CO885-(19-20) — Page 375

PUBLIC RECORD OFFICE

19

C.O.

Reference :-

885

20 PUBLIC RECORD OFFICE, LONDON

ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO

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purpose the Committee estimate that there would be required, the first year, about £75, made up as follows:-

28 specimen boxes at 7s 11d. each ... Cost of freight, &c.

Metal cabinet for 28 Schmitt boxes Packing

Freight

Miscellaneous, such as labels, naphthalene flakes, naphthalene cones, spreading cloth, insect paste, mailing and shipping boxes, glass tubes with corks, specimen jars, &c. Salary of clerk

£ 9. d.

11 1 8

1 0 0

2 18 4

0 3 14

1 0 0

8 18 10 50 0 0

75 0 0

(d) That should the permanent committee be appointed and the necessary funds provided for carrying out the work, the parochial medical officers be asked to co-operate with the local committee by making collections in their districts, with special reference to insect-borne diseases; and that the Superintendent of Agriculture, who has been working on the subject of the pests attacking economic crops of the Island for some years and who has already made a collection of a number of these insects, be asked to assist in any way he can in the matter.

With the idea of emphasising the reasons already given for co-operating in the work that is being carried on by the African Entomological Research Committee and the importance of knowing something about the life history of insects attacking animals and plants, if may be mentioned that, as is well known, yellow fever in endemic areas like Havana and Rio de Janeiro has been practically stamped out and epidemics of the disease in New Orleans, Barbados, and other places have been subdued by measures directed solely to the destruction of, and protection from, infected mosquitoes, Stegomyia fasciata, F. (= calopus, Mg.) being known to be a carrier of the disease. Attention may also be called to the fact of the reduction of the death-rate from malarial fever in those countries where mosquitoes of the genus Anopheles are prevented from breeding. As is also well known, Filariasis, locally known as " fever and ague," which is so prevalent in Barbados, is probably caused by a tiny worm, Filaria nocturna, which, according to Dr. Lowe, is conveyed by the mosquito, Culex fatigans.

The loss occurring in Trinidad from malarial fever among the agricultural labourers, especially the Indian immigrants, which is now known to be preventable, may be judged from a paper read by Professor Carmody, Director of Agriculture, &c., in that Island, at the Brussels International Congress. In that paper he

says:-

Taking the sugar estates, on which the number of immigrants approaches 10,000 a number large enough to give trustworthy statistical results --we find in the best year (1905) more than half the total supply was entered in the case books as attacked by malaria, and with one excep- tional year (1909), the number of cases treated has exceeded the total number of immigrants.

The money value of the loss can be easily calculated. Taking 1909, the last year for which figures are available, there have been 7,744 cases on sugar estates, each working unit being worth at least 30 cents per day. This represents an annual loss in the earnings of the labourers of $2,323.20 if the malaria attack only lasts one day, and $9,292.80 if the attack last four days. Four days may be taken as a low average rate of duration of malarial fever of the ordinary type. To this must be added the indefinite loss of efficiency during the period of convales- cence, which may extend to ten or twelve days.

In a Colony dependent upon immigration for its labour supply, another aspect presents itself. The loss of 7,744 working units per year represents

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for 300 working days a loss of about 26 immigrants per year if disabled for only one day, or about 100 immigrants if the disability extends to four days. This loss is a serious one in a colony such as Trinidad.

In the case of Trinidad these statistics are based on 10,000 of the agricultural labourers, but as all the inhabitants are more or less attacked by malarial fever and as the total number of inhabitants of Trinidad was on 31st March, 1907, estimated at 338,992, some idea may be gained of the loss to that Colony in labour alone through malarial fever.

In the case of economic entomology, it may be mentioned that some years ago,, somewhere between 1897 and 1900, an insect known as the leaf hopper, Perkinsiella saccharidida, Kirkaldy, was introduced into the Hawaiian Islands. That insect, owing to the absence of its parasite, spread very rapidly, and so great was the damage done to the sugar canes that it was thought at one time the sugar industry would be ruined, as the loss sustained by the attacks of this insect for 1903 alone was calculated to be three million dollars. Fortunately, however, there was an experi- ment station in that Island the officers of which, immediately the leaf hopper was found to be doing injury, made inquiries in various countries where it was thought probable that this pest existed, to ascertain whether anything was known about it, and, if so, whether it was parasitised. After some six months, specimens of the insect were forwarded from Queensland by Mr. James Clarke, of Cairns, who wrote to inform the officers of the experiment station in the Hawaiian Islands that the leaf hopper had been known in Queensland for many years, that it was their only species, and that it did no noticeable damage, and was, therefore, kept in check by some efficient natural enemy. On the receipt of this information, Messrs. Perkins and Koeble, two entomologists, were despatched to Queensland, where they made collections of insects parasitic on the leaf hopper. By 1906, on one estate which had suffered great loss from the attacks of the leaf hopper, it was found that 86 per cent. of their eggs had been destroyed by the parasites, and from then on this pest has been kept in check and is now practically of no economic importance. In fact, as was pointed out in the "Hawaiian Forester and Agriculturist" in 1909, the practical result of the introduction and acclimatisation of the imported parasites has been so great that all anxiety on account of the leaf hopper seems now dispelled

Owing to the success obtained with parasites on the leaf hopper in the Hawaiian Islands, the work in this direction has been extended to a considerable extent, and a number of other parasites attacking Lecanium and other scales have been intro- duced and are, judging from the reports received from those Islands, keeping a number of these pests in check.

To give an instance of where knowledge obtained in other countries has been of use in Barbados, it was mentioned by Mr. J. R. Bovell that in August last year he observed at Mistletoe, St. Laurence, Christ Church, a fungus attacking the black scale Lecanium nigrum on hibiscus plants, and knowing that for some years fungus parasites had been at work in Florida and subsequently in Montserrat and Dominica keeping scale insects in check, he obtained branches of hibiscus plants and tied them in trees at Dodds, where the black scale Lecanium nigrum and other scales of the same genus and Protopulvinaria pyriformis were doing a considerable amount of injury to the trees, and that in a short time this fungus spread to such an extent that at one time it was difficult to find scales that were not parasitised. Subsequently, branches of trees with parasitised scales were taken to Queen's Park, where the fungus rapidly spread among such scales as are attacked by it; branches with the attacked scales were also sent to other places where the scales were found doing injury. He also mentioned that during the dry weather the attack of the fungus seems to be stayed and the scales commenced to increase again, but on the advent of the rains he noticed the fungus spreading among the young scales.

In conclusion, it may be mentioned that Mr. J. R. Bovell has intimated his willingness, if His Excellency the Governor permits, to supervise the work of the man it would be necessary to employ for looking after and shipping the specimens, &c., provided the work is carried out and the collection kept at his department.

F. J. CLARKE,

July 6th, 1911.

Chairman.

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