[26] EEPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
There are many theories with reference to the cause of cotton blight, some attributing 
it to a fungoid growth, others to a peculiar poison in the soil, and still others to the 
work of insects. This last-named theory carried it to the attention of the Commission, 
and led me to make a careful study of the phenomenon. On taking up the plants, 
even at the first indication of wilting, I found all the rootlets completely dead and 
usually rotted, and the main or tap root dead, with the bark ready to slip off and the 
pith blackened. I found numbers of adjacent plants, showing no sign of blight above 
ground, that were more or less affected in the roots. In a majority of these cases 
many of the rootlets were already dead and decaying, while the disease had not yet 
reached the main root. Ia some instances half the main root was dead, while the 
other half, with its attached rootlets, was living and performing its natural func- 
tions. To some of these I carefully returned the soil without particular disturbance, 
not having unearthed the rootlets beyond an inch from the mam root, and not having 
unearthed the side of the main root more than three or four inches below the surface. 
In no such cases did the plants recover ; they all died a few days later, and an imme- 
diate examination revealed the fact that in the space of time named the rot had ex- 
tended to the healthy side of the root and rootlets. I further found that the first 
attack was made on the very extremities of the rootlets farthest from the main root, 
and usually on those deep down in the ground. From these extremities it passed 
gradually to the main root. When it had reached and surrounded the latter the 
leaves of the plant invariably wilted, as already mentioned. I saw not a single in- 
stance of the recovery of a plant after the leaves had begun to wilt from the effect 
of this blight. 
A most thorough study of cotton blight, made from time to time throughout the 
season, has entirely convinced me that insects have nothing to do with it whatever. 
This, of course, if I am correct (and 1 think I am), places it outside the scope of the 
United States Entomological Commission. I found no insects associated with it in 
any way that could be considered so much as even slightly suspicious. Nothing un- 
usual was ever found upon the plant above ground, and the insects found in the large 
quantities of earth that I examined, as taken from about the affected roots, were also 
found in equal numbers about the roots of healthy plants in portions of the fields 
where no blight had ever appeared. The microscope revealed to me a fungoid growth 
upon the decaying roots and rootlets, but I was not able to make sure that this was 
otherwise than the result rather than the cause of the blight. I found the same fun- 
gus upon other decaying vegetation, while I could detect no trace of it on cotton 
roots in health, nor even in their earliest stages of blight. 
I trust 1 shall be excused if I here venture a step beyond what I consider the prov- 
ince of the Commission to state that cotton blight, once started, appears in succeed- 
ing years upon the same spots ; usually upon the highest and best drained lands of 
the field. I was often told that any other crop than cotton planted upon the same 
spots would be likewise blighted, but this I subsequently found to be a mistake. 
Rotation for a few years in other kinds of crops destroys it, so that when cotton comes 
back to the same field blight is not apt to appear for a year or so at least ; and when 
it does appear there is no certainty that it will appear in the old spots. This points 
to the fact that it is something peculiar to cotton, and to the further fact that, be the 
cause what it may, rotation of crops is the remedy. 
BOLL ROT. 
This is another phenomenon which has been greatly puzzling the cotton-planter 
and his friends up to the present time, and giving rise, as such things usually do, to 
any number of theories. It consists in the rotting of the interior of the boll after it 
has attained nearly or quite to full size. In some cases the entire contents, both lint 
and seed, become a fermented and putrid mass, bursting the boll and running out 
frothing over the exterior, presenting a most disgusting spectacle. In other oases the 
contents of but one or two divisions in the boll go into putrefaction, leaving the re- 
mainder to mature and open out an inferior grade of cotton ; though this is the ex- 
ception rather than the rule. Usually when the rot takes hold of a boll all its con- 
tents are totally lost. 
The first indication of boll rot is abruised or greasy-looking circular spot about one- 
fourth of an inch in diameter on the outer covering of the boll. As this spot grows in 
age it changes gradually from its original dull green to a dark brown color, after 
which, if the boll has not already burst, as a result of internal fermentation, it will, 
if opened, be found to contain only the disagreeably-looking mass already described. 
If found already burst, an examination will be apt to show its interior literally work- 
ing with small worms, the larvae of insects that, attracted by the matter oozing from 
its ruptured seams, have made use of it as a nidus in which to hatch and rear their 
young. 
In times past these little worms, simply a result, and not at all connected with the 
cause, have been charged with the authorship of this boll rot mischief, but I had the 
