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This article was published in 1947
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.

The Buffalo Fly

ITS SOUTHWARD ADVANCE AND METHOD OF CONTROL.

H. G. BELSCHNER, D.V.Sc., Deputy Chief. D.A.I., Dept. of Agriculture

The Buffalo Fly, having been checked temporarily by dry seasonal conditions in Southern Queensland, again is increasing. The latest report from Queensland states that the "fly line" now runs from below Bundaberg on the Coast, across to Dalby on the Darling Downs, thence to Miles, across to Roma and up to Injune, then north-west to Hughenden, and then due west to Camooweal. It is anticipated that a small triangular area on the coast, whose base is formed by a line from Brisbane to Dalby and whose apex is at a point near Bundaberg, soon will be fly infested, particularly now that good rains have fallen in that area. Following a visit to Queensland in 1944 to observe the progress of the fly and study methods being adopted to retard its progress, the writer suggested that, in spite of the efforts being made by the Queensland Department to check its progress, the fly would advance steadily down the coast, and inland it would spread along the Mackenzie River on to the Dawson River, and so to Miles, Injune, Roma and the Downs. This is what has happened and it would appear that the fly must enter comparatively soon the North Coast dairying district of New South Wales and will make its appearance in the Tenterfleld Pastures Protection District, and possibly further west. During the winter months of last year, Queensland advised that the fly disappeared over a large area of the country lying between Rockhampton and Maryborough, on the Coast, and as far west as Taroom, in the Dawson Valley.

It would be mere conjecture to suggest the southern boundary of the ultimate distribution of the fly. Entomologists who have studied this aspect and have made forecasts based mainly on the temperature-life cycle curve, have been well out in their calculations.

Whilst there does not appear to be any practical way of averting the spread of this winged insect, certain notable advances have been made in the control of the buffalo fly by Officers of the C.S.I.R., and especially by Mr. K. R. Norris. M.Sc., Officer-In-Charge of buffalo fly investigations at Malanda on the Atherton Tablelands, and also elsewhere in conjunction with the Queensland Department of Agriculture and Stock.

A general account of the life history and biology of the fly and a description of the American horn fly trap for the control of the pest was prepared by Officers of the C.S.I.R. and the Queensland Department of Agriculture and Stock and issued by the Queensland and New South Wales Departments of Agriculture as a pamphlet entitled "The Buffalo Fly and its Control by Means of a Trap." Later, two further informative circulars entitled "Use of D.D.T. to Control the Buffalo Fly" and "A New type of Trap for the Control of the Buffalo Fly" were issued by the C.S.I.R. Quotations from these circulars, especially the one on D.D.T. will be made later in this paper.

Description of the Buffalo Fly.

The Buffalo Fly is a small, dark grey fly, about half the size of the common house fly, and somewhat similar to it in general appearance. The outstanding difference is that the buffalo fly has a sharp piercing proboscis, whereas the housefly has soft mouth parts adapted for licking and incapable of piercing.

The proboscis of the buffalo fly is especially adapted for blood sucking; the flies living on the blood of the host. When resting on a beast, the buffalo fly holds the wings either folded flatly on top of one another over the hinder parts of the body, or else out from the body broad-arrow fashion. In bright sunlight the wings are very irridescent and, under these conditions, can be detected easily on an animal.

If a wind is blowing the flies will be found on the sheltered side of the animal and during rain they move to the lower parts of the beast. Primarily a parasite of the buffalo, the domestic animals most seriously affected in Australia are cattle.

Horses also are attacked commonly, and flies have been seen on pigs, dogs and sheep. They have been known to alight on the backs of slaughtermen and other persons working amongst heavily infested stock, but without causing great inconvenience. The flies quickly return to the cattle; man and animals other than cattle serving only as temporary hosts to the fly which can survive permanently only in areas inhabited by cattle or buffaloes, as it breeds in the dung of these animals.

