4 INSECTS INJURIOUS IN 1902. 
fact that its presence is not revealed to them until the injury has 
been done and the grain is down, and from the further fact that 
a large number of our farmers are unfamiliar with its work and 
have been accounting for the falling grain as the result of hail. 
In fact, I am creditably informed that some sought and obtained 
hail insurance for grain injured by the Hessian Fly. It is weil 
worth noting that although it is generally on the increase ana 
bids fair to cause much greater injury in the future, its increase 
like that of many anoiher pest is marked by periods of decrease. 
It is wave-like, if I may use that expression, for as its numbers 
expand favorable conditions are created for parasites which infest 
it, causing them to increase in enormous numbers and temporarily 
get the upper hand. But their victory is necessarily of short dura- 
tion and only leads to their own destruction for as they destroy 
their food supply their own numbers decrease, and again their 
host, the Hessian Fly, takes another bound forward, for the time 
at least not much hampered by parasites. Although the parasites 
of the Hessian Fly are largely common in all localities of the state 
where the fly is found, the writer having noted their presence in 
many specimens secured from different points, the farmer cannot 
afford to neglect certain preventive measures which lie ready at 
hand in keeping down the pest which bids fair to very materially 
reduce our output of wheat. In mentioning these measures I wish 
as a preliminary to state that the individual farmer must use his 
judgment in their application. He should be guided by the pe- 
culiar conditions of his surroundings, conditions which might not 
occur in the case of another farmer. 
1. Burn the stubble when possible. This is particularly desira- 
ble when, from any reason, shallow plowing is unavoidable. If 
the stubble is left long it will burn easier. Some farmers are 
willing to go to the trouble of spreading straw from threshing 
over the stubble, thus insuring the burning and at the same time 
getting rid of some “flax seeds” which may have lodged on the 
surface of the straw pile at the time of threshing. 
2. Fall plowing of the stubble in such a way that tlie straw is 
completely turned under. 
3. All screenings and litter about the threshing machine should 
be cleaned up and either fed immediately or burned, leaving no 
