May 24, 1924 
Acromania , or “ Crazy-Top” 
817 
water and the normal foliage below the crazy-top growth revived completely 
and remained fresh for several days. 
If any difference in color is to be detected, the foliage of the crazy-top plants 
appears to be darker or to hold its green color late in the season. The darker 
foliage could be considered as a result of sterility, rather than as a character 
of the disease, but confirms the absence of any mosaic effect. If a color difference 
had been shown the disease undoubtedly would have been considered as a mosaic 
as soon as its existence was recognized. 
SHEDDING OF FLORAL BUDS 
Abortion of the floral buds or “ squares” is a feature of crazy-top, as of cyrtosis 
and stenosis, with the extent of abortion and the stage at which it occurs depend¬ 
ing very largely upon the external conditions and also showing a wide range of 
individual variation among neighboring plants when the critical conditions are 
approached. All stages of sterility may be shown, from plants that shed all of 
their floral buds at very early stages through those that retain their buds to 
larger sizes, with some that produce flowers but fail to set any bolls and others 
that set bolls, but still differ in numbers and degrees of development attained. 
Even at the end of the season when most of the plants are showing more normal 
behavior some individuals may remain completely sterile and fail to develop any 
of their squares beyond the microscopic or scarcely visible sizes. (See PI. 12.) 
ABNORMAL INVOLUCRES 
Some of the crazy-top plants have very small involucral bracts, even on the 
buds that are retained to the stages of flowering and fruiting (PI. 14). The 
marginal teeth of the bracts may be very small, or very irregular in size, or 
deeply split into three lobes, as in the abnormal involucres that are of frequent 
occurrence in brachytic varieties, representing intermediate stages between 
bracts and leaves. Some of the reduced bracts of crazy-top plants have only three 
teeth, like the small involucres of Thurberia thespesioidesj a plant related to 
cotton, growing wild in the mountains of Arizona. 
Involucres formed of a single empty bract, resulting from abortion of flower- 
buds at very early stages, occur frequently on the crazy-top growth of Pima and 
Acala cotton. Similar sterile involucres were abundant in weevil-infested fields 
at San Antonio, Tex., in 1921 (7). The production of such involucres was con¬ 
sidered as an abnormal condition that might be due to persistent pruning of the 
floral buds by boll weevils, though it now seems possible that a growth disorder 
might be involved, in addition to weevil pruning. Other indications of a growth 
disorder in south Texas are reported in a recent letter from B. V. Hasselfield.® 
• An extensive shedding of small squares at the U. S. Experiment Farm, San Antonio, Tex., is also 
reported by Robert D. Martin under date of June 19, 1924, with specimens of an insect that has been 
identified by the Bureau of Entomology as Psallus seriatus Reuter, the so-called “cotton flea." Most 
of the squares were being shed at very early stages of development, between 1 and 5 mm. in diameter, so 
that relatively few buds reached the stage of being infested by the boll weevil. 
The popular belief in the relation of the “flea" to the shedding of the squares has been questioned because 
the insects are found where the severe shedding does not occur, and because shedding has continued where 
the insects have been kept away from the plants by cages. But, with a growth disorder, shedding would 
continue without the insects, or the disease might be absent while the insects were present. A disease 
conveyed by the “fleas" or other insects is indicated by the continued shedding of the young buds and 
the formation of many ablastic involucres, as observed at San Antonio in 1921; but the striking deforma¬ 
tions of the leaves and branches produced in Upland cotton by the crazy-top disorder in Arizona apparently 
do not occur in Texas. For a disorder manifested chiefly by the shedding of the squares, ablasty, or square- 
drop, would be an appropriate name. More frequent over-wintering of infected cotton plants or native 
malvaceous weeds might explain the restriction of the disease to southern Texas, although the insect is 
more widely distributed. Such a disease may be preventable if the source of infection can be determined. 
