31 
Under specially unfavorable circumstances, the loss due to the in- 
sect may amount to from one-fourth to one-half or even three-fourths 
of the crop, but when the conditions are generally favorable, it rarely 
amounts to more than ten or twenty per cent., and frequently even 
to less. Although the roots penetrated by the larvee die and decay, 
thrifty corn will throw out new ones to replace those lost, and this 
is most likely to occur in moist, rich ground and in wet seasons. 
The damage is therefore greatest on high ground and in dry weather, 
and the use of manure will palliate, but not wholly obviate the 
Injury. 
No natural enemy of this insect has yet been discovered, nor is 
anything known to indicate that changes of the weather have any 
serious effect upon it. 
As the results of numerous observations and comparisons, it is 
plain that little or no mischief is done except in fields that have 
been in corn during the year or two preceding, and a frequent 
change of crops is therefore a complete preventive. Beyond this the 
life history of the insect gives us little present hope of fighting it 
effectively, except at too great expense, as the eggs and worms are 
scattered and hidden in the ground, and the perfect beetle is widely 
dispersed throughout the field. Kxperiments will be instituted at 
the earliest possible day with a view to determining whether some 
fertilizer whose value to the crop will pay for its use may not have 
a destructive effect either upon the egg or the larva in the ground, but 
until such experiments are made and verified, intelligent rotation of 
crops must remain our sole effective resource against this most 
threatening and destructive insect. 