During the writer's visit to North Queensland, cattle showing grades of infestation from light to heavy were examined. It was noticed that a decided preference was shown by the fly for bulls and stags, and calves were less troubled than mature stock. Pure bred cattle appeared to be more severely attacked than cross-bred cattle.

The flies usually congregate in greatest numbers around the withers and shoulders and on the flanks, but they may be scattered in fair numbers over the neck, ribs and back, and, in small numbers, on other parts of the body and on the legs. On the head and the corners of the eyes are common sites.

At Innisfail a moderate to heavy infestation was seen in a mixed mob of dairy beef cattle put together for inspection. By far the heaviest infestation was on a Devon bull, it being estimated that at least 1000 flies rose from the animal when it was moved, Steers also were heavily infested; the cows showing less severe infestation. The calves were infested only lightly. The reasons for the preference of the fly for certain beasts are not understood fully, but it seems likely that differences in odour may play some part.

Differentiation Between Buffalo Flies and Other Flies Occurring on Cattle.

Stable flies, March flies and bush flies are all larger than the buffalo fly, and the sandfly is much smaller.

There is really only one fly found on cattle with which it might be confused, and that is a small non-biting fly known as Hydrotaea australis. This is a small, dark grey, almost black, fly, about the same size as the buffalo fly, but, of a more robust build.

Whilst the buffalo fly does not walk any great distance on the hide of the beast, flight being by far the more usual means by which the fly travels from place to place on the host. Hydrotaea australis runs around restlessly on the hide. The wings of Hydrotaea australis are not so irridescent as those of the buffalo fly when seen in sunlight, and they also are held at a more acute angle to the body. A close examination with a magnifying glass will show that Hydrotaea australis has a soft retractile sucking proboscis, whilst that of the buffalo fly is erect and stands out from the underside of the head.

Hydrotaea australis is seen frequently in numbers around sores, primarily caused by scratching as a result of buffalo fly irritation. It is also more common on the legs and belly than the buffalo fly.

Life History.

Unlike other bloodsucking flies, such as mosquitoes, march flies and sandflies, which visit cattle only when food is required, the buffalo fly remains on the host throughout the whole of the adult life, leaving the animal only when disturbed or to fly to another animal or for the purpose of laying eggs in bovine dung. In the dung, the stages of the life cycle are passed; the eggs developing into the larva, then to the pupa and finally the adult fly emerges and immediately seeks the host.

The life cycle may be completed in 9 to 11 days in the summer, but may be delayed as long as 46 days or more in the winter. The length of time the flies live on cattle is not known definitely, and appears to vary a good deal. It is probably from 10 to 20 days. Even under favourable conditions the length of life away from the host is about 24 hours only.

Introduction of the Buffalo fly to Australia.

The buffalo fly is said to have been introduced to Australia In 1825, when a number of buffaloes were brought from Timor to the Northern Territory. For many years the fly remained confined to the area around Darwin, and it was not until 1912 that the late Dr. Gilruth, then Ad-ministrator of the Northern Territory, drew attention to the existence of the fly and suggested that it would become a major pest of cattle.

During the next fifteen years the fly spread rapidly as a result of extensive cattle movements, and by 1927 its area of distribution extended from Broome in Western Australia to the western border of Queensland. It crossed into Queensland below Camooweal in 1928.

During subsequent years the distribution of the fly in the northern State has fluctuated a good deal, depending upon rainfall and cattle movement. In dry years, the fly receded almost to the border, but the occurrence of wet seasons in 1939 to 1941 resulted in the fly crossing the low rainfall areas bordering the Gulf of Carpentaria and continuing its progress towards the east coast of Queensland. Once the fly reached the coast it spread rapidly south until it now has reached a point below Bundaberg. In addition to spreading down the coast, the fly also progressed inland from the Mitchell River to the Atherton Tablelands and thence past Charters Towers to Collinsville and, early in 1944 with a wet season, it made rapid southerly progress to Clermont and Emerald, and later to the Darling Downs.

