Abstract

Methanol extracts of nine plant species were evaluated for their ovicidal activity against the two-spotted spider mite Tetranychus urticae Koch in a bioassay under laboratory conditions. These plants and plant parts used in the study wereXanthium strumarium L. (fruits and leaves), Anthemis vulgaris L. (flowers and leaves), Humulus lupulus L. (flower buds), Chenopodium album L. (flowers and leaves), Melia azedarach L. (fruits), Eucalyptus camaldulensis Dehn (flower buds and leaves), Solanum nigrum L. (flowers, leaves and fruits), Styrax officinalis L. (seed coats, seeds) and Lolium perenne L. (flowers and leaves). The greatest mortality was caused by E. camaldulensis leaf extract (63.26%), followed by X. strumarium fruit (59.64%), X. strumarium leaf (57.45%), S. nigrum fruit (51.57%),A. vulgaris flower (46.80%) and S. officinalis seed extract (44.25%). Lolium perenne extract (flowers, leaves) caused the least mortality (24.40%). Azadirachtin at 10 g/l concentration was used as a chemical standard and caused 10.09% mortality. Our results show that some of these plant extracts have a potential for ovicidal activity on two-spotted spider mite eggs and are worth further investigation.

Key words: Tetranychus urticae, Eucalyptus camaldulensis, plant extract, ovicidal activity.