806 
Journal of Agricultural Research 
Vol. XXVIII, No. 8 
In some of the Upland fields the behavior of the affected plants is much more 
abnormal than with Pima. The size of the plants is notably restricted by the 
shortening of the internodes, and the leaves are dwarfed and distorted, as shown 
in Plates 10 and 11. Such deformities of the leaves apparently do not occur in 
Pima cotton, but are quite similar to the effects of the stenosis disease on Up¬ 
land cotton in Haiti. That the same disorder might produce different symptoms, 
or that differences of susceptibility might be shown in the various types of cot¬ 
ton, had also been learned from the previous study of the cotton disorders in 
Haiti and in China. Hence it was possible to suppose that the same disease could 
be responsible for the abnormalities of the Upland varieties, as well as of Pima. 
The leaf injuries of Upland cotton in China were less than those of Upland 
cotton in Haiti, but in both cases the Upland cotton suffered worse than the Sea 
Island. Pima cotton in China showed relatively little of the mosaic discoloration, 
and the leaves were not crumpled nor the internodes shortened as in the native 
Chinese varieties. But the Pima cotton in China lost most of its leaves from 
black-arm, as though the susceptibility to that bacterial disease had been in¬ 
creased by the growth disorder. The cotton that suffered worst from the growth 
disorder in China was the native Asiatic type, although an Indian variety of the 
Asiatic type with hairy leaves and stems appeared to be quite immune to the 
cyrtosis disorder (PI. 8). Similar differences of susceptibility to growth dis¬ 
orders or mosaic diseases are known in other plants. Although the crazy-top 
disorder does not show the usual symptoms of a mosaic disease, since there is no 
definite discoloration of the leaves and relatively little distortion, other features 
are closely parallel. 
OTHER GROWTH DISORDERS OF COTTON TO BE DISTINGUISHED 
FROM CRAZY-TOP 
Since the present interpretation of crazy-top would not have been reached 
without a previous study of other growth disorders, a review of such informa¬ 
tion seems necessary to give a clear understanding of the distinctive features of 
crazy-top. In addition to the disorders studied in China and in Haiti, to which 
reference has been made, the symptoms of crazy-top may be confused with 
other disorders which are of common occurrence in the United States, as brachysm, 
tomosis, and hybosis. Two or more disorders often appear concurrently in the 
same plant, and to some extent one disorder may be induced or intensified by 
another, so that the symptoms are variously combined. 
These maladies are described as disorders, rather than as diseases, because 
they are not of the same nature as the better known parasitic diseases of plants, 
caused by fungi or bacteria. Some of the disorders appear to be of the same 
nature as the so-called mosaic diseases of other plants which in some cases are 
known to be communicated by insects. Patch-work mottling of the leaf tissues 
with areas of darker and lighter green is a prominent feature in the cotton dis¬ 
order of China, but does not appear in crazy-top. 
BRACHYSM, OR CLUSTERING 
The name brachysm has been applied to an abnormal shortening of the inter¬ 
nodes of the fruiting branches of frequent occurrence in Upland cotton, and 
usually accompanied by malformations of the sockets where the pedicels of the 
bolls are inserted on the internodes of the branches. Instead of a separable 
joint between the pedicel and the internode there is a more or less complete 
fusion. Hence in brachytic varieties the abortive buds or young bolls are not 
shed, but remain attached to the plant, even after they become shriveled and 
