| Summary: | Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly,
Bemisia tabaci
(Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of
Ranunculus myosuroudes
Boiss. and Kotschy (Ranunculaceae),
Achillea damascena
L. (Asteraceae), and
Anthemis hebronica
Boiss. and Kotschy (Asteraceae) and leaf extracts of
Verbascum leptostychum
DC. (Scrophulariaceae) and
Heliotropium rotundifolium
Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of
Anthemis scariosa
Boiss. (Asteraceae) and
Calendula palestina
Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species.
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