May 24, 1924 
Acromanidj or u Crazy-Top” 
825 
determine whether the yields are reduced in Upland cotton to a greater extent 
than in Pima. 
Locating and mapping of crazy-top areas would be desirable, to determine 
whether the disease recurs regularly in the same places. Also such localizing of 
the disease might lead to the discovery of native plants or weeds that carry the 
disease through the winter and serve as reservoirs of infection. There are many 
wild Malvaceae in Arizona, and crazy-top might not be confined to a single 
species. A wider range of host-plants is indicated for mosaic disorders than for 
fungous or bacterial diseases. The sugar cane mosaic is communicable to 
grasses of other genera, and an inoculation of Nicandra physaloides with the potato 
mosaic has been reported recently (9) . 
Insect carriers of the crazy-top infection might also be identified, if the disease 
were traced to wild plants, and such knowledge might make it possible to control 
the disease by removing the source or preventing infestation. On the other hand, 
if the sources and agents of infection are neglected, the disease may increase 
through the establishment of more centers of infection among the wild plants. 
Over-wintering of crazy-top plants should be studied, to determine whether 
such plants survive and carry over the disease, whether the symptoms can be 
detected early in the season, and whether such plants are a factor in extending 
the disease. 8 
Fields that have had crazy-top injuries in previous years should be watched 
carefully to see if the beginning of the injury can be detected. It is believed by 
some observers that the onset of the disease is definitely indicated by the shed¬ 
ding of all of the squares and young bolls. Where abnormal shedding occurs 
with no apparent cause, the development of other crazy-top symptoms should 
be looked for, although it is possible that infestation may occur at earlier stages, 
and that the more striking symptoms are developed when stress conditions are 
encountered. 
Early infestation may be indicated by different habits of growth of the plants 
or more gradual development of the symptoms, without the very abrupt change 
that apparently marks the onset of the disease in previously normal individuals. 
The occurrence of large numbers of such plants, though without the usual crazy- 
top appearance, should be studied with reference to early-season infestation of 
crazy-top, which might render the growth more consistent, without the abrupt 
changes that result from infection at later stages of development. 
Cases of delayed recovery from the hybosis disorder have been noticed as 
occurring in groups or areas like crazy-top and possibly may be connected with 
early transfers of crazy-top infection from native vegetation by the plant lice. 
Also early infestation in Pima cotton may be indicated by plants of slender 
upright habit that often are completely sterile, although a few bolls may set late 
in the season. If early infections of crazy-top could be recognized and destroyed, 
protection might be secured against later spreading of the disease. Or if large 
areas are found to be affected, the cotton could be plowed up and the land used 
for other purposes. 
8 Persistence of the disease by over-wintering of affected plants was definitely shown in the Hartsville 
field at Casa Grande, visited May 27, 1924. The abnormalities of the new growth were as striking as those 
of the previous season, and appeared on many plants which had not shown the disease in the fall, along 
the margins of the affected area. In a field of Pima cotton near Scottsdale, visited May 29, the shoots of 
many plants also showed a definite reduction and cupping of the leaves, although the symptoms generally 
were much less pronounced than in the Hartsville field, and many of the Pima plants appeared normal. 
Crazy-top symptoms on seedling plants were first noted by C. J. King on June 11, 1924, in the Hartsville 
field adjacent to the diseased plants that had survived the winter. Since the field was being abandoned 
as unproductive, and was in a district well isolated from other cotton, Mr. King had arranged with the 
owner to try the experiment of over-wintering the diseased plants and of planting fresh seed in a part of 
the affected area. 