Economic Importance.

The irritation caused by the biting of the flies and the sensation of their presence on the hide is the source of worry to the animals. The actual loss of blood is probably of secondary importance, and as far as is known at present the buffalo fly does not carry any disease.

The cattle toss their heads and switch their tails continuously. They rub themselves against posts and trees and so bring about raw areas on the body which attract other flies. The increased irritation thus caused results in more rubbing, and if the sore areas are in reach of the tongue they frequently are licked vigorously and the rough tongue of the beast retards rather than assists healing.

When the flies attack the corners of the eyes the cattle scratch with the hind hoofs or rub against posts, thus causing sores around the eyes which are characteristic of a buffalo fly infestation.

Other on which sores commonly occur are the shoulders, neck, dewlap underneath the beast. Briefly, sores may be seen on all parts of the body not reached by the tail.

Whilst bulls and steers carry more files than cows, it has been observed that the cows exhibit more raw areas than the other animals.

The Effect of Buffalo fly Attack on Milk Production and Fattening.

The disturbance to feeding and resting and the energy expended by the animal in its efforts to get rid of the flies, and the interference with the grazing of the cattle, would be expected to produce some effects on the well-being of stock.

There is no doubt that fly worry does result in a drop in milk production and in some delay in fattening, but many of the reports as to the extent to which this occurs appear to be exaggerated. Various opinions have been expressed in this connection varying from 15 per cent. to 50 per cent. drop in milk production; to from a few months' to a year's delay in the fattening of beef cattle.

There appears to be as yet no reliable information available on these points and trials are difficult to arrange. Queensland farmers' estimates, on investigation, have been found in many cases to be unreliable and misleading.

In connection with beef cattle, factors such as the lateness in the commencement of the fattening season have not been taken into account when the buffalo fly has been blamed for delaying the fattening of cattle.

Whilst discussing this subject with a pastoral Inspector for Vesty's, who was formerly Manager of Wave Hill Station, he stated that he would sooner have the buffalo fly for nine months than sand flies for one month. He said. "Sand flies scatter the cattle and keep them walking, thus keeping their condition down. Buffalo flies don't scatter the cattle to any extent. They cause sores about the eyes and dewlap and on other parts of the body, but the condition of the station cattle is not severely affected." He went on to say that they have had the buffalo fly on Wave Hill for many years, but do not regard it as a serious station worry. It is a seasonal infestation, more severe in humid weather. Cattle tick infestation a far greater menace." In connection with this statement, it is pointed out that Wave Hill Station is open downs country and is unsuitable for buffalo fly propagation, The dung dries out quickly and the cattle are spread over a wide area.

A cattle fattener at Innisfall considered that the buffalo fly delayed the fattening of his cattle by a season. He was unable to supply satisfactory information as to variation in the feed and the effect of cattle tick infestation, which was severe, in delaying the fattening of his cattle.

A dairy farmer on the Atherton Tablelands considered that fly worry had reduced the output from his dairy herd by 50 per cent. From observations made on the farm, including inspection of the pasture and methods of management, it is considered that the statement is somewhat misleading.

There is some evidence that beef cattle exposed to infection over a period of years develop a certain degree of tolerance to the buffalo fly.

An additional source of trouble with dairy cattle is the restlessness of infested dairy cows during milking. Horses and working bullocks are difficult to handle when buffalo flies are numerous.

Range of Flight of Buffalo Fly. There is as yet no reliable information available on the range of flight of the fly. Some work has been carried out by the C.S. & I.R. on the extent to which flies may travel from one property to another but difficulty has been experienced in the marking of the liberated flies. Further work is in progress and different methods of marking the flies are being adopted.

Flies found on Palm Island, 20 miles off the coast from Townsville, are believed, after the closest enquiry, to have arrived there on the wing, probably assisted by wind.

