36 



H.-Sch., are known to occur on cotton plants and puncture the squares 

 and bolls more or less, but ordinaril3% according to our observations, 

 these species are not the occasion of much injury. Much more 

 important, howev^er, is the shedding of squares and young bolls, or 

 their drjdng up on the plant, which is in no way the result of insect 

 attack, but is a physiological trouble. Injury of this character has 

 often been pointed out as due to boll worms, and, on the whole, it is 

 not ordinarily distinguished b}^ planters from the work of this insect. 

 Interesting observations on this trouble were made b}^ Dr. G. F. 

 Atkinson when biologist of the Alabama Agricultural Experiment 

 Station, and reported in Bulletin No. 41 of that station. The impor- 

 tance of the subject warrants the presentation from that publication 

 of certain remarks which throw light on the character of the malady: 



The shedding of bolls or "forms," or their death and drying while still attached 

 to the plant, is very frequently a source of greatloss to the cotton crop. The trouble 

 has been long known, but one widely prevalent and disastrous form has been mis- 

 understood. It is often confused w^ith the work of the bollworm, with punctures 

 made by some hemipterous insect, etc. That some of the shedding is due to the 

 work of the bollworm is true, but the shedding referred to here is a purely physio- 

 logical trouble. 



During three years' observation in Alabama the author found this physiological 

 form of shedding to be very serious. It occurs most frequently in extremes of either 

 dry or wet weather, or during the change from one extreme to another. It may 

 occur to some extent under normal climatic conditions, especially if the cotton plants 

 are too thick, or the variety of cotton is one which develops a very large amount of 

 fruit forms in proportion to the leaf surface. 



During a normal period of growth the plants put out as many fruit forms as could 

 be matured should the conditions favorable to growth continue. If a very dry 

 period succeeds this, interfering with the supply of nutriment and moisture, there 

 will occur a partial withholding of tissue-forming material and moisture at a very 

 critical period in the life of the young "forms," and the tissues of the young fruit 

 are forced into an unnaturally matured condition. The fruit, including the pedun- 

 cle and often more or less of the surface tissue of the stem at its point of attachment, 

 becomes first of a paler green color than the adjacent parts of the plant, so that a 

 well-marked color line delimits the healthy from the unhealthy portion. In many 

 cases the tissue is separated at this line, so that the fruit falls off completely or hangs 

 by a few fibers to the stem. The early growing season may be exceptionally favor- 

 able for the development of a large plant with an abundance of young fruit, and if 

 followed by even ordinarily normal conditions will result in a partial loss of this 

 fruit. A long rainy season may also cause the young bolls or forms to fall, the soil 

 being so saturated with water as to interfere with root absorption, and the assimila- 

 tive activity of the leaves will also be disturbed. 



Observations have been made at different times bearing on the 

 amount of injury from the bollworm as compared with that from other 

 causes. The following table made up from observations by Mr. C. R. 

 Jones indicates the character of results in general. Squares were 

 picked at random from the cotton plants in passing through the fields, 

 and afterward examined and classified. Five hundred squares were 

 picked from each field. 



