164 EXPERIMENTAL FARMS 



5-6 EDWARD VII., A. 1906 



some of the older land were injured to the extent of 5 j>er cent or more These summer- 

 fallows on new land did not seem to be so bad.' — D. W. McIurdy. 



* Oct. 31, Cartwright, Man. — We have a little Hessian Fly here, but some miles 

 away further south it was very bad. I put a letter in the local paper, advising farmers 

 to burn straw even more liberally than they have been in the habit of doing.' — E. F. 

 Heath.; 



' Sept. 7, Wellwyn, Sask. — Hessian Fly has done great harm to the wheat crop here 

 this year.' — John Hislop. 



There seems to have been no uniformity of opinion as to the crop conditions which 

 attracted the females when they were laying eggs, some farmers stating that the heavy 

 crops on summer-fallowed land were worst attacked, while others claimed that exactly 

 the opposite was the case. The following letter from Mr. L. E. Marmont, who has 

 made a study of insects and their habits is of interest : — 



' Nov. 28, Rounthwaite, Man. — I regret to say that the damage in this neighbour- 

 hood from Hessian Fly during the past summer was the worst since 1902'. On summer- 

 fallows, where the wheat was heaviest, there were so many broken down straws that it 

 interfered with the proper working of the binder. Cutting had to be done so low down 

 to get the bent over stuff, that it resulted in long ragged sheaves and an amount of 

 Btraw which made an appreciable difference in tlie time taken in threshing. I examined 

 straws in many fields and found from three to five flax-seeds at a joint. Many of these, 

 I found, were very light and apparently dead. We had some extremely warm days dur- 

 ing harvest, and this may have affected some of them. The wheat itself in injured 

 stems was almost as plump as the unaffected; so, we cut as low as possible so as to get 

 it. I have urged all my neighbours to try and bum their stubble, if possible ; but the 

 fall has not been very favourable in this way, still a good deal has been burned over, 

 and, if the spring is dry, more will be done then. Threshing was so slow and the ground 

 was frozen up so early that the area of fall ploughing is the smallest ever known ; con- 

 sequently, little has been done in this way against the fly, and I fear we shall have a 

 repetition of the spring damage to the young wheat, such as we had in the spring of 

 1903, unless the stubble is burnt over or turned down early. I think that from three 

 to five bushels per acre would be a conservative estimate of the damage round here.' 



'Dec. 8. — My son and I think that in Blyth and the surrounding district, the 

 damage, to wheat from the Hessian Fly would be about five per cent. The early sown 

 grain would be less and the late a little more.' — G. S. Charleson. 



The Location of the Injury. — The larvae of the Hessian Fly attack the stems of 

 wiheat, barley and rye, either in the root shoots of fall-sown grain, in autumn as well 

 as in spring, before the stems are formed or of spring grain in the root shoots ©r at 

 the second joint above the root. The minute red eggs are laid on the leaves by very 

 small gnats half the size of an ordinary mosquito, during June or soon after the young 

 plants appear above the ground. The appearance of the flies and the hatching of the 

 eggs are, however, very much influenced by weather conditions. Both of these may be 

 accelerated by warm damp weather, or the emergence may be delayed by dry cold 

 weather. After emerging, the mature flies pair at once, lay their eggs, and in a very 

 few days disappear. It is claimed that the Hessian Fly does not travel very far from 

 the field where it develops from the puparia or flax-seeds. This is an important point, 

 indicating the necessity of treating fields which are known to have been infested to a 

 certain extent. As soon as the little maggots hatch from the eggs, they work their way 

 down to the base of the leaf sheaths and attack the young stem at its junction with the 

 leaf. Frequently the stem is prevented from forming and the shoot is destroyed; but 

 a very few days' delay in the time of the laying of the eggs or of the hatching of the 

 larvae, enables the stem to begin to shoot up; and, when this takes place, they nearly 

 always develop and form an ear. In this latter case, the injury is of course much less 

 than when the shoot is destroyed. The larvae lie at the base of the leaf and attack the 

 succulent tender straw just above the joint, sucking the sap and gradually forming a 



