Vol. IX. No. 205. 



THE AGRICULTURAL NEWS. 



SUGAR INDUSTRY, 



EPIDEMIC SUGAR-CANE DISEASES 



OF THE PAST. 



H. ('. Prinsen (ieerligs gives an account, in the Intti- 

 iiiitioHiit Sw/ar Jouriiiil for January of this year, of notablc- 

 L-pitlemics of diseases afteeting the sugar-cane that have shown 

 themselves in past year-. He first draws attention to the 

 passing, through di.sease, of the Bourbon cane in the West 

 Indies -a matter which, it may be mentioned, has recent 

 attention in an article liy H. A. Tempany in the West IiidUiii 

 lliiUttiii, Vol. X, No. 1 — and then suggests that, in addition 

 to the adoption of the remedial measures recommended for 

 checking those diseases, the fact that diseases possess cycles of 

 activity may eventually lead to the resumption of the culti- 

 vation of this cane on a large scale. The account then goes 

 on to treat of past epidemics of various pests, and forms the 

 basis of the following information in conne.xion with them. 



llecords show that, as early a.s the year 1-502, caterpillars 

 of one or more kinds became such a serious pest of the sugar- 

 cane in .Madeira as to make it necessary to import sutrar into 

 that island, whereas it had forineily posses.sed a considerable 

 e.\|)orl trade. A few years later, sugar was exported again, 

 -SO that the insect or insects responsible for the damage must 

 have soon ceased to e.xist in abnormal numbers. 



The sugar-cane in Mauritius and Jteunion wa.s attacked 

 to a serious extent In the year 184 1 by a fungoid disease, and 

 the matter became so important, in regard to the welfare of 

 the island.s, that canes were imported from ("eylon, with the 

 hope that a variety resistant to the di.sease would be obtained. 

 On their arrival, the canes were found to be infested with 

 moth borer, and were ordered to be burnt; a it\i must have 

 escaped destruction, however, as after that date, this insect 

 pest was found in Mauritius. No further eftbrt Vas made 

 to introduce disease resistant canes, and, notwithstanding 

 this, the disease became much less severe, and two years 

 afterwards the crops became healthy once more. It is sug- 

 gested that, probabl)-, some of the varieties cultivated in 

 Mauritius were immune to the disease, while the others were 

 very liable to its attack.s, so that the power of the former to 

 .survive led it to take the place of the susceptible varieties. 



In Java, during the year 18.S2, the cane variety which 

 had, so far, sutticed in every way was attacked by a mysterious 

 disease which threatened to exterminate it. The origin of 

 this disease was never traced, but it was proved to be trans- 

 missible by tneans of cuttings. The disease sjiread through- 

 out the island in a direction from west to east^ but decreased 

 in virulence as the area afTected by it became larger,so that the 

 attack was most serious in the first year. All ordinary direct 

 remedies for combating it failed, and it was finally controlled 

 by the careful use of sound cane tops for planting, by the 

 introduction of new varieties of cane, and by the raising of 

 fresh ones. Later, in 1900, some estates in Java were 

 attacked by a fungoid disease, which was very promptly 

 .stamped out by adopting the policy of selecting for planting 

 cane varieties that were resistant to it. 



The rise of sudden epidemics may be ex[ilained, in some 

 cases, by the fact that sajirophytic fungi exist which become 

 parasitic, for reasons that are not plain to be discovered, 

 and then appear as very serious pe.sts in relation" to .some 

 variety or varieties of cane. The explanation of the sudden 

 increase in the degree of parasitism shown in such cases may 

 ■be either that the virulence of the fungus increases, or that 



the power of resistance of the affected varieties has 

 decreased. In any case, it has often been noticed that 

 a good cane variety has suddenly been seriously affected, 

 while others remained quite untouched, and then that, after 

 some time, the di.sease had died out. This last circumstance 

 is interesting, but it is evident that planters cannot afford to 

 wait for such an event; they must take measures which will 

 be quickly effective in supplying them with good crop.s, and 

 may do so by replacing the oid varieties by new ones. 



These considerations show that it is dangerous for any 

 sugar-growing area to possess only one variety of cane. Not 

 only, when that variety is seriously attacked, is time required 

 for its replacement, but the planters are subjected to the dan- 

 ger of the hurried importation of canes which may bring new 

 pests with them to a place where the natural parasites of these 

 do not exist. This forms an argument on behalf of the policy 

 of having varieties in reserve, which will be on hand for the 

 purpose of replacing those that have become disea.sed, at the 

 earliest possible opportunity. 



ONIONS IN ANTIGUA. 



The following report on the condition of the onion 

 industry in Antigua has been received from Mr. T. Jack- 

 son, Curator of the Botanic Station in that island:^ 



During the last few years, the area of land planted in 

 onions in Antigua has varied very slightly. For the present 

 year (1909-10) it is about 58 acres. This area is larger by 

 8 acres and 6 acres than those of last year and the year before, 

 respectivel}-. During the present sea.son, the crop has been 

 particularly free from insect pests, and at the time of writing 

 looks promising. The following table gives some figures that 

 may be of interest: — 



Year. Seed imported. Area, No.' of crates Value. 



lb. acres. exported. £, s. d. 



1907-8 18U 52 .3,505 850 11 



1908-9 1.38 ,50 689 220 



1909-10 181 58 



The great difference between the exportations for 1907-8 

 and 1908-9, without a corresponding decrease in the area 

 cultivated, must not be taken as indicating a reduced return 

 per acre, for the crop during 1908-9 was normal: the probable 

 explanation is that the greater part of the latter crop was 

 sold locally, while most of the onions produced in 1907-8 

 were exported. 



The annual acreage under onions could be increased 

 considerably in .Antigua. They are grown as a catch crop 

 with sugar-cane, and, under these conditions, when the land 

 is cultivated early, they interfere very little with the routine 

 work connected with the main crop. 



On one estate in 1908, two plants matured seeds, the 

 parents originating from seed planted that season. This is 

 the second time that this somewhat peculiar incident has 

 occurred in Antigua. (See Reports <,n the Botanic Station, 

 Experiment Plotn and Ai/ricitltural Education, Antigua,. 

 190G-7, p. 39.) On the first occasion the seeds germinated, 

 but the plants did not mature. At the present time, liowever, 

 a fair number of healthy young plants, raised from this seed, 

 are growing in the island. 



In a later communication, Mr. .Jackson states that 

 six plants from the above-mentioned locally raised seed 

 are forming fruit during this season, and suggests the 

 possibility of the further transmission of the peculiarity 

 of producing seed in one season to the progeny of these 

 plants, so that annual varieties of the onion may be 

 obtained ultimately. 



