Malaria mosquito survey of irrigation areas in the Murray River District / by F.H. Taylor.

  • Taylor, F. H.
Date:
1917
Catalogue details

Licence: Public Domain Mark

Credit: Malaria mosquito survey of irrigation areas in the Murray River District / by F.H. Taylor. Source: Wellcome Collection.

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    In many instances, the distance from residences and obstacles, such as trees, fences, &c., is only a few feet to the breeding place—that is, from the street gutter to the house. In other cases the distance would vary from a few yards up to half-a-mile. ; Large numbers of Culicine larvee were breeding in the swamp near the race-course—larvee of all ages and also pupe. Very large numbers of the adult insects were found sheltering in the long grass. Anopheline larvee, the majority young, were found in small numbers amongst the grass growing in the water at the edges. On no occasion was more than one taken at each dip of the scoop; in some parts of the swamp none at all were found. A small water-hole near by also contained large numbers of Culicine larvee of all ages and pupe. No Anopheline larvee were discovered here. Larvee and pupe of Culicine type were found in the water-tables of Union- street. Larve and pupe of Culex type were very numerous in the water-tables of Allan-street, running east from where the railway line crosses it for about a quarter of a mile. Small numbers of Anopheline larvee of all ages were also encountered in Allan-street, usually a single larva to a dip of the scoop every few feet. These water-tables, on each side of the street, are ideal Anopheline breeding places, being more or less heavily overgrown with docks and other kinds of weeds, which afford excellent protection to the larve and pupe from wind and also good shelter for the adults when hatched. Very few predaceous insects, waterboatmen, &c., were seen in these pools, and, judging by the number of mosquito laryee and pupe found in the pools, are quite negligible. No fish were seen. Few Anopheline larvee were seen in the water-tables of Allan-street, west of the Post Office. Culicone larvee were also scarce, which was probably due to the presence in the water of large numbers of crustaceans—Lepidurus sp. The main irrigation channel, on the west side of the town, was examined for some distance, and none could be found, although the banks were in many places overgrown with reeds extending into the water, affording protection | for larve. This channel runs parallel with Rushworth road for some distance, along which is a ditch, containing muddy water, about a foot deep and five feet wide, which contained large numbers of Culicine larvee, averaging forty larvee and pupe to a dip of the scoop every few feet. Travelling along this drain, in a northerly direction to its dead end, large numbers of Culicone and Anopheline larvee were encountered. The latter were not common, usually only one larva being taken amongst the dead grass on the sides, though occasionally two or three were found at each dip of the scoop. Besides the dead grass on the sides, there were some dead tree branches covered with decaying vegetable matter in the water. Then still proceeding along the main channel for about a quarter of a mile an irrigating channel was seen inside a cultivation paddock, overgrown with weeds and containing numerous small collections of water. These were searched and both Anopheline and Culwcine larvee were found. The former were more numerous than had previously been found, as many as three and .
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