Methods of Control.

Prior to 1942-43, when the buffalo fly reached the east coast of Queensland, the distribution of the fly in Australia was restricted to the northern part devoted to the raising of beef cattle. In these areas the size of the holdings and the infrequency of mustering rendered the application of control measures impossible. Good work was done, however, by the Queensland Department of Agriculture and Stock in retarding the progress of the fly by spraying all cattle being railed south or east and by regulations controlling the movement of cattle. Double spraying at railhead—one before entrucking and the other in the trucks—with a phenolic medicament has been the usual practice. The aim has been to drive the flies off temporarily and to move the train off quickly, preferably leaving a few unsprayed cattle in the yards as decoys.

Whilst considerable success was achieved by this method of spraying in preventing movement of the buffalo fly by rail whilst the fly was confined to the beef cattle country, it was not so successful once the fly reached the Queensland Coast, and it can be said that spray plants erected at rail heads along the Queensland coast, ahead of the fly, have had little effect in retarding its advance. The main reason for this appears to be the closer cattle population on the coast. The opinion has been expressed that the travelling of cattle by rail through sheep country, after having been sprayed at railheads, may have contributed largely to the success of this method of control in the past, and that "carry over" flies probably are blown away whilst cattle are travelling in the roofless, Queensland cattle trucks.

Possibility of Spraying Cattle on Queensland-N.S.W. Border.

The possibility of spraying railed cattle on the northern border of New South Wales or in close proximity thereto (Wallangarra or Tentertield) with the object perhaps of retarding progress of the fly south by rail, has been explored. The difficulties are considerable, mainly due to the time it takes to load a train of cattle (three to four hours), which would render spraying prior to trucking with the phenolic medicament used in Queensland ineffective, as the flies would be back on the cattle first loaded before the train moved off. Spraying of cattle in trucks by the Queensland method is impracticable, because all New South Wales cattle waggons are covered, thus preventing overhead spraying from a gantry at the side of railway line.

Action has been taken, however, to build platforms alongside the cattle loading ramps at Wallangarra and Tenterfleld, from which cattle will be sprayed in the trucks, over their backs, with a D.D.T. mixture; by means of a jetting outfit with special nozzle. Once the fly reaches the border, all cattle travelling south by rail will be so treated at these trucking points.

Such attempt to treat cattle on rail will check only temporarily the advance of the fly, but it may prevent the fly being carried some hundreds of miles south on the trucked cattle. Once the fly reaches the border, it will infect local cattle and pass from property to property and the more closely settled the district, the more rapidly the fly will spread; subject, of course, to suitable climatic conditions.

Control by Means of a Trap.

A trap based on the American Horn Fly trap has been well tested out in Queensland. In a pamphlet prepared by the Council for Scientific and Industrial Research, and issued by the Queensland and N.S.W. Departments of Agriculture, a description is given of the construction and use of this trap, which is reported as being effective in keeping the buffalo fly down to an insignificant level on dairy farms and thus reducing the incidence of sore areas and fly worry.

The trap is built into the fence of the milking yards or other convenient place where the herd may use it instead of a gate as the cattle pass through to and from milking. Drapings inside the trap brush off the flies, which fly towards the light and are caught in gauze wire trapping boxes arranged on each side of the trap. As the flies usually die in 24 hours it is not necessary to use any spray to destroy them. The traps are automatic in their action and need very little upkeep. These traps have been seen in operation in Northern Queensland, where it was observed that dairy cattle pass through them without any trouble. On one dairy farm visited, the trap had been found to reduce the fly infestation on the cattle from approximately several hundred flies on the cows and 2,000 flies on the bull to 20 flies per cow and 200 on the bull after the trap had been in operation three weeks.

