CLEOME MONOPHYLLA ESSENTIAL OIL AND ITS CONSTITUENTS AS TICK (RHIPICEPHALUS-APPENDICULATUS) AND MAIZE WEEVIL (SITOPHILUS-ZEAMAIS) REPELLENTS

The repellency of the essential oil of the shrub Cleome monophylla (Fa mily: Capparidaceae) and identified constituents of the oil were evalu ated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioas say, the oil of C. monophylla exhibited repellency which, at the highe st dose, was comparable to that of the commercial arthropod repellent N,N-diethyl toluamide (DEET). In a Y-tube olfactometer bioassay, C. mo nophylla oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. 14 Compounds were identifie d in the C. monophylla oil by GC, CC-MS and coinjection with authentic samples. Terpenolene was found to occur in largest quantity (14%) fol lowed by 1-alpha-terpeneol (10%), pentacosane (9%), (alpha + beta)-hum ulene (8%), phytol (5%) and 2-dodecanone (4%). The most repellent comp onents against R. appendiculatus and S. zeamais were 1-alpha-terpeneol and 2-dodecanone. The overall pattern of repellency activity of the C . monophylla constituents with respect to the two arthropods was, howe ver, different. The potential of C. monophylla in tick and maize weevi l control is discussed.