Mosquitoes

The Pervading Pest of the Tropics

By N. C. Mackenzie-Hunt, Nabouwalu, Bua, Fiji r[E worst scourge of mankind in the tropics and sub-tropics is the mos quito.

It is reported, on good authority, that mosquitoes have got as far north as Great Britain.

The Pacific mosquitoes lay their eggs in stagnant water, swamps, still holes of river water, and hollows of trees.

The most common hatching grounds are coconut husks and empty meat and jam tins, which are carelessly thrown about plantations by the labour, etc.

The best way of ridding yourself of the breeding-grounds is simply to see that the labour burn or destroy by bury ing all coconut husks; and that all empty tins are buried. Several pits can be dug for this purpose, about 12 to 14 ft. deep, and covered in as each batch of empty tins is thrown in. A similar procedure can be followed with coconut husks, but, in lieu of a pit, trenches can be dug between the palms, and all husks buried therein. This will also act as manure, as the husks rot very quickly when in contact with soil.

The female mosquito bites, whilst the male lives entirely on fruit and flower juices. They also alight on sugar and jam and anything sweet, and seem to become semi-intoxicated with the sweet ness, it being rather difficult to dis lodge them in a hurry.

Anything which tends to become a breeding ground for the pests should at once be done away with, such as Ivi trees (Tahitian Chestnuts), gnarled trunks and branches.

Medical science says that they do not fly very far from the surface of the ground. This is entirely a mistaken idea. The writer has proved beyond doubt that they will invade houses, close to the sea, at an elevation of at least 40 to 60 ft. —the height, more or less, of an average coconut palm.

Ivi trees (pronounced Eevee), Tahitian Chestnut Incarpus Edulis which attain an average height as above men tioned, are their natural home. They can be found among the thick leaves of these trees, and they breed in the cavi ties in the branches, and the trunk.

The pests are particularly bad during westerly and northerly weather, and less annoying during southerly and south

east- trade winds. From personal ob servation, it would seem that where there are many Ivi trees, and a pre ponderance of other similar growth, they will be particularly bad.

In Fiji, their activities usually com mence round about 3 or 4 p.m., and con tinue unabated throughout the night, and until after 9 a.m. It is possible, however, to be bitten by stray mosquit oes at noon, and more especially when going through thick jungle. It is usu ally the large brown mosquito which.

bites in the day-time, although the Culex Anopheles, the little black and white fel low, and the others, do their share.

THERE are many diseases, some fatal, transmissible by mosquitoes. Those which transmit yellow and blackwater fever very often thrive in the vicinity of towns.

Although the malaria mosquito also has the same habitat, he usually pre fers the thick damp jungles and forests.

Although the malaria mosquito is pre

sent in Fiji, and quite common, there is strange to say, no malaria. This may be due to the absence of fever-breeding germs, or to climatic conditions. Much has been written on the possible trans port of malaria from infected places to uninfected areas, by aeroplane. This pos sibility is ever present, but there seems to be a definite line of demarcation be tween places infected, and those unin fected.

The only thing. to do is to use every conceivable means at our disposal for the prevention of the spread of this menace. Larvae of the malaria mos quito usually take approximately two days to incubate, and maintain them selves on the surface of the water in a horizontal position, whilst the ordinary mosquito larvae take up a perpendicular position. Their breathing organs are similar to those of other insects.

Elephantiasis, or the Falaria germ, is transmitted through the agency of mos quitoes, and is a very common disease m some parts of Fiji; being very preva lent in the Lau Group, and very bad in Rotuma. Other places seem to be sin gularly immune, as for instance, from Wainunu downwards, and round the Bua province, where it is a fairly dry cli mate.

The germs, which resemble small thread-worms, invade the blood stream, and cause the swelling of the extremi ties, attacking mostly the legs and arms of the victim. It is as well to keep those who are infected with Falaria well away from your house or bungalow, and iso late them from other labour in your labour lines, or barracks.

The breeding of mosquitoes may be retarded by means of a little petroleum, mixed with tar, poured on the surface of any stagnant water or pools. This should be repeated every fortnight. Most cottages and homesteads are either screened with wire gauze or have a spec ial screened mosquito-proof room, where the family usually congregate after “tif fin”. In spite of one having one’s house built thus, some of the pests manage to gain access when the door is opened.

When there is a plague, it is as well to have a good spray pump ready, with some good insecticide. Mosquitoes per ish much quicker than do flies, or cock roaches, under the spray.

Full protection from the pests can only be had by stocking all stagnant pools and creeks with Gambusia fish which prey on and eats the larvae. There is also the Giant Mosquito, a parasite, and quite harmless, which prevs on all smaller mosquitoes. Itself, it feeds on fruit juices and the sap of various tropi cal trees.

Much has been done to combat mos quitoes by draining, in the Pontine Marshes in Italy, the Canal Zone at Panama, the Singanore Naval Base.

Papua and New Guinea, and by the planting of eucalyptus trees in the first mentioned place and in Ethiopia, and many other places. The planting of these trees is considered to be beneficial and of the first importance, next to swamp-draining.

Miss Margaret Stuckey, of Melbourne, will leave Sydney for Port Moresby. Pa pua, bv the “Tasman” on February 25.

She will be married shortly after arrival to Mr. Stewart Lade, the new head of the L.M.S. school there.

Rev. and Mrs. S. H. Dewdney will ar rive in Sydney from Port Moresby, Pa pua, by the “Tasman” on February 19 to spend furlough. They are stationed at Orokolo. doing mission work for the London Missionary Society.