application to the hair coat of domestic animals. Cattle can be immersed in dip-baths containing dipwash, or soaked using a pressurized spray-race made of metal tubing and nozzles. Sheep can be treated in smaller dips or showers. Acaricides can be applied to dogs in watery shampoo formulations. Acaricide active ingredients are usually soluble in oil. This makes them suitable for concentrated oily formulations which spread from a pour-on applicator over the hair coat. Alternatively, some acaricides are incorporated in polyvinylchoride plastic ear tags for cattle, or collars for dogs. Modern acaricides belong to the general classes of organophosphates (example chlorfenvinphos), formamidines (example amitraz), synthetic pyrethroids (example flumethrin), phenylpyrazoles (example fipronil), and benzylphenyl ureas (example fluazuron).[2] When correctly applied, they can be highly effective. Problems with acaricides are: danger of acute poisoning of treated animals and human staff; residues contaminating meat and milk; environmental contamination especially water sources; resistance that ticks acquire to acaricides; and cost of application. Cost and contamination can be reduced by seasonal timing of application (strategic treatment) based on ecological knowledge. Prediction of best times for treatment can be made using computerized models of the population dynamics of ticks. Botanical acaricides Farmers lacking access to, or sufficient cash for, manufactured synthetic acaricides often use various herbal treatments, locally available. Nicotine from treated tobacco leaf is an example, but such unregistered preparations require careful use to avoid poisoning or skin damage. Commercially formulated botanical acaricide may often be available in tropical regions, containing the active ingredient azadirachtin. This is extracted as neem oil from fruits and seeds from the neem tree, Azadirachta indica. Eradication of ticks Eradication of ticks, as total removal of all populations of a species over a wide geographical area defined by natural boundaries, has been attempted several times. In the southern states of the USA the tick then known as Boophilus annulatus (Rhipicephalus annulatus) was eradicated for the purpose of control of babesiosis in cattle. The eradication was successful after more than 50 years of control with much emphasis on dipping in chemical acaricides. The tick was eradicated up to the border of USA with Mexico, and a control and quarantine zone remains in place there. Similar efforts were made to eradicate the tick then known as Boophilus microplus (also a Rhipicephalus, Rhipicephalus microplus) from New South Wales, Australia. However, this failed, partly due to the difficulty of maintaining a barrier against invasions from