411 



THE AGRICULTURAL NEW; 



December 28, 1918. 



PLANT DISEASES, 



DISEASES OF COCO-NUT 

 GRENADA. 



PALMS IN 



MYCOLO(!}f'T s I:KI'01;T. 



(fioiicliiilad^ 



The little-leat disease, so far as could be learned, is up to 

 ihe present only of occasional and scattered occurrence- I saw 

 example-' among joung trees in plantations at the north 

 «nd of the island and on the west' coast. Its first manifesta- 

 tion is tlie appearance, in succession to normally developed 

 leaves, of diminutive leaves which are commonly more or less 

 bent or twi.sted. There is some brown spotting of the leaflets 

 in evidence before they unfold, acd the base of tlie petiole is 

 affected with a firm brown rot which does not usually pene- 

 trate very deeply. The treatment applied has been the lay- 

 ing bare of the seat of the injury by cutting away the strainer 

 and some of the adjacent outer leaves^ and the pouring of salt- 

 water, cassava water, .Teyes' fluid, or Bordeaux mixture 

 into the heart. The disease is likely to have a fatal 

 leniiinatioD, often apparently owing to infestation of the 

 damaged spots with palm weevil; but 1 saw several cases in 

 which norma! growth had been resumed, and recovery appear 

 ed complete. 



The disease appears to be due to an infection with a fun- 

 goid or bacterial organism, the identity of which I have not 

 yet had time to determine. There appears to be no relation 

 to bud rot. nor is there any evidence ol relation to the dwind- 

 ling of the leaves sometimes seen in old trees. S. F. Ashby 

 attribute.? a similar disease in -Jamaica to the action of a 

 .species of yeast. 



I recommend in ca.ses of this disease that the strainer be 

 c-irefully cntaway, and the leaves opened out as far as can be 

 done without injury. The cutting of the tissues, or any 

 violent injury i.-i to be deprecated, on account of the danger 

 ot attracting palm weevil. The affected region should then 

 be well covered with Jlordeiiu.v or Burgundy mixture which 

 adheres very much better if millc 'which tnay be soparattd or 

 fikimmed) \a u.sed in its preparation, in the proportion of 

 \ pint in each gallon 



A thick mixture, which may be expected to be particu- 

 larly suited to this purpose, and which is easi'y made up in 

 small quantities, may be prepared according to the following 

 foimula ; — 



Copper eulphatc — 4 cz. dissolved separately in 3 pints 

 of water. 



Washing soda —5 oz. in I pint of water. 

 Mil when dissolved, and add 1 i>iiitofmilk if it can be 

 obtained. The mixture may be. poured or swabbed into the 

 heart, but i.t far more effectively and ecinoniically applied 

 by any kind of rprayer. pusiiing the nozzle well down between 

 ihe leaves The idea of this trcatuieut is to give the tender 

 part- a eoa'ing whicJi is protective against infeclioo, and it 

 should be rvjieated when it is judged to be nei-es.^:iry from 

 rbi;- point of viuiv Wherf the lissnej are cut fr split, a 

 local applitatiou of carcolineuui might be tried, to keep out 

 palm weevil. 



The ' home remedies' referre'l to above are all open to 

 the objjction that their ingredients are readily soluble, and 

 must be quickly washed away by rain. 



The third type of affection noted, the condition of 

 debility due to want of drainage, root interference from 

 other trees, or exhausted or untilled soil will be dismissed 

 briefly, as being well within the planter's pow^r to deal with 

 by purely agricultural methods. It is only necessary to out- 

 line the distinctive features of the condition. The mature 

 leaves take on a general yellow or even reddish-brown 

 colouration ; usually the whole top has a sickly appearance ; 

 fruit production dwindles, or in old cases almost ceases ; 

 leaves and often fruit become infested with the round papery 

 scale insect (, /.>/'/(//'V«.> Jestnictor\ The trees do not die, 

 but make poor growth. New leaves remain green but a 

 short time- When the unfavourable condition is temporary, 

 as in the case of water-logging from floods or blocked drains, 

 the yellow" colour appears suddenlj, acd is soon removed 

 ^^ hen the roots are again set free to breathe. The remedies 

 are drainage, cultivation, and in some cases manuring- 



The first essential in dealing with the subject of bud rot 

 is to insist on discrimination between rotting of the bud in. 

 general, and the infectious disease known as bud rot in par- 

 ticular. Tlie e.xistence of a .-tinking rot of the heart is not 

 evidence of the specific bud rot disease Bacterial putrefac- 

 tion cf the enclosed tissues of the heart appears to be 

 as natural in a dead or dying coconut tree as it is 

 in the case of the internal organ of a dead animal. It is 

 seen in trees which die of root disease, and still less equivo- 

 cally, has occurred in an experiment made by the writer, 

 within two weeks of the insertion into the base of a vigorous 

 tree of an ounce of sodium arsenate In spite of much 

 investigation the only character by which the infectious bad 

 rot can be certainly recognized is by its infectiousness. It 

 may first att^ick the heart of the tree, or it may start at any 

 point among the outer leaves or tlower and fruit bundles, 

 reaching the heart only after many months. In both forms 

 the stem and roots remain healthy to tlie last. 



The on!}- cases seen during this visit which I regarded 

 as suspicious were tho.-e of some half-dozen mature bearing 

 trees on one estate, in which groups of outer leave?, not the 

 oldest, were discoloured and drooping These trees I have 

 asked the Superintendent '^f Agriculture to keep under obser- 

 vation- If the affection shows signs of progressinv?, it will be 

 advisable that they should be tired and sprayed, and if that 

 does not suffice, cut down and burnt. 



Wm. XouklT/. 



COTTON. 



SEA ISLAND COTTON MARKET. 



The Koport of Messrs. Henry W. Frost & Co,, on 

 Sea Island cotton in the Southern States, for the 

 week ended November 9, 1918, is as follows: — 



isr,.\.Nfir- We have had a continuance of a very dull 

 market, with only limited inquiry, but no demand: conse- 

 <|uently no sale.- are repcrted- 



Tbe un-«"4d -tock is gradually accumulating, which 

 rentiers the factors nn.re desirous of selling- I'uring this 

 period cf unsettled business, they continue o hold nominally 

 lor pricei. la.-t paid, but, .-hould any actual demand spring up, 

 they will prfibably be willing tf make n decided concession 

 in price to sell. 



