REPORT OF THE STATE ENTOMOLOGIST T.MIl 717 



3 Adults are killed by heavy frosts but this is not true of 

 larvae and " flaxseeds " or pupae and hence flies may appear 

 and deposit eggs heticeen killing frosts. 



4 Under certain conditions some of these insects may spend 

 nearly a year in the '' flaxseed " stage. 



The above rules show that egg-depositing flies may appear at 

 any time during the growing season, providing weather con- 

 ditions are favorable, though naturally we would expect them 

 to appear in great numbers only at the first favorable period 

 after a large brood had attained the " flaxseed " or pupal stage. 

 Thus, as our springs are usually warm and moist, this means 

 that ordinarily most of the " flaxseeds " will develop flies in the 

 latter part of April or early May. Then there must be a suffi- 

 cient period for the completion of a life cycle before another 

 brood of flies can appear and if at that time and for a consid- 

 erable period thereafter the weather be dry and hot, compara- 

 tively few or no flies will appear till conditions change and 

 consequently we can not tell just when flies will appear again. 



We do know, however, that early sown winter wheat is very 

 apt to become badly infested in the fall while late sown wheat 

 frequently escapes. In the first instance the young wheat is 

 up and receives a deposition of eggs before or between killing 

 frosts, while in the other case it escapes. Weather conditions 

 must always be considered in sowing winter wheat. The gen- 

 eral rule for the safe sowing of winter wheat may be stated 

 as follows: 



Moist warm weather in early fall will permit the safe sowing 

 of wheat at a relatively early date, but when the early fall is 

 dry, delay sowing till the latest possible date. The normal or 

 average date when wheat can be sown in New York without 

 danger of its becoming infested with the Hessian fiy is about 

 September 20. 



Effects of continued drtjness and moisture. Following is an 

 Interesting record by Dr Kiley: 



It has long been known that the Hessian fly flourishes best 

 when the chinch bug flourishes least; in other words, that wet 

 weather favors it. The prejudicial eit'ect of drouth has not 

 been hitherto observed, that we are aware of, but it was very 

 noticeable in parts of Ohio, where the puparia literally dried 

 up. Our attention was first called to the general death of the 



