10 



the flowers of the middle crop are beginning to open. The 

 lower crop would have simply the wind to introduce the 

 disease, while the middle and top crop would have in 

 addition the greater agency,- insects. An effort will be made 

 this summer to determine whether or not the bacteria do 

 normally enter the bolls through the flower, and also to de- 

 termine the insects which carry the disease from one flower 

 to another. Experiments are now being conducted to de- 

 termine the truth of the other four supposed methods of 

 the distribution and entrance of the bacteria into the inte- 

 rior of the cotton-bolls. 



So far as my observations and experiments are concerned, 

 I have never been able to induce the rot bacteria to develop 

 the disease or cause pathological disturbances in any part 

 of the cotton plant other than the interior of the bolls* 

 although they will live and even multiply to a slight extent 

 within the tissues of the other parts of the plant. 



All the facts in the case go to show that the cotton plants 

 naturally become afiected either by the rot bacteria entering 

 the roots from the soil, or that the plants begin their ex- 

 istence as affected ones by the bacteria having entered the 

 cotyledons (seed leaves) of the seed while still within the 

 boll, or that the bacteria are carried by the wind or insects 

 from the soil to the flowers, and from one flower to another, 

 and enter the bolls in this way. It hardly seems probable 

 that the bacteria coald be blown by the wind or carried b}^ 

 other agencies upon the surface of the cotton-bolls and enter 

 by that route, since the rot disease always makes its first 

 appearance as a small diseased area of the seed and lint in- 

 side the boll near the petiole, and only later involves the 

 carpels, and makes itself apparent on the exterior. Never- 

 theless, the bacteria may enter in this way and migrate to 

 the seeds, for we have no definite proof to the contrary. 



The rot disease seems to be principally confined to the 

 middle and top crop, and makes itself manifest to the ordi- 

 nary observer about the first of August. It is usually pretty 

 evenly distributed over a field, and as yet is not as trouble- 

 some to river plantations as to high lands. That this rot 

 disease is a very important one can be seen from the fact 



