April, ’24] 
larrimer: hessian fly statistics 
205 
Some effort has also been made to develop a method to be used after 
harvest to estimate with some fair degree of reliability the total amount 
of damage that can be charged up to Hessian fly. For instance, the 
estimated number of acres of wheat sown in the state of Indiana in the 
fall of 1919 was 1,960,000. Of this amount 225,000 acres were estimated 
to have been abandoned in the spring of 1920 because of infestation by 
Hessian fly the previous fall. From the acreage left standing, the yield 
was estimated at 7,280,000 bushels less than would have been pro¬ 
duced by a'ten year average yield. Considering this deficiency due to 
Hessian fly and computing the probable yield of the abandoned acreage 
on the basis of the ten year average yield, a total loss of 11,260,000 
bushels could be estimated. 
As a contrast to this scheme of estimation there is the well authen¬ 
ticated case pf a similar estimate being made in a mid-western state 
where the task was assigned to a farm director and two agronomists. 
Each of the three made up his mind off hand and independently. The 
average thus obtained was considered too large and after considerable 
discussion it was cut exactly in half. This final result actually appears 
in the publications of that state as an unqualified statement of a definite 
amount of damage caused by Hessian fly. 
This second case need not be further considered except to express the 
opinion that such estimates are far too frequently made. Without 
going into details in discussing the first case, the many non-compensating 
and irregular factors other than Hessian fly infestation that enter into 
the final yield of wheat should be considered. The effect of variation of 
soil and seasonal conditions is exceedingly important. Joint worm is 
some years worse in early and other years worse in late sown wheat. 
The greater wheat stem maggot is evaded by delayed sowing much 
the same as Hessian fly. Leaf rust is usually worse in the fall on early 
sown wheat and in spring on the later sowings, but this factor is far 
from constant from year to year. The observance of advised seeding 
dates varies in different parts of the country and in the same section 
from year to year. All of these, interrelated factors, together with 
many more which could be mentioned, certainly emphasize the extent of 
the unreliability of any such estimates of the amount of damage by 
Hessian fly. Have not such estimates in the past been largely figures 
based originally on an opinion rather than an opinion based on figures? 
It might be pertinent to inquire as to the fundamental purpose which it 
is intended that such estimates should serve and whether or not this 
