42 THE HESSIAN FLY IN THE UNITED STATES. 
In fact, we Lave the authority of Professor Webster for the statement 
that the Hessian fly need be no longer a source of loss under a proper 
system of agriculture. That the farmer, however, be best prepared to 
contend with the insect involves for him a thorough knowledge of the 
conditions favoring or obstructing the action of the insect, and to this 
end he should be jwrticularly familiar with the conditions of accelera- 
tion or retardation of development as affecting the time of appearance 
of the various broods. 
Probably the most important measures available with our present 
knowledge are those directed against the insect in its summer resting 
period or the early issuing flies of late summer and early autumn. 
BURNING THE STUBBLE. 
This remedy has been one of the standard measures from very early 
times, and while objection has been raised to it on account of the fact 
that the parasites will be destroyed along with the Hessian fly, it may 
be considered as one of the most generally applicable. To be effective, 
the burning must be performed before the flies have had an opportu- 
nity to emerge, but in this respect there is little danger of being too 
tardy unless unusual moisture accelerates the emergence of the flies. 
Postponement until the parasites have had an opportunity to emerge 
would, in fact, be an advantage, and, during dry weather in July and 
August, the firing may be postponed. In some cases the burning is 
made more effective by cutting the wheat pretty high, so as to leave a 
larger amount of stubble, thus insuring a more rapid spread of the 
fire. It has the further advantage of leaving with the stubble any 
chance " flaxseeds" which may occur higher up on the stalk than the 
usual position. 
An objection to burning, which has been suggested by Lindemann, 
and is supported by Marchal, is that under a given climate it may be 
that at the time of harvest a considerable part of the puparia will have 
already matured and the flies issued, so that those destroyed will be 
simply an insignificant part that have been delayed in their develop- 
ment, and their destruction, while useful, would be so in but a slight 
degree. The determination of the condition of the "flaxseeds" would 
be difficult except by examination by an expert entomologist, and 
treatment with reference to this point is rather impracticable. So far 
as the American wheat grower is concerned, it would seem unwise to 
use this objection, as the benefit in general from burning infested stub- 
ble is so great that other considerations maybe overlooked. The main 
point is to determine the time of movement, and this in general should 
be as soon after harvest as the conditions of the season are likely to 
cause the emergence of flies. 
Along with the burning of the stubble we may call attention to the 
desirability of burning chaff and screenings after threshing, as Miss 
Ormerod has pointed out that many puparia are to be found in these 
