Acaricidal Effect of Practical Crude-extracts of Plants against Tropical Cattle Ticks

Abstract

The acaricidal activity of the plant crude-extracts to tropical cattle ticks were studied in the following plants; Calotropis gigantica R.Br., Calotropis procera R.Br., Cr-ytostegia grandiflora R.Br., Homalonlena aromatica Linn., Kalanchoepinnata Lamk., Pachyrrhizus erosus Lion., Polyscias balfouriana Baill, Rauwolfia serpentina B.K.,Rhinacanthus nasutus Linn., Spilanthes acmella Murr., Streblus aspen Lour., and Thunbergia erecta T. Anders. The crude-extracts of these plants were extracted with 10% ethanol, water, boiling water and boiled water added with the ethanol to 10%. These crude-extracts were tested for the acaricidal activity to the engorged female tropical cattle ticks (Boophilus microplus). Only the crude-extracts of P. erosus with boiling water showed delayed acaricidal activity (anti-laying activity). The crude-extracts obtaining by different times of extraction with boiling water and hot water were stored in refrigerator and tested on both larvae and engorged female ticks with different dilution. The boiling-water and the hot-water crude-extracts for 20 and 40 min. showed high delayed acaricidal activity at 1:6 and 1:5 dilution, respectively. Both of them were stored in refrigerator for 7 days after extraction. The water boiling for 5-40 min. crude-extracts were stored in the refrigerator for 20 days, exhibited relatively high larvicidal activity at 1: 220 dilution. While the hot water extract for 5-40 min. showed high larvicidal activity at 1:220 dilution after storing in the refrigerator for 12 days. This indicates that acaricidal substances of P. erosus (yarn bean) seeds can be easily extracted, and the practical application of this crude-extracts to controlling the tropical cattle tick is expectable.