182 



THE AGRICULTURAL NEWS. 



June 3, 1916. 



COTTON CONFERENCE. 



THIRD DAY'S PROCEEDINGS. 



(Concluded.) 

 Pests ajji) Diseases of Cotton, and Tiu'.ik Conti'.ol. 

 In opening the discussion on this subject, the President 

 said he thought that previous discussion had shown that 

 cotton is not tlireatencd with aiiy general epidemic which 

 is likely to be disastrous to the cotton industry as a whole. 

 There were, however, diseases which required careful consid- 

 eration. Before proceeding to consider West Indian pests 

 and diseases, the President thought it would bo stimulating 

 if Mr. Ballou, the Entomologist to the Department, gave 

 a brief account of the Mexican boll weevil and its spread in 

 the United States. This pest was a menace to the American 

 Sea Island cotton industrj", and its steady, spread and the 

 campaign against its spread presented features of great 

 interest. 



Mr. Ballou then gave first, a short historial account of 

 the spread of tlie boll weevil from Southern Texas north- 

 wards. It was discovered in Southern Texas in 1892. The 

 Government failed to' declare a quarantine line, and since 

 1892 the pest has spread year by year through the cotton- 

 growing areas of the Southern States, doing enormous damage. 

 Every time the pest has struck a new area it has reduced the 

 output of cotton in that area about .50 per cent. A remark- 

 able feature is that, of recent years, the yield of cotton per 

 acre in the infested areas has gone up, due to the introduction 

 of better systems of cultivation — changes necessitated by the 

 pest with a view to its control. Mr. Ballou then indicated 

 on the map the progress of the spread of the boll weevil 

 from Texas to Oklahoma and Arkansas, Louisiana, Mississippi, 

 Alabama, Western Florida and Georgia, with the certain 

 prospect of its proceeding on to South Carolina. !Mr. Ballou 

 estimated that it would not be later than 1922 before the 

 American Sea Islands which are just oft' the coast of South 

 Carolina would be infested by the boll weevil, resulting in the 

 disappearance of the American Sea Island cotton industry. 

 In conclusion, Mr. Ballou pointed out the grave responsibility 

 which would rest upon anyone importing material from 

 America likely to carry the pest, though as a matter of fact, 

 there was some reason to believe that in these islands the 

 boll weevil might not assume such serious pro])ortions as it 

 did in the Southern States. 



The President in remarking on Mr. Ballou's observations, 

 said that the control of the boll weevil by changes in 

 methods of cultivation was on a smaller scale paralleled by 

 the planting of cotton in Antigua at a certain period to 

 avoid the tloweif-bud maggot. The President thena.sked 

 Mr. Nowell, the Mycologist of the Department, to make 

 a statement concerning the internal boll disease of 

 cotton — a serious affection which is very widely spread 

 throughout the AVe.st Indies, the importance of which has 

 only recently been realized. 



ilr. Nowell said that this boll disease hafl been recog- 

 nized in Montserrat for many years, but its exact cause had 

 not been definitely cleared up. The unique feature about 

 the internal boll disease was that the bolls appear on the 

 ontside perfectly healthy, even up to the stage when they 

 ought to be opening and showing their ripe cotton; but 

 within, in the later stages, one or more locks of the boll 

 contain only rotting material. Such a condition was difficult 

 to account for, as boll diseases generally start from the 

 outside and spread from the wall of the boll to the cott :)n 

 ■within. It was first suggested by Mr. Uobson that there 

 ■was some connexion between the disease and the occurrence 



of cotton stainers. The experiments which had since been 

 carried out proved that there is a necessary connexion 

 between cotton bugs and internal boll disease. This had 

 been demonstrated by both Mr. Kobson in ilontserrat, and 

 Mr. Harland in St. Vincent. Mr. Nowell went on to say 

 that the disease and its transmission were of very great 

 si'ientific interest. In nearly all ca.scs examined by him 

 there was present ;t particular fungus with very peculiar 

 and distinct characters, though in some cases bacteria only 

 were found to be present. The present information was, 

 he said, that the disease was always associated with the 

 fungus or with b-icteria, and that the disease does not occur 

 unle.ss there have been cotton stainers or other bugs sucking 

 from the outside. The exact way in which the organism 

 obtains access was not yet definitely known, but it was 

 jirobable that it is carried by the cotton stainer. From 

 a practical point of view, the control of the disease was 

 obviously bound up in the control of plant-feeding bugs, 

 especially of the cotton stainer: no bugs, no internal boll 

 disease. Mr. Nowell added that in l5arbados, where the 

 cotton stainer docs not occur, he had found internal boll 

 disease associated with the green bug. 



Mr. Ballou then proceeded to make a few remarks 

 concerning the cottoii stainer problem. He had to confess 

 that the control of cotton stainers was at present inadequate. 

 For a considerable time certain treatments - hand collection, 

 water and kerosene, spraying the young stainers early 

 in the season, putting down trap heaps — had been 

 tried with a certain amount of success, but something 

 more was necessary "before there could be anything like 

 .satisfactory control. With regard to the lifc-hi.-itory of the 

 cotton stainer, Mr. Ballou said there was only one point it 

 respect of which there was some doubt, and that is the exact 

 place, under natural conditions, where the female lays her 

 eggs. The cotton st<iii er, Mr. Ballou said, was one of the 

 few groups of insects of which scarcely a single natural 

 enemy was known, but recently one had been reported from 

 Peru. As regards control, ^Ir Ballou thought that the 

 destruction of old cotton bushes, and particularly the des- 

 truction of the wild plants on which stainers feed when 

 there is no cotton were the most likely ways of keeping 

 down the pest. 



Considerable discussion then followed in connexion with 

 these last two points. Hon. U. L. Warneford (Antigua) said that 

 he had experienced sudden invasions of the cotton stainer, and 

 he believed that in hfs district they came from trees known as 

 Gamboge {Thcxpexin populnm) which grow on the seashore. 

 'Six. Maloney said that in Nevis after the cotton crop has 

 been gathered, stainers are seen on the physic nut tree. 

 Mr. K. P. Pencheou (Montserrat) said that, in his opinion, 

 the only way to destroy the cotton stainer is to destroy the 

 wild plants on which they feed and the old cotton thoroughly, 

 and have a close season. A great deal had been done in 

 ^Montserrat in this direction, more perhaps than was gener- 

 ally realized Mr. Pcncheon said that Mr Howes hatl had 

 a good deal of experience in controlling the cotton stainer. 

 In regard to !Mr. Nowell's remarks, Mr. Pencheon asked 

 whether bolls could be infected by needle pricks as well ius 

 by the sucking of the stainer, in other words, whether it 

 was definitely proved that the stainer carried the disease, 

 or whether disease got into the boll after the puncture 

 was made. 



The President said he thought it was conclusively 

 proved that the puncture of the boll bj' plant .sucking bugs 

 results in boll rot, and the jjractical point was that the 

 planter had to destroy the thing which punctured. 



Mr. Howes (Montserrat) said that about three years 

 ago they had experienced on his estates invasion^ 



