oN. Tye 
N NOLS es 
45 
B. INJURIES TO THE ROOTS. 
_ Injury to the roots of corn in spring and early summer may be 
indicated to the close observer by the aspect of the growing crop. If 
the corn fails to appear in spring, the difficulty may not be due to poor 
seed or to injuries to the kernel, but may be caused by an early insect 
attack upon the young roots, which may even kill the plant outright 
before the sprout has broken ground. The root louse of the corn and 
the wireworms are most likely to be concerned in this form of injury. 
Later in the season, when the plant is a few inches high, the uneven 
growth of the corn will often attract attention, patches here and there 
advancing slowly in comparison with parts of the field adjacent, and 
in a way not to be accounted for by differences of soil. In such cases, 
white grubs, wireworms, corn root worms, or plant lice should be sought 
for. Combined with this uneven growth, or possibly in times of drouth 
without it, the farmer may notice yellow patches in his field, the color 
being most pronounced upon the lower leaves. ‘The root louse of the 
corn will be found responsible in most cases for this partial discoloration, 
but any of the species just mentioned may produce a similar effect,* 
or it may be caused on the lower part of the stalk by the chinch bug. 
An especially significant symptom of more or less serious mischief 
is the presence in the field of numerous burrows of ants, commonly 
placed in or immediately near the hills of corn, and most conspicuous 
shortly after rains. This invariably indicates the presence of root lice 
in the field, although if the corn be small a careful search may fail to 
detect them at the time. The nature of the association between the ants 
and the root lice is such that the former prepare the way for the latter 
early in the season by sinking their burrows among the corn roots, thus 
giving the lice access to them. ; 
If at about the time the ear is beginning to form, and from that 
time onward, the stalks of corn are easily prostrated by wind and rain, 
and do not readily rise again, it will commonly be found that the hold 
of the plant upon the earth is abnormally slight, so that the hill may be 
pulled up too easily. This condition of the plant is due to a loss of 
roots, usually to be attributed to one of the corn root worms, or, more 
* A condition of the corn very similar to that just described is not due to insect 
attack at all, but to a bacterial disease of the roots known as the corn root blight, 
fully described by Prof. T. J. Burrill in Bulletin No. 6 of the Illinois Agricultural 
Experiment Station (August, 1889). In this disease the corn stops growing in 
patches, becoming yellow and usually slender, and sometimes dying while young. 
The yellow color is most pronounced upon the lowest leaves. On pulling up the 
plant, the oldest and the lowest roots are seen to be injured and usually dead, the 
bottom part of the stalk to which these roots are attached being similarly affected. 
If split through the middle, the inner tissue of this lower part is seen to be of a 
uniform darker color, and a slight discoloration, becoming less and less pronounced 
above, appears in the next succeeding joints, while the parts between them are 
seemingly healthy. On the surface, when carefully cleared of dirt, brownish cor- 
roded spots may be found, sometimes covered with a firm gelatinous material. 
