| dc.description.abstract | The objectives of this study were to determine the toxicity of
M. volkensii plant extract on the larvae, nymphae and adult
Rhipicephalus appendiculatus ticks and to compare the effects with
those of the ticks treated with Pyrethrum and Azadirachtin plant
extracts. The effects of the plant extracts on the oviposition and
hatchability of Boophilus decoloratus female ticks was also
determined.
The larvae and nymphae were treated with the extracts using
the larval packet test whereby unfed larvae and nymphae were placed
in filter paper packets which were impregnated with an oil
preparation of the plant extracts. The adult ticks were dipped in
different concentrations of the plant extracts using the emmersion
technique.
Significant mortalities (p<0.05) were observed in the treated
unfed larvae of R. appendiculatus. The concentration that killed
50% of the treated ticks (LCso) by the extracts was analysed and the
results indicates that among the
natural products, neem powder
performed better (LCso, 1.26g/1) than pyrethrum extract (LCso,
1.95g/1) and M. volkensii (LCso, 2.68g/1) . The results were also
compared to Cubex which is an enzyme and SteladoneR which is a
standard commercial Organophosphorus acaricide.
The oviposition and egg hatchability of B. decoloratus treated
with the three extracts was significantly (P<0.05) reduced and at
similar concentration the relative potency of the extracts was,
M. volkensii 0.057g>Pyrethrum,O.085g>Neem powder,O.089g>control
0.152g, with M. volkensii reducing the potential
reproduction of B. decoloratus by 94% at a high concentration of
100g/l. There was a decrease in the acaricidal activity of the
plant extracts against nymphae and adults with the lowest
sensitivity being found in the adult ticks. However, when M.
volkensii extract was injected at 500~g/tick, into the engorged
tick haemolymph, the adult R.appendiculatus ticks were more
sensitive and died 4 hrs after the treatment.
Natural products from Melia volkensii, Azadirachta Indica and
Chrysanthemum Cinerariafolium plant extracts have strong acaricidal
activity against Rhipicephalus appendiculatus and Boophilus
decoloratus ticks.
From this data, it is concluded that all the three plant
extracts are suitable for use in an integrated tick control
programme but the use of M. volkensii and neem extracts is limited
by their low solubility in water and their less penetration across »
the tick cuticle. | en |
