Resistance by the blue tick (Boophilus decoloratus) to the synthetic pyrethroid, fenvalerate

The Shaw larval test, in conjunction with adult tick immersion and stall tests, was utilized to confirm that a field strain of B. decoloratus, from Natal, is highly resistant to the ixodicide fenvalerate (Factor of resistance 4 744). This resistance developed over a reported 18 months of usage for cattle dipping.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

The resistance spectrum shown by a fenvalerate-resistant strain of blue tick (Boophilus decoloratus) to a range of ixodicides

A strain of Boophilus decoloratus, resistant to fenvalerate, was subjected to larval immersion, adult immersion and stall tests using the following classes of ixodicides : organochlorines, organophosphates, a diamidide and pyrethroids. A susceptible reference strain of B. decoloratus was used for comparative purposes. The results indicated a high level of resistance to DDT and camphechlor, slight tolerance to dioxathion, chlorfenvinphos and pirimiphos ethyl, full susceptibility to bromophos ethyl and amitraz, but marked resistance to cyhalothrin, cypermethrin, deltamethrin and flumethrin. This marked resistance in the strain therefore appears to be widespread within the pyrethroid group of chemicals and may have developed as a result of organochlorine cross-resistance.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201