PESTS-NOT PETS

Evening Post, Volume CIX, Issue 5, 7 January 1930, Page 8

PESTS-NOT PETS

MOSQUITO MENACE

ERADICATION A DUTY

"Mosquitoes are pests—not pets."

Although Mr. David H. Graham, who was for three years research officer of the Mosquito Besearch Committee in Auckland, has not seen any mosquitoes in Dunedin, he issues a warning to .the people to treat them as unnecessary pests, and not as pets, states, the "Star." By allowing water to lie about in pools and in empty tins and tires and other receptacles, the public cultivate the mosquito as a pet. "I have not seen a mosquito yet in Dunedin," said Mr. Graham to a '' Star reporter at the Portobello Marine Eesearch Station on Monday. Mr. Graham is now in charge of the biological work at Pdrtobello, and he said he would be very pleased if people who caught mosquitoes would send them to him. Specimens in either the larva or adult stage are sought after. by Mr. Graham, who anticipates that he will be able to study the mosquito problem in his spare time from the station. HOW TO GET SID OF THEM. For over ninety hours a week for three years Mr. Graham studied the mosquitoes in the Auckland district, and he discovered ten specimens, and traced their life'history. The mosquito menace is a serious one, and on two boats from the East—the Sussex and the Narbada —Mr. Graham found malarial mosquitoes. It was easy for the disease-carrying pests to fly out of the cabins and holds of the Eastern vessels, said Mr. Graham, and the first step to prevent disease was to remove the cause. To rid New Zealand of mosquitoes would be a simple matter, although not necessarily easy. If everybody worked a little the country would soon be freed of them. The general problem of mosquito control was solved long ago, and his investigations in various parts of the Dominion into the breeding and life habits of the pests showed how the control could be exercised. "We call the mosquito a nuisance because it bites, but perhaps we dislike it chiefly because it keeps us awake at night by its persistent singing. But it is more than a nuisance. It is a real danger to health, for, apart from loss of rest, many people suffer severe pain and serious illness from the effects of mosquito bites. We have at leapt ten species of mosquitoes breeding in Now Zealand. The total number of distinct species in the world is over 1400, and many more new- ones are still being found. Of the New Zealand ones some are essentially household or domestic pests." ' Mr. Graham has found that some of the New Zealand mosquitoes live in fields near drains or in swamps. Other kinds are found only in the bush, and at least two varieties only frequent the seashore. Three varieties he found infested houses and habitations, _ only two of which were troublesome in the country. One bit at night only, another, confined to the city, bit only by day, but the third, which lived in the country, made up for it by biting both day and night. It was much smaller $han the other two. PEOPLE THEMSELVES , RESPONSIBLE. From the tenement owner to tho Government Mr. Graham traced the responsibility of tho people for their own mosquito troubles. In the water left in a kerosene or petrol tin 2000 to 3000 mosquitoes would breed every three weeks, while '250 mosquitoes would be bred in a jam tin in the same period. Every tin in a garden or yard was a potential source of disease and nuisance. In industrial Auckland he had found very few premises, or even warehouses, where backyards were quite clear of water holding, and therefore mosquito-breeding rubbish. But the premises of private individuals were not the only offenders. The areas under the control of the Government, local bodies, and harbour boards, such as dumps, required very careful observation. Country residents, with their rain- water tanks and troughs and unattended pools in the fields, helped tho mosquito to breed in enormous numbers. "When one realises that a jam or milk tin or bottle holding a few ounces of water will breed hundreds of mosquitoes every three weeks, and an unattended petrol tin with a gallon of water breeds thousands in the same time, it behoves us all to do our little bit," said Mr. Graham. "If every owner of a back yard or vacant section, each foreman of industrial and commercial houses, each local body inspector or officer responsible for harbour board and Government areas did his small share in destroying these unnecessary water-holding containers or iii treating those which be destroyed with oil or disinfectant, 95 per cent, of these mosquitoes would disappear. And there would also be less harbourage for rats." The bite from the mosquito was really a pricking by a set of fine needles or lancos, carried in the proboscis or sheath projecting from the head. It was the female that bit, and she bit in order to get human or animal blood, which seemed to b» necessary before. she could lay eggs. Mosquitoes must have water for breeding and the development of the early stages. The oggs were laid on the water, and from these eggs the larvae or wrigglers were hatched. Although it lived in water, the wriggler breathed air, for which purpose it had a longish tube or siphon, which looked very much like a tail. The wriggler was the feeding and growing stage. Then followed a resting stage called the pupa, in which the legs, wings, and other parts of the adult were formed. The pupa finally came to the surface, tho skin opened along tho back, and the full-grown mosquito climbs out. "CAUSE SHOULD BE REMOVED." To keep mosquitoes. away, Mr. Graham recommended oil of citronella, but for bites he said, ordinary soap could be used. Tho preventive was of little use. The cause should be removed. He had known women to be paralysed in the legs by being bitten while sitting on porches in Auckland, and intense pain had been caused thousands of other people. Stock of all descriptions were also troubled by the pests in the Par North. An ounce of kerosene on 15 square feet of water would kill all tho larvae. Tanks were tho principal breeding places in the country, and ho recommended that olive oil should be sprinkled in a film over the tanks after every rainfall. Olive oil would not taint the water, but once the surface was broken a fresh issue of oil would have to be applied. Discussing the malarial mosquitoes found on the Eastern boats, Mr. Graham said he did not think they would live in Otago owing to the colder weather. Mr. Graham has already issued one scientific paper on mosquitoes of Auckland for the New Zealand Institute, and he has a paper covering four species ready for the publishers. A few days ago a silvered halfpenny was passed at the ticket box of one of the Timaru picture theatres in payment for a shilling ticket. Apparently ,tho person responsible for the imposition desired to start the new year with a clear conscience as the manager of the theatre has received by post 11J in stamps as "conscience money." ■