June, ’23 
dean: hessian fly control 
289 
because no definite conclusion had been reached as to the carry-over 
places or the source of the reinfestations. For a number of years it was 
thought that few Hessian flies remained throughout the wheat fields, 
and with favorable climatic conditions here they increased until there 
were sufficient numbers to cause serious damage or an outbreak which 
might extend over only two or three counties, or over the greater part 
of the entire wheat belt. However, in certain seasons, careful surveys 
and thorough examination of wheat plants failed to reveal any stage 
of the fly in the majority of the fields, and in fields where the fly was 
found it was usually in some isolated spot in the field, or some local area 
extending over a number of fields. 
Observations and surveys extending over a period of twelve years 
have shown that the fly, during the years when there were no appreci¬ 
able injuries, instead of living over in very limited numbers throughout 
the wheat fields, survived and bred in local areas that might be termed 
“reservoirs” or “carry-over areas.” In general, these “reservoirs” 
consist of low, moist, springy places with a heavy soil. With the ex¬ 
ception of the. southeast portion of the state which has a considerable 
portion of low, swampy land, with a heavy soil and heavy rainfall, 
these infested areas usually consist of only an acre of two, although in 
several cases they may extend over an entire field of from 40 to 80 acres, 
and in a few instances they may consist of several square miles. 
For instance, on the north side of Mill Creek in Wabaunsee County, 
there is an area about one mile wide and five miles long in which the 
Hessian fly has been found every year since 1911, and the farmers claim 
it had caused serious losses for several years previously. A control 
campaign was inaugurated on two farms in this district in 1913 with 
such good results that in 1914 the campaign was general over the entire 
area and the fly was brought under control. 
However, the fly has been able to persist in this area and whenever 
wheat was sown early or volunteer wheat was allowed to grow, it be¬ 
came abundant. A survey of this area in November, 1921, failed to 
show any fly except in one field where a few acres had been planted 
early. This same area was visited again Sept. 29, 1922, and the Hessian 
fly eggs were so numerous on all volunteer wheat throughout the entire 
strip that it was necessary to destroy all the volunteer before planting. 
About six miles west of McPherson there is a large area, locally known 
as “the basin,” which is an old lake bed with very poor drainage. Our 
records show that fly has been found in this area practically every year 
since 1908. Again, southwest of Salina there is an area consisting of 
