202 



THE AGRICULTURAL NEWS. 



June 20, 1914. 



INSECT AND FUNGUS NOTES. 



THE USE OF CARBON BISULPHIDE IN 



EMULSION AT MARTINIQUE AND 



GAUDELOUPE. 



Experiments have been made from time to time in the 

 British Wtst Indies on the use of carbon bisulphide as a soil 

 insecticide and soil disinfectant, on the lines of the methods 

 which have been claimed to be very successful in European 

 vineyards. It has been found that the application of carbon 

 bisulphide in its ordinary form gives very unsatisfactory 

 re.sults with our soils and crops. The need of a good and cheap 

 soil-sterilizing agent for dealing with the root diseasts of 

 permanent crops is strongly felt, and the need of a means of 

 destroying root grubs not less so. 



"We are much indebted to Mons. G. Bordaz for copies 

 of the Martinique newspaper, LaPai:e,{oi May 9 and 14, 

 1914, containing an article of which he is the author dealing 

 with the preparation and use of carbon bisulphide in emulsion. 



It may be noted that the root disease (pousridic' des 

 racines) of which Mons. Bordaz speaks is most probably 

 a Rosellinia disease, similar to, or identical with those occurr- 

 ing in St. Lucia and Dominica, while the name Diaprejyes 

 famelicus is synonymous with Exo2ihthalmus fii meiicus, an 

 insect diftering little from E.io2jhthalmus esuriens and the 

 varic'Us species of Diaprepes occurring throughout the West 

 Indies. 



The article, freely translated, and with British weights 

 and measures and Barbados prices substituted is as follows: — 



Cacao, coffee, lime and other trees are destroyed 

 in Martinique as in Guadeloupe by different animal or 

 vegetable parasites, the most common of which are the 

 vrhite giubs and the eel-worms among the animal parasites, 

 and the root disease amongst the vegetable. 



Among the white grubs the most dangerous is the larva 

 of a handsome beetle very common in our colony — Diaprepes 

 famelinis. This larva is found to some extent in all 

 soils, but particularly in those of an alluvial nature. It is 

 this larva which causes, in most cases, the death of the 

 young cacao trees, which comes unexpectedly and rapidly 

 in a spell of sunshine, and is ordinarily attributed to crickets 

 or to the story of the tap roots coming in contact with 

 stones heated by too ardent a sun, etc. 



We have been able to confirm the fact that it has 

 attacked the plantations of lime trees established a few years 

 ago. In short, one can say that it is found wherever the 

 newer crops have replaced sugar cane. It is doubtless for 

 this reason that it is commonly said that permanent crops, 

 and notably cacao trees, cannot succeed in land previously 

 planted for a long time in sugarcane. 



The eel-worms chiefly attack coffee, and especially 

 Arabian coffee, known here as Martinique coffee. In various 

 studies publi-shed in 1899, M Thierry, now Chief of the 

 Department of Agriculture ar:l a cacao planter at Case 

 Navire, has fairly proved that th3 eel- worm was the principal 

 cause of the disappearance of tiie well-known plantations at 

 A'auclin. He has proposed either grafting on Liberian 

 stocks or treatn\ent -.vith carbon bisulphide, but his has 

 merely been a voice Jiying in the wilderne.ss, and if we 

 still have a little coffee in Martinique we owe it to the 

 plantations of Liberian and of Robusta coffee which have by 

 degrees been established, whereas a simple treatment with 



carbon bisulphide would have helped to supply the necessary 

 vigour to the Arabian coffee trees, dying then, and now dead, 

 and to produce once more good crops and bring back prosper- 

 ity throughout the region now ruined and desolate. 



The root disease occurs most frequently in compact damp 

 soils, and also in light soils superimposed on an impermeable 

 subsoil. Its attacks are particularly serious during rainy 

 years. It is almost as terrible an enemy for permanent crops 

 as the Diaprepes. Now these three diseases, serious as they 

 are, are all easily curable by the treatment with carbon 

 bisulphide. The experiment was first made, as has been said 

 above, for the eel-worm and the root disease on coffee trees. 

 Later, after long and expensive investigations carried out on 

 the plantation of Case Navire, M. Thierry asserts that the 

 larva of Diaprepes is unable to withstand a similar treatment. 



Several proprietors in the colony followed his example 

 and their plantations have been kept out of danger. 



On the strength of such conclusive results one hoped 

 that the use of carbon bisulphide would become general and 

 that a simple occasional treatment would be a regular and 

 ordinary method of cultivation. Such a hope was vain. 



Under the impulse given by the Department of Agri- 

 culture, which freely distributed plants of the best species to 

 those planters who asked for them, many new plantations 

 were tried. This distribution of plants was practically a com- 

 plete loss, the new estates succumbing .steadily and 

 fatally under the attack of Diaprepes, the eel worm and the 

 root disease. The results of these numerous and expensive 

 free distributions of plants are to be summed up now as 

 follows: The Arabian coffee has practically disappeared 

 from cultivation in the colony, and in spite of the coming in 

 of important cacao cultivations, and in spite of the large 

 number of young plants delivered for abou.t ten years by 

 the Department of Agriculture, we see that the exportation 

 of cacao not only makes no progress but has rather a tendency 

 to diminish. The year 191.3 only shows an output of 

 528,000 kilos., whilst the average for the last five years 

 reached 555,000 kilos. 



Leaving other reasons on one side, one may saj- that 

 apparently the difficulties the proprietors found in procuring 

 the carbon bisulphide, and the difficulties that appeared in its 

 use afford reasons why this treatment, so etHcaeious in 

 every case, has not been more generally applied. 



This difficulty has now disappeared and there only 

 remains to be considered the method of employment. 



On large properties, without doubt, the use of emulsion 

 pumps is always to be recommended. At Case Navire, the 

 Fateur pump is employed. The results are marvellous. The 

 white grub and also the root disease disappear as if by 

 magic, and where one only saw trees wasting away, there is 

 established a uniform and luxuriant vegetation. But the 

 emulsion pump is not within the reach of everyone. If it 

 is cheap in the application of the treatment, it is expensive 

 to buy. difficult to transport on rough lands, and must be 

 handled delicately. 



On the other hand, the soil injector (pal) which gave 

 such convincing results in France in the war against 

 Phylloxera, is less to be recommended for cacao and coffee 

 trees because their root systems differ from that of the 

 vine. It gives unequal and frequently dangerous results, 

 and is almost always useless in compact soils or .soils of an 

 insufficiently friable nature. For small planters the pur- 

 chase price is again somewhat high. 



Under the circumstances, the most efficacious method 

 is to pour the emulsion round the foot of each tree. 

 After the results obtained by M. Thierry on the Case 



