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Abstract
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One of the important effects of plants extracts and essential oils on insect’s
behaviour is repellent activity that has a potential for utilization in pest management
programs [1]. In this study, polar and non-polar extracts of some medicinal plants
including Ageratum houstonianum (Mill.), Xanthium strumarium (L.), Achillea
millefolium, Marrubium vulgare, Ranunculus repens, Delphinium linearilobum and
Cupressus arizonica were prepared using maceration method. Choice test method was
conducted for comparing repellent activity. A standard rectangle Plexiglas (27×11 cm)
was used for tests. Artificial diet on the peace of filter paper containing 500 microliters
of each extract in three concentrations (0.05, 0.025 and 0.125 mg/ml) were replaced in
opposite position with non-treated artificial diet as control. Presence of 2nd larval instars
of Spodoptera exigua around the test and control area were recorded each 1,6,24 and 48
hrs. The results revealed that with increasing the concentration of extracts repellent
activity increased. The hexane extract of A. houstonianum showed non repellent activity.
Acetone extract of X. strumarium compeletelly repeled the insects specially in
concentration of 0.05 mg/ml. Hexane extract of X. strumarium and ethil acetat extrac of
M. vulgare showed 88.88 and 90.75% repelent activity after 48 hours respectivily. Ethyl
acetat extrac of A. millefolium and ethanol extract of D. linearilobum showed 75 and
80.5% repelency against 2nd larval instars of S. exiguae respectivily. In over all we thing
that medicinal plants with affecting the behaviour of insects could use in IPM programs
in addition with their advantage of safety in use on environment
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