May 24, 1924 
Acromania , or “ Crazy-Top” 
813 
only the general feature that the growth of the plants is changed and becomes 
abnormal, yet this apparently is a sufficient reason why the different disorders 
should be associated at least for purposes of study. 
CRAZY-TOP SYMPTOMS COMPARED 
EFFECTS UPON THE SIZE OF THE PLANTS 
The dwarfing effects upon the internodes, petioles, and leaf blades are less 
pronounced in crazy-top than in cyrtosis or stenosis, and the foliage retains a 
healthy green color to the end of the season. In Pima cotton the size of the 
plants is but little affected, except that the crazy-top plants often grow a few inches 
taller than the adjacent normal plants, as though sterility had given the affected 
plants a greater vegetative vigor. The appearance of the upper part of crazy- 
top plants is like some sterile hybrids or like the rank growth of “ boll-weevil 
cotton ” when all of the buds are aborted through weevil attack. The impression 
of greater vigor in the crazy-top growth no doubt is increased by the resemblance 
of the upright abnormal branches to the normal vegetative branches which are 
produced from the lower nodes of the main stalk on rank-growing, widely spaced 
plants. 
In Upland cotton the effects of the disease may be much more pronounced, 
especially if the cultural conditions are not favorable for the plants or periods 
of stress are encountered. Near the center of the crazy-top spot, shown in 
Plate 1, some of the plants were quite stunted. This might result from earlier 
infestation of such plants when little of the normal growth had been formed, 
which no doubt would result in a greater restriction of later development. 
ABNORMAL BRANCHING 
The loss of the normal dimorphism of the branches, and the sterility of the 
affected plants are the most general as well as the most prominent feature of 
crazy-top. In Pima cotton the sterile crazy-top branches that replace the 
normal fruiting branches in the upper part of the plant are thicker and straighter 
than the normal fruiting branches and have an erect or ascending position 
instead of horizontal. Thus it could be said that formation of fruiting branches 
is suppressed by crazy-top, at least temporarily, during the period of stress or 
hot weather conditions. 
In normal plants the two types of branches, fruiting and vegetative, are 
distinct, with definite functions and positional relations. The axillary buds 
produce vegetative branches, while the normal fruiting branches develop from 
extra-axillary buds, which stand at the right or at the left of the axillary buds. 
The abnormal branches that replace the fruiting branches and give the crazy-top 
plants of Pima cotton their peculiar and characteristic appearance are of inter¬ 
mediate forms, as sometimes occur in abnormal variations, like the so-called 
“bull-stalks” of Sea Island cotton, or in degenerate hybrids. Plants with such 
abnormal branches, intermediate between the vegetative and fruiting type, are 
often completely sterile, as a result of abortion of all of the flower-buds, usually 
at very early stages. Abortion of young fruiting branches was observed at 
Bard, Calif., several years ago and was considered an effect of over-luxuriant 
growth of the plants (3). 
If growth continues on the lower fruiting branches of affected plants, abnor¬ 
malities appear, like those of the top-growth. In some cases vegetative shoots 
are developed from axillary buds of the fruiting branch. In other cases the 
terminal portion of the fruiting branch changes its behavior, assuming the 
appearance of a vegetative shoot, and taking a more upright position, if the 
