388 ANNUAI. liEPOKT OF THK Off. Doc. 



Treatment. 



There are several ways in which the injuries caused by the Hes- 

 sian Fly may be reduced, though no one of these is of itself suffi- 

 cient to give entire protection. 



Late fall planting is generally a method of control which is quite 

 successful. The flies api^ear during the latter part of August and 

 first of September and by the last of the latter month have died. If 

 the wheat be planted as late as the twentieth of September, there- 

 fore, the flies will be gone before it has come up and no eggs will be 

 laid upon it in most cases. Unfortunately, however, this date is not a 

 fixed one for different latitudes and elevations. In southcaslern 

 Pennsylvania it might be necessary to delay planting for a week or 

 more after this date, while in the higher lands of the northern parts 

 of the State sowing could perhaps begin as early as the tenth of the 

 month with success. 



The fear that wheat sown as late as the twentieth of September 

 will suffer the following winter is practically groundless, as a large 

 amount of growth is unnecessary, for the above ground portions are 

 mostly destroyed in any case. 



One factor bearing on the date at which wheat should be sown to 

 escape the attacks of the fly, is that of the weather conditions. A 

 hot, dry August seems to delay the fall brood of this insect, which 

 accordingly appears later than usual and is able to attack the late 

 sown wheat. This w'as noticeably the case in Pennsylvania in the 

 fall of 1900, and in some cases at least, threw discredit on the plan of 

 late planting. 



If sowing after the twentieth of September be practiced, it is quite 

 important to have co-operation with all wheat-growing neighbors. 

 If ten or a dozen wheat-growers should agree to plant late, and one 

 should refuse, the fly will find abundant opportunity to lay its eggs 

 on the wheat of the latter and thus produce a supply of insects which 

 will, the following spring, spread to the surrounding wheat fields 

 and lay their eggs for the spring brood, thus rendering late plant- 

 ing the previous fall a failure, at least in part. 



A trap strip of wheat planted early in August is an excellent, but 

 too seldom used, method for controlling this insect in connection with 

 late planting. Such a small strip sown along one side of the field 

 which is fo be planted later will bo available for the flies to lay 

 their eggs on, and after egg laying has been accomplished the flies 

 very soon die, or if they should live would of course no longer be 

 dangerous to the main crop. This trap strip should be plowed under 

 before the wheat in the field comes up, thus destroying multitudes of 

 ihe young. 



Burning the stnbble soon after reaping is a valuable treatment, as 



