Vol. XIII. No. 315. 



TBE AGRICULTURAL NEWS. 



171 



ground stem portion8 of the cane stool, cutting oft' the water- 

 supply from the above-ground portions of the canea and 

 causing them to die with every appearance of having been 

 killed Ijy drought. 



This is the same appearance as that caused by the root 

 fungus (Maras}aius sacchari) and is due to the same cause, 

 namely the cutting oft' of the water-supply. It is shown by 

 the investigations reported that the root borer and the root 

 fungus are often found together attacking the same stool of 

 canes, and that in many cases the root fungus is secondary in 

 its attack and in its effect. 



The practice of digging cane stumps immediately after 

 the reaping of the canes is again recommended, but it is 

 definitely stated to have practically no value if the stumps 

 are left till they begin to dry out, because the grubs leave 

 them and penetrate into the soil where they may lie dormant 

 for some time. The length of this dormant period has been 

 the object of study and it has been found that grubs have 

 lived in captivity without feeding for periods ranging up to 

 334 days. This ability on the part of Diaprepes grubs has 

 a very important bearing on the problem of control and on 

 the attack of young plant canes when these follow canes in 

 the same fields without an intermediate crop. Xo insect 

 parasite of the root borer has been found though hundreds of 

 egg clusters and thousands of grubs have been e.^aniined. 

 Two grubs have been found in the field attacked by the 

 green muscardine fungus {Metarrhr.iu/ii aniscipliae) and trials 

 are being made with this fungus along the lines followed in 

 Trinidad in connexion with the control of the sugar cane 

 froghopper. 



The cane leif weevil (3J//(jr/irijus uriit'ihn:, Bailey) i.s 

 described and mentioned as a potential rather than an actual 

 pest It is a small, dark-brown weevil without perceptible 

 snout, which feeds on leaves of cane and corn, hiding during 

 the day in the leaf sheaths. The larvae and pupae are to be 

 found in the soil among the roots of these plants. 



The bronze hard back {Pliytalus siti it Id) ha.s frequently 

 been referred to in the Agricultural News and an account of 

 this insect appears in Pamphlet No. 73 issued by the 

 Imperial Department of Agriculture. P/n/taluf. Sniithi is 

 better known in Barbados as the brown hard back and it has 

 been called the Mauritius hard back .since it is in that island 

 that it has occurred as a serious pest, probably having been 

 introduced from Barbados with shipments of sugar-cane stools 

 in soil. 



In Barbados, this insect is held in check by its parasite 

 Tiplda parallela, which is a small blatk wasp. The investiga- 

 tions of Mr. Nowell have led to a very complete knowledge 

 of the life-history and habits of both brown bard back and its 

 parasite. The portion of the report in which this informa- 

 tion is presented is of much interest, and a few of the facts 

 will be briefly reviewed in the next issue of the Agricultural 

 News. 



RUBBER GROWING. 



BALATA IN BRITISH GUIANA. 



The notes from ISiitish Guiana which appear in the 

 India Rubber Journal for April 18, 1914, refer tT the 

 interesting conclusions arrived at by the officers of the 

 Department of Agriculture respecting methods of bleeding 

 balata. Collectors have been frequently warned against 

 felling trees for the purpose of obtaining, as they thought, 

 a greater quantity of latex; and it has now been proved that 

 by felling the tree, the results are actually less than those 

 obtained from the tree in a standing position. It is not 

 altogether generally admitted that the ordinary cutlass which 

 Mr. Bancroft has suggested should be used in the tapping 

 process is a success; true the knife made locally may not 

 actually be so efficient as a tool, but it must be remembered 

 that the balata tapper has to be taught his work, and it 

 requires a great deal of experience before an ordinary cutlass 

 can be used with sufficient skill to avoid penetrating to the 

 wood of the tree and causing damage. 



The same notes call attention to the false impressions 

 which have been made concerning the balata industry in 

 Dutch Guiana. There is more virgin forest in Dutch Guiana 

 than in British Guiana, and certainly the possibilities as 

 regards the production of balata are greater. The point is, 

 the industry has not been .so fully developed in the foreign 

 colony as it has been in our own. 



Coagulation and Strength.— Mr. Newton W. 



Barrett, B.A., contributes an article to the India Rubber 

 Journal of April 11, 1914, dealing with the subject of the 

 coagulation of the latex of llevea brasiliensis and its bearing 

 on the strength of rubber. It is shown that the physical 

 properties of the coagulation of Hevea latex depend on the 

 concentration of acid and salts in the serum at the time of 

 coagulation, and it is suggested that these have an important 

 bearing on the diti'erence in quality between rubber produced 

 by different methods, notably fine hard Para and Plantation 

 rubber. Suggestions are made for improving the plantation 

 methods of coagulation and the difficulties of standardiz ition 

 are shown. 



According to The Board of Trade Journal (April 30, 

 19 K) a Belgium decree has been issued prohibiting the 

 exportation across any of the frontiers of the Belgian Congo 

 of adulterated and impure rubbers. The Governor General 

 is to issue an Ordinance determining what rubbers are to be 

 regarded as adulterated and impure. All rubbers presented 

 for exportation must be accompanied by a certificate attesting 

 its examination delivered in accordance with the conditions 

 established by the Ordinance of the Governor-General. 



The brain in some birds is large iu proportion to the 

 body. If we admit that intelligence depends upon the 

 weight of the brain, then the goldfinch and canary must be 

 placed at the top of the list: the brain in these cases weigh- 

 ing one-fourteenth of the whole body. It is of interest to 

 note comparatively that the brain of the sparrow is l-25th, 

 the parrot l-42nd, the blackbird l-68th, the duck I-257th, 

 and the domestic hen l-412th. It would appear that domes- 

 ticity lessens the brain's usefulness. In man, the brain varies 

 between l-22nd and l-33rd of the body weight. 



The question of the yield per acre of tea is discussed in 

 some correspondence in the Planters C'hronicle,Ma,Tch 21,1914. 

 One planter establisheda field of 3 acresat an elevation of 2,000 

 feet high, which gave 216 lb. per acre during a period of four 

 years and six months, counting from the time ot sowing. In 

 another case a yield of 400 B). of made tea per acre was 

 obtained when the clearing was three years and six months 

 from planting. The average yield of tea per acre may be 

 taken as about 140 Ho. per annum. 



