Some Aspects Of New Dipping Materials

Press, Volume C, Issue 29638, 7 October 1961, Page 6

Some Aspects Of New Dipping Materials

A great many farmers will regret the need for the withdrawal of Dieldrin and Aldrin-based dipping materials because they have been exceptionally easy to use and highly efficient in most cases for the purposes for which they were supplied, but most thinking farmers will be ready to accept their passing in the interests of the purity of New Zealand meat exports, even if the use of the new materials now available involves more care and possibly increased cost. 14 Because farmers generally so far know very little about the new materials based on organic phosphates that are being offered for sale this dipping season with official approval, this newspaper has asked some of the principal suppliers of these products to provide information which may be helpful to farmers in their approach to them.

The erganic phosphate materials on the approved list are Asuntol iCo-Ral), Delnav (Hercules 528), Diazinon and Nankor tßonnel).

Asuntol Information supplied Through Henry H. York and Co., Pty., Ltd. This material will be marketed in New Zealand under the name Asuntol. It is made by a well-known German firm and is used in America as Co-Ral. in South America. Europe. Africa and Australia. It is recommended for use only for plunge and shower dipping with the most favourable period for use being six weeks after shearing. Bert results are obtained when there is saturation right down to the skin and because it is very stable in the wool good protection is claimed. Asuntol can be used at two strengths. Half a pound in 100 gallons of water eradicates lice and keds and gives short term blowfly protection depending on environment. At lib to 100 gallons lice and keds are eradicated and there is long term blowfly protection. the length of which is again dependent on environ, ment. It is reputed to be very stable in the bath with no r stripping effect, so that when topping up no reinforcing in strength is required. It is claimed to be the most economical of the organo phosphorus materials available. In addition to being highly effective against lice and keds and giving good blowfly protection, depending on con. centration and environment, it is also highly effective against the native cattle tick. Diazinon Information supplied through Ivon Watkins, Ltd.: Diazinon has been used by many farmers in New Zealand in the last five years and much longer in Australia where last year more than 100 m sheep were treated with it. It was developed by scientists of the Geigy organisation who had specifically in mind an insecticide that would remain stable under all kinds of conditions, that would control resistant strains of insects and which would be safe in its action.

Diazinon will kill all stages of lice 'very rapidly and give protection from reinfeslation from stray and lousy sheep. The action on keds parallels that on lice. It sterlises the pupa of the ked and acts rapidly on the adult. In its action against blowflies, including the resistant strains, it gives long periods of protection against both body and crutch strike. One of its specific purposes has been to kill insects which have developed resistance to other chemicals. The fact that it is effective at low concentrate rates reduces the likelihood of resistance developing. Experience in Australia has shown that the use of Diazinon prevents the spread of infestation in flocks lightly infested with itch mite.

The effectiveness in general of Diazinon on sheep depends largely on the important capacity of the insecticide for absorption by the wool grease and its ability to move down the staple into the eve? increasing growth of wool beneath. It is held entirely in the wool wax and not in the fibre. On application to the staple it diffuses into the follicle and into the wax coating the new wool as it grows This explains the basic reason for the long ence of Diazinon. To complete the cycle it acts quickly on both larval and adult forms of insect life so that populations are reduced before they have time tq multiply. Sheepfarmers will find that no change from the normal methods of treatment is necessary. Diazinon is available for plunge dips, shower dips, for tip spraying, for dusting and as a jetting fluid.

Diazinon And Delnav Information provided through Cooper, McDougall and Robertson (N.Z.) Ltd.: Delnav and Diazinon will be offered for plunge and shower dipping and Diazinon only for spray race treatment.

