56 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
harvest. As a matter of fact, in the case of the sawfly, grain from in¬ 
fested heads may be actually heavier in weight than grain from unin¬ 
fested heads. The great loss in the spring wheat country from such 
insects is occasioned by the falling of the grain to the ground before 
harvest. 
Insect Damage Confused With That of Hail 
Damage by the two insects just named may be mistaken for that of 
hail. On numerous occasions certain of my students who have spent 
summer vacations adjusting hail insurance have told me of claims put in 
by farmers for losses by reason of hail, which were in fact due to injury 
by the Hessian fly. The insect factor in adjusting hail losses has been 
considered of such importance that a little booklet 1 has been recently 
issued indicating means of recognizing injuries caused by various in¬ 
sects and plant diseases, which may be confused with that of hail. 
Temperature 
That temperature is an important factor in insect damage is well 
known. Injury to planted corn by the seed corn maggot is more pro¬ 
nounced during cool springs, when the seed remains in the ground for 
some little time before germinating. On the other hand, temperatures 
ranging higher than normal serve to accelerate the rate of develop¬ 
ment of insects, and consequently tend to increase the severity of their 
damage. This would be less important in the case of soil inhabiting 
insects, the rate of development of which would be regulated more by 
the temperature of the soil than by that of the air above. 
Moisture 
As deficient moisture is the most important cause for losses to wheat, it 
is also a very important factor in increasing the severity of insect losses 
to crops in general. It is obvious that plants, the growth of which 
have been retarded primarily because of lack of moisture, will suffer 
more insect damage than other plants that have not been so retarded. 
Because of a lesser amount of leaf surface, or total green weight avail¬ 
able as food for destructive insects, the whole amount of damage will 
be more severe than under conditions where a sufficient amount of 
moisture for plant growth has been available. With an equal number 
of insects attacking it for each square rod or square mile, the crop 
growing under conditions of deficient moisture is bound to suffer insect 
Tosses to Grain and Cotton. Hail Department. Western Adjustment and 
Inspection Company. (1919?) 
