Yol. V. No. 118. 



THE AGEECULTURAL NEWS. 



347 



FUNGUS DISEASES OP SUGAR-CANE IN 

 BENGAL. 



The above is the title of a bulletin by Mr. E. J. 

 Butler, M.B., F.L.S., forming the third number of the 

 first volume of the botanical series of the Memoirs of 

 the Department of Agriculture in India. It is intended 

 to serve as a preliminary account of the principal 

 fungus diseases that affect sugar-cane in Bengal, and 

 v\ill form a basis for further experimental research at 

 the Agricultural Research Institute at'Pusa. 



Several of the diseases described are familiar to experi- 

 mentalists with the .sugar-cane in countries other than Bengal. 

 Extracts from the work done on the fungus diseases of the 

 sugar-cane at the laboratories at Kew and at the research 

 stations in Java, Madras, and the West -Jndies are briefly 

 summarized and compared with results of observations from 

 1902 in Bengal. 



Several of the results obtained are of considerable 

 interest, for they suggest the need of additional researches to 

 establish fully some points of importance. Some points that 

 need to be worked out are suggested by the author. 



Of stem diseases, the ' red-rot ' is considered to be the 

 most serious disease with which sugar-cane growers in Bengal 

 have to contend. The external appearance of the disease 

 would at first suggest drought, but on splitting open a cane 

 the tissues are found to show a reddish discoloration in one 

 or a few of the lowest internodes, extending downwards into 

 the stool and later proceeding upwards towards the top of 

 the cane.* 



This disease is held to be caused by the fungus 

 Colletotrichuiii falcaticm, Went, but the connexion between 

 the presence of the fungus and a boring insect thnt is almost 

 invariably present has not yet been established with certainty. 



It would appear that yellow canes of the Bourbon type 

 are particularly susceptible to its attack, for in 1902 some 

 fields planted in a variety of this type for the first time with 

 seed from a diseased area were badly attacked, while other 

 varieties of canes were ^uite healthy. The following year 

 this localization was the more marked. 



Samples of diseased and healthy canes were taken for 

 analysis. The results were most interesting. Diseased canes 

 showed a diminution of 45 per cent, in the total available 

 sugar and a marked increase in glucose. Subsequent experi- 

 mental work suggests that the actual consumption of sugar 

 by the fungus is slight compared with its inverting action. 



The author is of opinion that this disease, which has 

 also been reported from Madras, and from Java as the ' red 

 smut,' is identical with the 'rind disease ' of the West Indies 

 except that it is very rarely followed by the Mt'lanconiura 

 stage of Trkhosphaeria Sacchari, Massee. 



In dealing with the means that the fungus has of 

 spreading, the conclu-sion is arrived at, provisionally, that the 

 ' sets ' themselves, in the majority of cases, carry the disease. 

 Therefore, the most important considerations in regard to this 

 disease are held to be (1) choice of resistant varieties and 

 (2) careful selection of seed canes for planting. 



Of the other stem diseases, ' smut,' caused by Ustilago 

 Sacchari, Kabenhorst, is confined to certain varieties, and 

 experiments to inquire into whether spore-infection of sound 

 sets can be prevented by means of steeping them in copper 

 sulphate are being continued. 



♦ Other examples of ' red rot ' show that the disease may- 

 appear in the nodes towards the middle of the cane, the roots, 

 and also the leaves. 



Melanconium form of Trichos2)Juieria Sacchari, Diplodia 

 cacaoicola, P. Henn, and Ci/tospora Sacchari, Butl., sp. nov., 

 have also been found attacking stems of sugar-cane, but are 

 probably of only minor importance. 



The ' pine-apple ' disease of cuttings caused by Thiela- 

 viopsis tthaceticus. Went, has been found on imported canes 

 from Java and Mauritius. This clearly shows the necessity 

 of careful examination of imported seed for signs of disease, 

 and suggests that laws governing disinfection and importation 

 should be passed by all countries. 



A ' black-rot,' caused by Sphaeronaema adiposiua, Butl., 

 is described for the first time, but it seems that this fungus, 

 like that causing the ' pine-apple ' disease, causes only the 

 failure of sets. 



Leaf diseases are not striking in their effects, but it is 

 thought that where they are prevalent they are responsible 

 for considerable losses in the yield of sugar. A new species 

 of Cercospora is described as the ' brown leaf-spot ' and may 

 be compared with the 'red-spot' which is common in the West 

 Indies, and the ' eye-spot ' of Java canes. Spreading of leaf 

 diseases can, as a general rule, be checked by careful burning 

 of all diseased leaves. 



The author gives certain recommendations for treatment 

 of the several diseases, but he is of opinion that the chief 

 means of combating these diseases lies in the choosing of 

 varieties less liable to attacks, or in the production of other 

 resistant varieties by careful selection or hybridization. 



RAINFALL IN ANTIGUA. 



Mr. H. A. Tempany, B.Sc, has forwarded the 

 following table showing the rainfall for the month of 

 September on seventeen different stations in Antigua, 

 which together represent fairly well the precipitation 

 over the entire island. Mr. Tempany says : — 



The mean rainfall for the month for all these stations is 

 18 48 inches. 



The month has been phenomenally wet for this island; 

 in fact, the rainfall is the greatest recorded in any one month 

 as far back as the detailed records of the rainfall kept in this 

 office extend, that is to say, for a period of eighteen years, 

 and it is probable that in reality it is a record for a consider- 

 ably longer period of time. 



Rainfall for the month 

 Station. of September 1906. 



Fitches Creek 

 Parham New Work 

 Claremont ... 

 Bellevue 

 Fare's 



North Sound 

 Blubber Valley 

 Botanic Station 

 Orange Valley 

 Weatherill's 

 Cedar Valley 

 Bendal's 

 Walling's ... 

 Dimsdale . . . 

 Cassada Garden 

 Thibou Jarvis 

 Montpelier . . . 



Mean of all stations- 



Inches. 



2256 



21-29 



20-95 



20-28 



20-00 



19-51 



19-37 



18-86 



18-38 



17-87 



17-30 



17-09 



16-93 



16-63 



16-52 



15-90 



14-7» 



-18-48 inches. 



