Vol. XVIII. No. 459. 



THE AGRICULTURAL NEWS. 



373 



This is the first time this cane has been under cultivation in 

 St. Kitts, and it appears to be well suited to the lo^al con- 

 ditions. 



Tbe second place is taken by B.6:308 which has given 

 a mean tonnage of .3 2 3 tons can'^ per acre, and sucrose of 

 7,030 lb. per acre. This cane came first on the list for the 

 season of 191617, and is also first in the table of means for 

 all seasons. 



B.H.10(12) takes the third place on the list, with a 

 mean tonnage of 278 tons cane per acre, sucrose 6,9S0 Bj. per 

 acre, and a saccharine conteiA of 2-2.5 tti. per gallon. This 

 cane is remarkable for iis high saccharine content. 



With regard to the experiments on ratooas in ^t. Kitts, 

 it is noted that in 191617 the first place is occupied by 

 A. 2, which has given an average return of 27-4 tons c*ne 

 and 5,8o0 lb. sucrose per acre. This variety has again done 

 much better as a ratoon than as a plant cane. 



In 1917-18, howe\er, the first place in the ratoons is 

 taken by B. 1528, with a tonnage of 21-8 tons cane per acre 

 and sucrose content of 4,120 1b. per acre, while A. 2 drops 

 to the fifth place. 



In Nevis no experiments were conducted with ratoons. 

 In the season 1916-17, the results of those with plant cane.s 

 show that the first place is taken, as in St. Kitts and in 

 Antigua, by B. 6308, with the large return of 51 tons of 

 cane and 10,480 B). of sucrose per acre, and a saccharine con- 

 tent of 192 ft), pergallun. 



In 191718, the leading place is taken in point of 

 tonnaae by 6.4592, with 'he low return of 20'1 tons per 

 acre and sucrose content of 199. 



The report is of great interest, as it clearly shc'.v." the 

 necessity of investigation as to the suitability ot any 

 particular variety of cane to local environment. 



INJECTION OF ANTISEPTICS INTO 

 DISEASED TREES. 



In a paper constituting Part III of an account of silver- 

 leaf disease in Great Britain (The /onriial of Agricultural 

 Science, Vol. IX, Part 3), F. F. Brooks and M. A. Bailey 

 describe experiments to treat the diseased trees by the 

 injection of antiseptics, which may find application 

 iu the case of some stem and root di.seaaes in the 

 West Indies. Sulphate of iron v.a.s applied both as a 

 dressing to the roots and bj' plugging io into the sttms. 

 The treatment was not found to be sucoesiful. In view of 

 Ehrlich's woik on therapy, the effect of an injection of neo- 

 salvarson (606) was tried upon two silvered plum trees. 

 Holes were bored into these trees towards the base of the 

 stem, and 06 gram of this substance dissolved in .5c. c. of 

 distilled water was ponred int « each, the holes being after- 

 ward ^ealcd with plasticine. Two injections were made in 

 one tree and one in the other. The tne injected once did 

 not recoier, but in the one which was given two do.^es, the 

 upptr leaves wilted soon alter the unfolding of the buds, and 

 the top of the tree died ; this was probably due to the neo- 

 salvarson being too concentrated. The lower branches of 

 the tree recovered, on the other hand, and other healthy 

 shoots subsequently arose. It is likely that the fungus in 

 this tree was killed by th^ injection of neosalvarson, but 

 a considerable part, though iiJt all of the tree, was also killed 

 in the process 



'Preliminary experiments on the injection of dilute solu- 

 tions of certain aniline dyes into the branches of a large 

 plum tree having shown a possibility of s iccess by treatment 

 with these substances, fnrther trials of a more c^ref nl nature 

 were made. For this purpose, the main roots of the trees to 

 be experimented with were exposed at about the time of the 



opening of the buds; one, two or three of the roots were then 

 severed, and at once connected by means oi tubing with reser- 

 voira containing a dilute solution of the dye, placed at a high- 

 er level. The e.^posed portions of roots were enclosed with . 

 slates which were readily removable if the roots required 

 attention. At first, absorption of the solutions was rapid, and 

 when it slowed down the several ends of the roots were pared, 

 thus allowing absorption again to become vigorous. 

 Dilute solutions of the following dyes were used for this pur- 

 pose: Congo Red, Gentian Violet, Eosio, Methyl Violet, and, 

 Methylene Blue. It was not expected that the last-named 

 would prove toxic to the fungus, a- =•■ is often used in dilute 

 solution for intra-vit'un staining, but, being a very clear 

 stain, one thought it had the best chance of showing, by 

 staining the wood, whether sach dyes were carried to the 

 extremities of tb*> trees. The exact strength of these dyes 

 in the transpiration current cannot be given for ob- 

 vious reason.?, but it was considerably less than 1 in 2,000, 

 as the solutions were mide up at a strength of 1 in 2,000 or 

 1 iu 10,000. The results were as follows :— 



'(1) Eosifi. Of four treated trees, two recovered, although 

 ■some of the young leav.s withered in one of these. A third 

 tree shewed pirtial recovery, but .some of the leaves were 

 killed. The remaining tree showed no improvement. 



'(2) Methyl Viiilct. One tree recovered but two others 

 showed no improvement. None of the leaves were killed. 



'(3) Congo Red. The only tree treated with this 

 became healthy. None of the leaves were killed. 

 '(4) Gentian Viokt. As for Congo Red. 

 '(5) Methylene Blue. One tree recovered and one 

 remain- d silvered. Xone of the leaves were adversely 

 aflfected by this dye. 



'(G) Control. One tree in which distilled water was 

 absorbed in the same way did not recover. 



'In the trees which absorbed these dyes, the xylem of 

 the leaf petioles, especially the lower ones, became stained 

 after a tune, methylene blue being most evident, although it 

 could not be detected in the uppermost leaves of the tree. 

 The recoveries in these experiments were more nemerous 

 than have ever been observed by us to occur naturally, and 

 it is likely that some at any rate were due to these dyes 

 acting toxically on the fungus without seriously affecting 

 the host. At present, these results are only of 

 scientific interest, and until treatment of this kind has 

 been applied on a larger scale, much importance cannot 

 be assigned to it. From the practical point of view 

 nothing cm be done at present along the.se lines, as tbe 

 methods here used are too troublesc>nie and too costly. If, 

 however, certain of these dyes could be obtained at a cheap 

 rate, modified methods of injecting trees invaded by fungi 

 in tbe wood, migh' be tried with some prospect of success. 

 'While the above experiments were being carried oat 

 with dyes, other totic substances also were injeced in the 

 roots of silvered trees in the same way, but with little or no 

 success. Of two trees injected witli a weak solution of 

 ferrous sulphate (made up 1 in 1,000) one doubtfully recovered 

 and the other remained silvered. Solutions of corrosive 

 sublimate and quinine sul[)hate fmade up I in 1,000) were 

 without effect. Sodium arsenate, on the ether hand, made 

 up at the .same strength, had a rapidly toxic effect upon 

 the injected tree, and although the strength of the s ilution was 

 i|uickly reduced to 1 in 20,000, all the leaves *wi hered 

 except on one branch low down on the side away fmm 

 the place of injection. These leaves remained silvered, but by 

 the following year all the upper part of the tree wrs dead, 

 and only a few sucker shoots, which were healthy, 

 remained.' 