The fly population is so great when trapping first commences, while there is continual emergence of young flies from the dung, that it takes at least three weeks for the effect of trapping to be shown. Further, it takes about three weeks before the animals are trained properly to go through the trap with all the drapings in place. However, even before all the drapings are in place thousands of flies will be caught daily in the trap. Reports from the C.S.I.R. Officers in Queensland state that it is quite common for the fly population to be reduced to a dozen or so flies per cow on dairy farms where traps are in operation.

Whilst these traps are of definite value in protecting the milking cows which pass through them two to four times a day, a difficulty occurs with dry stock, and also the bull if he is kept separate from the herd. A trap might be placed in a suitable position, such as on the way to water, to deal with dry stock, much depending on the layout of the farm. The cattle must be trained to go through the trap, but this is arranged easily by allowing them to go through the trap for a few days without any drapings which can be added one by one each day until the animals are quite familiar with them and pass through as they would through an open gateway.

It is obvious that these traps will be suitable only on dairy farms or small fattening properties, or with quiet stud cattle. On larger properties, particularly where numbers of beef cattle are bred, the traps naturally cannot be used.

Cost of the Traps.

The traps can be obtained for approximately £30 ready built and complete with gauze trapping boxes. The framework, however, can be built more cheaply on the farm and the trapping boxes purchased separately. Demonstration traps may be seen at Wollongbar and Grafton Experiment Farms, on the property of Mr. A. C. Pratt at Tweed Heads, and at Murwillumbah and Mullumbimby.

Glass Type Traps.

A new type of trap has been evolved and tested out with satisfactory results. In place of the gauze trapping boxes on either side of trap, glass is used and glass also is incorporated in the roof. A four per cent. to five per cent. solution of D.D.T. in power kerosene is sprayed on to the inside of the glass of the passageway and roof. When the kerosene has evaporated a second coat is applied to ensure a more even and heavy deposit. About a pint of solution will coat the glass with sufficient D.D.T. to last two months. The flies are brushed off in the usual way by the drapings, but instead of being caught in the gauze boxes, merely buzz around on the glass and so acquire a lethal dose of D.D.T.

Use of D.D.T. (Dichlore-diphenyl-trichlorethane).

The following information is quoted from circular issued by the C.S. & I.R.:—

D.D.T. is a highly persistent contact poison, not a repellent. Flies that rest for even a short time on the skin of cattle treated with this material eventually die, but they do so slowly. This action may continue for weeks after application of D.D.T. and any flies alighting on the cattle during this period will be killed.

As the buffalo flies move rapidly from place to place on the body of the beast, it Is not necessary to spray the animal all over as the flies eventually alight on areas that have been sprayed. It is desirable to spray those parts of the body that are especially favoured by the flies, such as the shoulders and flanks.

Control may be effected if only half of the cattle in a herd are sprayed, because the flies move from one beast to another and so sooner or later settle on treated hair.

Toxicity.

D.D.T. is a poison and must be handled with care. The question of the possible toxicity to cattle is still under investigation, but there is reason to believe that it is not more dangerous than other insecticides, such as arsenical dips. The main points to be observed when using D.D.T. for spraying cattle are:—

(1) To avoid as far as possible allowing solutions or emulsions to come in contact with the skin.

(2) After spraying, wash the hands or any other contaminated parts of the body thoroughly.

(3) Be particularly careful not to allow stock solutions to come in contact with the skin.

(4) When spraying cows in the bails, see that no D.D.T. is transferred to the milk. This can best be achieved by keeping milk buckets well away from the mist when spraying, and by ensuring that the udder does not become contaminated by the material.

Use of D.D.T. Spray on Dairy Cattle.

Whilst the Buffalo Fly can be kept well under control by the use of the traps already described, nevertheless it may be necessary to supplement these traps by the use of D.D.T. sprays on cattle that are not running with the milking herd. Further, if for any reason buffalo fly traps cannot be used, the periodical use of D.D.T. sprays may be substituted.

According to the circumstances, the D.D.T. may be applied in emulsions or solutions.

