46 THE HESSIAN FLY IN THE UNITED STATES. 
surface of the ground or below it, it will be seen that there is little 
basis for favorable results in this method. If the flies are noted as 
depositing freely at a particular time, and sheep or other stock are 
turned in at once in sufficient numbers to graze the crop pretty closely, 
a considerable redaction of larva 4 might result. The method, however, 
iuvolves pretty close observation on the part of the fanner to deter- 
mine the fact of deposition. 
ROLLING. 
The suggestion that the passing of a heavy roller over the ground 
will serve to crash the eggs has been commented on by Fitch. He 
suggests tbat it may be successful, particularly on fields that are so 
smooth and free from stones that almost every plant will receive a firm 
pressure by the operation. Necessarily the method must be applied 
immediately after deposition of eggs, and Fitch suggests that some 
plan of brushing the leaves would be still more effective by dislodging 
the eggs and preventing the larvae from following their usual course 
into the sheath of the young plant. 
Of this method Fitch says: 
Mr. Goodhue, of Lancaster, Wis., in a communication in the fifth volume of the 
Prairie Farmer, suggests that the larva} concealed within the hase of the leaves 
may be destroyed by mowing the wheat and feeding it to the stock. We deem this 
proposal a valuable one for exterminating the second or spring brood from a wheat 
field. In those cases where the worms are discovered in the month of May to be 
fearfully numerous at the joints of the young stalks, there can be little doubt but 
that on smooth ground the scythe may be so used as to take off almost every spear 
below where the larva) lodged; and that thus a second growth of stalks will be 
produced, quite free from these depredators. The following facts lead me to believe 
that on a fertile soil wheat may be thus mowed with little if any eventual injury to the 
crop. Portions of a field of my own, the past season, grew so rank that, deeming that 
it would become lodged and mildewed, by way of experiment a space in it was mowed 
down after the plants were two feet in height, and another after the heads had 
begun to put forth. Though not so early in ripening, the appearance of these two 
patches at harvest proved, so far as a single experiment could do, that wheat might 
be mowed at the former period without any diminution of its productiveness, while 
at the latter both the straw and heads would be of a more slender and feeble growth. 
There would seem to be few occasions where this method could be 
used, and I am confident that in the majority of the Western States it 
would be entirely impracticable, as the presence of the fly is not mani- 
fest early enough in the season to permit of its adoption. 
SELECTION OF RESISTANT VARIETIES OF WHEAT. 
From early times there has been a recognition of the fact that cer- 
tain varieties of wheat were much less subject to injury than others. 
Considerable literature has accumulated concerning these ." fly-proof" 
varieties. The varieties possessing these qualities are such as have 
coarse and siliceous stems, enabling them to stand and not break over 
