154 Journal of the Department of Agriculture. 



grass, and not those which sit underneath. The latter would, under 

 the influence of the sun on the bare veld, probably hatch quicker, and 

 when the young- grass shoots up they will be found on the top of this 

 grass. When, however, the burning of ihe grass is undertaken later 

 in the season it would probably destroy the majority of the ticks, 

 and the later the burning is undertaken the better the results would 

 be. Grass burning alone, although carried out in the proper season, 

 will not eradicate ticks ; it only reduces their number. Cattle which 

 graze over the same veld maintain tick-life, and ticks buried in the 

 ground and not affected by fire continue the cycle. 



2. 7)? p7?/w,(/.— Dipping has been made use of and continues to be 

 a very efiicient means of destroying ticks, and undoubtedly it is so 

 wherever it is carried out properly witli a good dip. But dipping 

 can only be effective when the dip reaches the tick. This is not the 

 case with the spinose ear-tick, which on account of its seat in the ear 

 is not reached by the dip. For our purpose we can assume that all 

 ticks will be killed after the dip has reached them. One point must 

 be emphasized, namely, that the death of the ticks as a result of 

 dipping is not always immediate. Female ticks can even continue to 

 lay eggs, although the eggs do not hatch. In arranging the method 

 of dipping the life-cycle of the species of tick with which we wish to 

 deal must be taken into consideration, in order to determine the 

 intervals of the process. 



The blue tick requires three to four weeks for the completion of 

 its life-cycle on an animal. It follows therefore that one dipping 

 within that time, say every third week, is quite sufficient to destroy 

 the crop of ticks collected during that period. The blue-tick larvae 

 on the veld can only live for a certain number of nronths, hardly 

 exceeding eight; within these eight months an animal would 

 constantly pick up these ticks, and by dipping at three-week intervals 

 these would be destroyed. Finally the time would arrive when an 

 animal no longer picks up blue ticks, and the young larvae which have 

 not reached a host will in the meantime have died. Thus dipping 

 every third week to destroy blue ticks will have a certain successful 

 issue, always providing that no tick escapes wetting bj^ the dip. 



Referring to the red tick, we find that in its life-cycle it seeks the 

 host twice — once as larva, from which it moults into a nympha and 

 remains on the host for about sixteen to twenty-one days before 

 dropping; the second time as an adult, the female rernaining on the 

 host from six to ten days. It follows from this that a three-weeklj' 

 dipping M'ould not reach all the stages. In order to accomplish this 

 it would be necessary to dip at least every eighth day. Dipping 

 continued in this way during the period the nymphae, larvae, and 

 adults live in the grass would finally lead to their eradication. 

 Destroying the red tick is very difficult because of its place of attach- 

 ment ; a nympha in the ear or an adult under the tail is protected 

 against dips. Hand-dressing, in addition to dipping, is essential in 

 order to eradicate them completely. 



The Group of the Brown TIeks. — For the completion of their life- 

 cycle they seek the host three times ; as larvae they replete in from 

 three to five days. The same period is required as nymphae, and the 

 adult female requires about a week before it drops engorged to the 

 ground. The quickest results c?m be expected when dipping is 