(1) D.D.T. Emulsions.

When the object is to protect the cattle as long as possible, D.D.T. emulsions should be used. It has been found in the experimental work carried out by the C.S. & I.R. that emulsions containing four per cent. D.D.T., when applied at the rate of one gallon to eighty head of cattle, will kill all flies that alight on the cattle for a period of about two weeks, after which the toxicity falls off rapidly. The cows should be treated again alter the fly population begins to build up. The cows may be treated in the bails or in a crush, using a powerful continuous spray hand-atomiser. Small household type sprays are not suitable and will rust rapidly if emulsions are used in them.

An area of skin about 18 inches in length and extending down both sides for about 12 inches from the withers should be saturated with the spray.

Experiments carried out with many different emulsions suggest good results can be obtained with any emulsion containing four per cent. D.D.T., but care must be taken to use a solvent that is not harmful to cattle. Unfortunately, many good solvents of D.D T. when placed on the skin of cattle cause severe irritation or even burning. The following are examples of simple, readily prepared emulsions that in tests have produced little or no irritation on the skin of cattle:—

(a) D.D.T. (90% pure) 1 lb.
Eucalyptus dives oil (type) 3½ pints
"Wetsit" ¼ pint
Water to make 2½ gallons of emulsion.
(b) D.D.T. (90% pure) 1 lb.
Solvent naptha (boiling range 90º-190ºC) 5 pints
"Wetsit" ½ pint
Water to make 2½ gallons of emulsion.
(c) D.D.T. (90% pure) 1 lb.
Power kerosene 1 gallon
"Wetsit" ¾ pint
Water to make 2½ gallons of emulsion.

"Wetsit" is an emulsifier and wetting agent; doubtless there are others which would prove effective. It is mentioned because it happens to be the one with which the C.S. & I.R investigators have had most experience.

To Prepare the Emulsion.

First make a stock solution by dissolving the D.D.T. in the solvent (eucalyptus oil, solvent naptha or power kerosene) and then adding the "Wetsit." This stock solution is a clear, stable solution which can be stored for long periods without deterioration.

The emulsion is made by first adding to the stock solution an approximately equal quantity of water whilst stirring vigorously until a uniformly milky fluid is obtained, and then adding the remaining water, while still stirring, to give the proportions according to the formulae.

It is recommended that only sufficient emulsion for immediate use should be prepared. The emulsion should not be stored, only the stock solution.

(2) D.D.T. Solutions.

The C.S. & I.R. reports that good control has been obtained by using solutions of four per cent. D.D.T. in power kerosene (1lb. of D.D.T. in power kerosene to make 2½ gallons of spray) and applying this as a fine mist to infested cattle in the bails.

Two pints of this solution are said to be sufficient to protect a herd of thirty cows for more than a month. The solution should be stored in glass vessels.

This method has the advantage of simplicity and cheapness, but the persistency of the toxic effects is said not to be as great as with the emulsions, for far less D.D.T. is applied to the animals. Consequently the cattle may have to be sprayed more frequently. There is also more danger of contaminating the milk.

As kerosene is harmful if applied directly to the skin of cattle, the atomiser used should produce a fine mist that will not penetrate the skin, but merely leave a light deposit on the surface of the coat. For this purpose, the ordinary household pusher type of atomiser is most saUsfactory.

Whenever a cow bearing a considerable number of flies is brought into the bails, a few puffs of the spray should be directed on to the beast where the flies cluster most thickly. Generally this is the shoulders and flanks. All flies caught in the mist of the spray will die; those that are missed by the spray are killed later when they alight on the treated areas and come in contact with the D.D.T. that has remained sticking to the hair after the evaporation of the kerosene. By this method it is stated the numbers of flies can be kept down to a very low level. The exact degree of control attained naturally is dependent on the frequency and thoroughness of spraying, but if a few of the most heavily infested cows are sprayed every day or so, the mean number of flies generally can be kept down to less than a dozen.

