than the first week in September. To the north and 

 south of this I have, as previously stated, no definite information as 

 to the date of appearance of the fall brood of flies, and hence can not 

 undertake to settle the date of sowing. These decoys should not be 

 permitted to stand over four weeks at the farthest, and should beplowed 



* Bulletin 3, State Eut.. 111., p. 43, 1887. 



