Allelopathic effects of some Lamiaceae on seed germination and seedling growth of dodder (Cuscuta campestris Yunck.)

Dodder (Cuscuta campestris Yunck.) is one of the parasitic weeds that cause yield losses of many crops and orchards. Control of this weed is very difficult. This experiment was carried out to assay the effects of different concentrations [0 (distilled water as a control), 1.25%, 2.5%, and 5% (gram powder of plant per 100 ml of distilled water)] of lavender (Lavandula vera DC.), rosemary (Rosmarinus officinalis L.), garden sage (Salvia officinalis L.), thyme (Thymus vulgaris L.), and common balm (Melisa officinalis L.) on dodder seed germination and seedling growth. Results showed that all of these medicinal plants had significantly effect on dodder seed germination and seedling growth. So that the highest concentration of lavender, thyme, gardensage, common balm, and rosemary, respectively; dodder seed germination was reduced 58.25%, 25.25%, 25%,23.5%, and 11.25%, respectively. Seedling growth of dodder was more sensitive than that of germination againstextract concentration of all medicinal plant. The present study shows that the inhibitory effect of lavender aqueous extract on germination and seedling growth of dodder was more than that of other medicinal plant tested in this experiment. These results showed inhibitory effects of these medicinal plants extract on dodder seed germination and seedling growth.