Diazinon if correctly used through a spray race will provide worthwhile fly protection, but whereas Dieldrin gives about the same protection by spray race application as it does by dipping, Diazinon gives less protection when applied as a spray. Provided the spray races will

give adequate coverage of the -crutch area then the lower concentrations, recommended by us should provide short term protection (about a month» and the higher conqewtrations should provide up to two months’ protec! ion. Under conditions of heavy strike the period of protection will be shorter. Preventive control of blowfly by spray race treatment should therefore be delayed until as near as possible to the actual incidence of strike. Even then a small percentage of strike can occur within two weeks of treatment if coverage is inadequate. High concentrations will not compensate fbr inadequate coverage.

For maximum periods of protection and prolonged blowfly control bo'h Delnav and Diazinon demand methods of application which provide saturation of the skin surface. This means plunge, dipping, shower dipping or jetting to saturation. In this case up to six weeks’ protection may be obtained at the lower concentration and up to three months with the higher recommended concentrations.

Using either plunge dipping or showers, both insecticides will give 100 per cent, control of keds and lice and prolonged reinfestation protection against each.

Early in controlled spray race trials with organic phosphates we quickly found

that lice were more difficult to control than keds. Exactly the opposite applied with Dieldrin. The organic phosphates will not, from a lice angle, tolerate the same degree of wool growth at treatment as did Dieldrin. Diazinon at recommended spray race concentrations will normally give 100 per cent, control of lice with up to three months wool growth on the sheep at the time of treatment, but if wool growth is greater than this there is a risk that complete lice control will not be obtained. Where eradication is desired a farmer should aim at treatment with a maximum of six weeks’ wool growth. This applies for keds and lice even if it means retreatment for fly at a time nearer the peak fly incidence. Where pre-lamb shearing is practised this certainly applies.

Delnav is less efficient than Diazinon when the two are used through spray races against lice and it is doubtful if Delnav will tolerate even six weeks’ wool growth. It is for this reason that we are not offering Delnav or any other organo phosphate other than Diazinon for use iri a spray race.

Nankor Information provided through Farm Chemicals Company: Nankor is marketed under the trade, names Tartan, Grenol and Vetemac. It has been field tested in New Zealand for three years. It is a chemical of extremely low toxicity to man and animals. In the United States. Nankor has been approved tor treatment of external parasites of eattle, pigs, sheep and poultry. It is also approved for internal application to cattle for control of eattle grubs.

For the current season it is available in New Zealand in the form of powder dips for plunge and shower dips, sheep dust, tip spraying fluid, jetting solution and fleece dust for hand treatment. Recommendations for its use are:

Plunge and- shower dipping; Powder dip containing 25 per cent. Nankor. For initial changing of the dip use one carton (31b Nankor plus bactericide) to each 200 gallons of water. Replenishment and topping up should be given close attention as detailed on labels. Approximate cost 6d a sheep. Dusting with pressure dusting machine: Micronised sheep dust 4 per cent. Nankor. The optimum dosage for sheep dust is about 10 to 12 sheep treated per lb ot dust. Treatment within three months of shearing. Approximate cost 3d a sheep. Tip Spraying Tip spraying with a spray race: Sheepspray concentrate containing 32 per cent. Nankor. Treatment to be carried out within three months of shearing. For keds and lice control only within three months of shearing use two pints to 40 gallons of water. Approximate cost 2d a sheep. For keds. lice and protection against fly strike within three months of shearing use four pints to 40 gallons of water. Approximate cost 4d a sheep. Attention should be given to label recommendations for tip sprayers with an output greater than 300 gallons of water a minute.

Jetting and hand dusting with Nankor for extended fly protection should be carried out according to label instructions. Approximate cost 2d to 3d a sheep.

General recommendations: Greater attention will have to be given to the long standing law of dipping within three months of shearing. Off-shears tip spraying or dusting has become increasingly popular among farmers and is a convenient time for this to be done. Four Weeks after shearing is perhaps the best time to dip as by this time shearing cuts have healed and there is an ideal length of wool in which the maximum amount of chemical can be retained. If fly strike is prevalent in your area dip or dust again just prior to the onset of the strike period. If possible

sheep should be kept clean at all times as it is too much to. expect any chemical to persist in the presence of dags and dirt.