li 



THE AGRICULTURAL NEWS. 



Jan LAKY 1, 1916 



PLANT DISEASES, 



A STEM DISEASE OF SUGARCANE IN 



BARBADOS. 



At a recent meeting of the Barbados Agricultural 

 Society, according to a report in the Barbados Advocate 

 of December 22 last, Mr. J. K. Bovell, Superinlendent of 

 Agriculture, made a statement as to the existence in Barbados 

 at the present time, of a disease of .sugar-cane .similar to or 

 identical with that occurring in India, described by E. .J. Butler 

 and Abdul Hafiz Khan {Memoirs of the Department of 

 Agriculture in India, Botanical Series, Vol. VI, pp. 181-90) 

 Under the name of wilt, and shown to be due to a fungus to 

 ■which the name Cephalosporium sacchari was given by the 

 :iirst-named author. 



A review of the paper containing this descvijition was 

 given in the Agricultural Neicf, Vol. XIII, p.62, and it was 

 tliere mentioned that a Cci)halosporium has been met with in 

 the West Indies on pieces cut with the usual precautions from 

 the interior of diseased canes. Tliis referred to observations 

 by the present writer on Barbados material, so that the 

 occurrence now recorded canncjt be regarded as new-. 

 Evidence of the pathogenic nature of the fungus is 

 ecjually lacking from both We.st Indian records, but the 

 general resemblance of the disease to that described by 

 Butlei and Khan, and the absence of other fungi from 

 a con.siderable number of diseased canes examined, afford some 

 grounds for the presumption that the Cejilialosporium is its 

 cause. 



In view of the possibility of the occurrence of tlu; 

 affection in those islands in which the Imperial Department 

 of Agriculture is directly interested, tlie writer took 

 advantage of an opportunity of examining early in November, 

 an estate on which the disease was reported to have 

 api)eared to a considerable extent. It was found that the 

 arte(-tion was generally distributed, but not abundant, 

 throughout several fields of the variety B. 64.50. Adjacent 

 fields of White Trans])arent and B. .376 were examined and 

 appeared to be c^uite healthy; but according to Mr. Bovell's 

 announcement, the disease has been found to occur, to an 

 extent not stated, on these varieties also. 



The opinion formed by the writer was that the disease at 

 that time was entirely, or almost entirely, confined to canes 

 whose water-supply had been interfered with, most often as 

 a result of wrenching by high winds, and in other ca.ses by the 

 development of Marasmius sacchari in the cane base. A second 

 visit some weeks later did not reveal much apparent extension 

 of the aflec-iion, but the amount of the damage cannot be 

 properly estimated until the canes are reaped. 



The external symptoms of the di.sease are similar to 

 tho.se of the red rot once familifir in the West Indies on the 

 Bourbon cane. The internodes affected are usually near the 

 l)a.se; the surface first .shosvs a reddi.sh-brown patch, and 

 •eventually a sunken spot is formed which later becomes 

 infested with secondary fungi, no'.ably Melanconium sacchari. 

 On splitting the cane some form of reddish di.scoloralion is 



seen; this may be somewhat superficial, or may extend 

 through the centre of the cane. The fully developed colour 

 is a muddy blackish-red. 



No notable wilting of canes as de.scribed by Butler and 

 Khan has so far been observed. 



The threatening appearance of the Barbados outbreak 

 led to a request for observations in'St. Kilts and Antigua 

 being addres.sed from this Office to the agricultural officers 

 cojicerned. Since writing the above paragraphs an examin- 

 ation has been made of material received from Mr. F. B. 

 Shepherd in St. Kitts. The specimens are of White Trans- 

 parent cane, and are accompanied by the information ihat 

 they are from a district in which that variety has previously 

 jaroved very susceptible to fungoid diseases, and for that 

 reason is seldom planted. The field from which they were 

 obtained was about nine months old, and the canes were 

 drying up in a manner typical of a fungus attack. Canes 

 of other varieties were remarkably healthy. 



The appearance of the canes when split coincides exactly 

 with tiiit represented in Butler and Khan's coloured plate, 

 namely, reddish longitudinal streaks following the course of 

 the vascular bundles. The correspondence is much closer 

 than in the case of the Barbados examples ou B. 64J0, 

 examined by tlie writer. 



Ten pieces were cut with suitable precautions from the 

 interior of several of the canes received, and were placed in 

 sterile tubes, and of the.se eight have developed a Cephalos- 

 porium form corresponding in appearance, and in the size and 

 range of length of the coni<lia, vnth Butler and Khan's 

 drawings and descri]:ition. One of the remainder developed 

 a culture of Thielaviopsis, which is pre.sent on the cut ends of 

 most of the canes received; the fungus in the other has not 

 as yet developed sufficiently foi- identification. 



It seems probable that this fungus is widely distributed 

 in the West Indies. Po.ssibly it was an unrecognized factor 

 in the complex known as rind di-sease which le<l to the 

 abandonment of the Bourbon cane. Its apparent ability to 

 produce a somewhat serious disease, in varieties resistant to 

 the main factor in rind disease, the red rot due to Colletotri- 

 chum falcatuni, gives it both practical and theoretical 

 interest. 



W. N. 



Those who are interested in the question of fruit or 

 vegetable grading may care to refer to the Monthly Bulletin 

 of Agricultural Intelligence and Plant Diseases for January 

 191-"), which contains an illustrated account of the Newton 

 fruit-grading machine. It consists of a conveyor band passing 

 over a pulley at each end which carries the fruit along 

 a padded surface. On a spindle is a large pulley round 

 which passes a leather belt that drives the grading rollers at 

 varying height above the conveyor band. The grading rollers 

 are covered with felt and have spirals on them for correctly 

 grading the fruit. The first grading roller, being the highest 

 above the band, deflects the largest fruit on to the first tible, 

 and pernuts the smaller fruit to pass underneath to be 

 similarly de.Ut with by the succeeding rollers. The machine 

 with the table folded, measures 2 feet by G^ feet, and weighs 

 140ft). Its price is £{'), and its rated capacity is 1.5 cwt. of 

 fruit per hour. 



