This study was conducted in order to evaluate the efficacy of the aqueous extracts
of three plants (Melia azedarach L., Smilax asepra L. and Styrax officinalis L.),
three pesticides (acetamiprid, abamectin and pyridaben) and releasing of two
preda
tors (Phytoseiuls persimilis Athias–Henriot and Stethorus gilvifrons Mulsant)
in controlling of Tetranychus urticae Koch populations in tomato greenhouse.
The accuracy of the taxon T. cinnabarinus (Boisduval 1867) as a distinct species, or
as a synonym of Tetranychus urticae Koch 1836, is still standing as a controversial issue of
taxonomy and as a point of discussion. T. cinnabarinus and T. urticae
have been regarded
in the first stage of this study as one species, and it was characterized depending on the
distinctive characteristics of both genders. In the second stage, the two species were
distinguished according to many morphological characters that have been recommended by
authors cited T.cinnabarinus as a valid species. The efficiency of some measures adopted
to distinguish both T. cinnabarinus and T. urticae were also tested. Measurements didn't
match local samples that showed obvious differences, T. cinnabarinus & T. urticae are not
likely to be considered as two different species according to recent researches. Both T.
cinnabarinus and T. urticae were detected on various wild and cultivated host plants. One
hundred samples of plants presented symptoms of tetranychid attacks were collected from
different localities in Lattakia province. Both T. urticae and T. cinnabarinus were found on
29, 9 samples, respectively.
In this experiment, liquid of soap at three dosages (3, 5 and 7 ml/L) and
Abamectin (12.5 ml/100L) has been used with releas of the mite predator,
Phytoseiulus persimilis for controlling the two-spotted spider mite, Tetranychus
urticae on bean pla
nts under laboratory conditions. Contact toxicity of soap
liquid and Abamectin were evaluated and classified according to IOBC.
Efficacy of soap liquid at 3 and 5 ml/L was not sufficient to repress spider mite
populations while the using of soap liquid at three concentration with
predatory mite showed supporter effect and provide satisfactory control
whereas soap liquid determined to be slightly harmful- moderately to P.
persimilis. Abamectin with predatory mite or if used only gave sufficient control
to spider mite population but without supporter effect between Abamectin and
predatory mite whereas Abamectin determined to be harmful to P. persimilis.
However, using soap at suitable dosage, with or without predatory mite, gave
encouraging results for controlling spider mites. Generally, using of soap
showed adaptation with predatory mite and proved supporter effect for
controlling the spider mites. In despite of, soap showed no phytotoxicity to host
plants but needs to be tested in greenhouse and field conditions before
application.