The initial reduction of a gross infestation requires the spraying of most of the cows, but once the population has been reduced, the amount of spraying required to keep it down is said to be not excessive.

D.D.T. Milk Contamination Tests

D.D.T milk contamination tests using a four per cent. solution of D.D.T in kerosene, have been carried out at Grafton Experiment Farm.

Thirty head of dairy cattle were sprayed during milking, immediately after each cow had been milked and while they were still in the bails. The times of spraying were as follows:-

20/1/1947— 3p.m.
22/1/1947— 3p.m.
23/1/1947—3p.m.
24/1/1947—6 p.m.

The cream from this dairy was arranged so that each day's supply was delivered to the factory in separate containers on ordinary re-ceiving days, viz., Monday, Wednesday and Friday, where it was graded carefully by the Senior Dairy Instructor and the Factory grader.

The trial proved quite satisfactory from a quality point of view, there being found no trace whatsoever of any foreign flavour. A similar test was carried out some six months previously, with similar results.

Use of D.D.T. Spray on Beef Cattle.

As beef cattle (and dry dairy cows) are handled infrequently, a single treatment with D.D.T. must be made to last as long as possible. The four per cent. solution of D.D.T. in power kerosene and the method described for its use with milkers is not practicable.

An emulsion is recommended for beef cattle, which should be mus-tered and sprayed in a crush over an area of several square feet on the shoulders. Mustering for dipping provides a convenient opportunity for spraying cattle with D.D.T. After passing through the arsenical dip and allowed to drain the cattle may be crushed and sprayed. Strong continuous-spray hand atomisers or a knapsack spray may be used.

D.D.T. Emulsions in Dipping Vats.

The use of D.D.T. emulsions in dipping vats cannot be recommended because the emulsions break clown in the bath. This means that a large quantity of D.D.T., left after dipping a mob of cattle, almost certainly will be lost. Further, the quantity of solvent necessary for charging a dipping vat is very great—for example, in order to charge a 2000-gallon dipping vat with a two per cent. D.D.T. emulsion, about 400 gallons of solvent would be required.

A proprietary preparation known as "Rucide" appears to be the answer to a D.D.T. solution in a dipping bath. "Rucide" contains 60 per cent. para-para isomer of D.D.T. and incorporates also a "Solubulizer," which causes the material, on being melted and poured into water, to form a colloidal solution, which gradually turns into a fine and relatively stable solution of D.D.T. particles. This preparation has been tested out by Officers of the C.S. & I.R. in Queensland with satisfactory results, and the official reports indicate that this preparation represents a distinct advance in the utilisation of D.D.T. The tests showed that cattle dipped in a one per cent. solution of this mixture remained practically free of buffalo fly for six weeks, with complete protection for 14 days.

The difficulty with D.D.T. solutions in dipping vats is the analysis of the fluid in the bath to see if it is maintaining its strength or is varying. Industrial chemists responsible for the production of "Rucide" now claim they have evolved a technique for analysing samples of "Rucide" dips. "Rucide" also has been tested out against cattle ticks, but, although found to be very effective, did not bring about 100 per cent. kill. For this reason, whilst of value in the control of cattle tick in Queensland, where it is not desired at present to eradicate tick, the use of this mixture cannot at present supersede the arsenical dip in New South Wales, where eradication plans are in progress.

In the trials conducted in Queensland the cost of dipping cattle with this proprietary preparation worked out at just under sixpence a head. The preparation can be used very effectively as a spray for buffalo fly, when the cost of treatment is much lower.

Still another material Gammexane (666), looks very promising as a spray or incorporated in a dip for the control of buffalo fly. This is still in the experimental stage.

The advent of safe and efficient sprays makes the outlook for the control of the fly, when it reaches here, much brighter; while it certainly would appear that sufficient control of the fly population can be brought about to prevent interference with production.

 


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