Published online by Cambridge University Press: 10 July 2009
Methods of approach to the control of I. ricinus by acaricidal action are outlined, and the type of acaricide for the control of ticks on dairy stock is discussed.
Dairy cattle were treated against ticks. Arsenic and carbolic washes were avoided for specified causes. The results of using (i) derris (5·5 per cent, rotenone), (ii) 0·5 per cent. DDT, (iii) DDT in a mixture with pyrethrum, talc or kaolin base, and (iv) pyrethrum (0·9 per cent. pyrethrins I and II) in aqueous solution show that (i) had a greater residual toxicity when applied to cattle, (ii) produced erratic results, which at present do not permit of specific recommendations. When DDT is employed in conjunction with pyrethrum as a powder (iii) the effective duration is low, and this is true also of pyrethrum as an aqueous wash (iv).