May 24, 1924 
805 
Acromania, or u Crazy-Top'’ 
Although the differences between the normal growth and the crazy-top growth 
are usually less striking than in the disorders in foreign countries, in other respects 
there are close analogies. After a period of normal development early in the 
season, the plant characters are changed abruptly and all of the later growth not 
only is abnormal, but shows many kinds and degrees of abnormality. The 
diversity of the affected plants renders it more difficult, of course, to recognize the 
disease, especially in scattered individuals, but when the crazy-top plants occur 
in large groups or areas there seldom is any difficulty in distinguishing the normal 
from the abnormal individuals. 
One of the most general and striking features of crazy-top in Pima cotton in 
Arizona is the change in the form of the branches at the top of the plant, which 
suggested the name of the disorder. The upper branches of the affected plants 
usually are stronger and more upright than the normal horizontal fruiting 
branches developed from the lower joints of the same stalk (PI. 2). The 
abnormality may be considered as a suppression of fruiting branches, or as a 
partial transformation of fruiting branches into vegetative branches. The 
transformation usually is not complete, as shown by the presence of a small 
floral bud or bud-scar at each joint of an abnormal branch. Some of the plants 
abort their buds at very early stages, as indicated by ^ery small bud-scars, while 
other plants develop their buds nearly to the flowering stage before shedding. 
The abnormal branches also show frequent examples of fasciation or adhesion, 
where the branches divide but the bark remains united. 
The sterility of the crazy-top plants is the feature of most interest to the farmer. 
Not only the abnormal upper branches are sterile, but usually the whole pJant. 
(See PI. 2.) A general shedding of buds and young bolls is considered by S. H. 
Hastings as the first symptom of an outbreak of the disease. This would 
explain why the normally formed lower fruiting branches are so generally sterile 
on the crazy-top plants, though sometimes a few bolls are retained. The extent 
of shedding may depend upon the conditions at the time of infection, or the 
injury might not become apparent until stress conditions were encountered. 
Of course, the symptoms are more striking and the losses greater when the crazy- 
top plants are in large groups or areas. 
If there are no bolls to open, the crazy-top areas show notable contrasts with 
the other portions of a field at the end of the season. (See PI. 1.) Such contrasts 
are more striking in Upland cotton than in Pima because the Upland bolls are 
larger and the fiber is pure white, while the Pima bolls are smaller and more 
evenly distributed, and the fiber has a buff tinge. Also the affected plants of 
Pima are not so completely sterile, but usually produce at least a few bolls at the 
top of the plant late in the season. With favorable cultural conditions a few of 
the affected plants of Upland cotton may set bolls late in the season, though 
mostly very small and imperfect. 
CRAZY-TOP MORE SEVERE IN UPLAND COTTON 
In former years, when the Pima cotton was grown exclusively in the Salt River 
Valley, the crazy-top abnormality was considered by some as an indication that 
the variety was “running out,” and even urged as a reason for planting Upland 
varieties. But with Upland cotton planted extensively in 1923, and crazy-top 
appearing in many of the fields, that explanation of crazy-top could no longer 
be maintained, although many of the growers did not recognize the disease in 
Upland cotton on account of the different symptoms. 2 
2 In this connection it may be noted that the average yield per acre of Pima cotton in 1923 was the highest 
since the variety began to be grown commercially. Also a careful comparison of old and new seed stocks 
in 1922 gave no evidence to support the idea of running out. See Kearney, T. H. (1 %) . 3 
3 Reference is made by number (italic) to ‘‘Literature cited,” p. 827. 
