S. Esmaili; M. Rafiei; M. Saidi; S. Beigi; Z. Tahmasebi; M. Mohammadi; M. Kohzadian
Abstract
Tomato early blight disease, caused by Alternaia solani fungus, is one of the most important diseases of tomato in the world, and also in Iran. In order to investigate the antifungal activity of some medicinal plants to control this fungus, separate experiments were conducted in a completely randomized ...
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Tomato early blight disease, caused by Alternaia solani fungus, is one of the most important diseases of tomato in the world, and also in Iran. In order to investigate the antifungal activity of some medicinal plants to control this fungus, separate experiments were conducted in a completely randomized design under in vitro and greenhouse conditions. In the first experiment, the effect of concentrations of 200, 400 and 600 ppm of hydro-alcoholic extract (70% methanol and 30% water) of Thymbra spicata L., Thymus eriocalyx (Ronniger) Jalas, Satureja khuzistanica Jamzad and Oliveria decumbents Vent. with the negative (distilled water) and positive (Daconil, 3 g l-1) controls on the growth of A. solani fungus was studied under in vitro conditions. The results of the first experiment indicated complete inhibiting of fungal colony growth in all treatments. In the second experiment, 72 hours after contamination of tomato plants with A. solani fungus in an isolated greenhouse, contaminated plants were sprayed with the above-mentioned treatments and monitored for the disease symptoms 14 days later. In the third experiment, the protective effect of the above-mentioned treatments was studied. The results of the second and third experiments showed that with an increase in the extract concentration, the inhibitory and protective effects of the treatments increased. Although all treatments reduced the disease severity compared to the control, the concentrations of 600 ppm of T. spicata, 600 ppm of T. eriocalyx and 400 ppm of T. spicata, respectively had the most effective inhibitory and protective effects on the growth of fungus studied. Therefore, the use of the above treatments is recommended as a practical method for biological control of A. solani.
A. Moghadam; M. Saidi; V. Abdossi; M. Mirab-balou; Z. Tahmasebi
Abstract
Plant-derived extracts and essential oils may function as environmentally friendly non-persistent bio-pesticides that are safe for humans as well as other animals. In this study, we investigated the effects of six endemic plant extracts as well as commercial insecticides against Bemisia tabaci and some ...
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Plant-derived extracts and essential oils may function as environmentally friendly non-persistent bio-pesticides that are safe for humans as well as other animals. In this study, we investigated the effects of six endemic plant extracts as well as commercial insecticides against Bemisia tabaci and some physiological responses in cucumber as the host plant at field conditions. The plant extracts and Stamipride as chemical pesticide were sprayed on the plants at 250, 500 and 1000 ppm concentrations. All extracts led to the reduced number of adults as compared with control, among which the greatest impact on the control of this pest was recorded for the extract of Oliveria decombens. Application of all extracts especially at concentrations of 500 and 1000 ppm significantly increased the number of first and second grade fruits. The content of potassium significantly increased and the content of calcium decreased by increasing the concentration of extracts from 250 to 1000 ppm. Results showed that application of extracts and pesticide, especially at high concentrations, imposed negative effects on plant and significantly increased the antioxidant activity in cucumber leaves. In general, all extracts used, especially the extract of Oliveria decombens at a low concentration(250 ppm)was extremely efficient in controlling the adult population of Bemisia tabaci without adverse effects on host plants compared with the commercial insecticide.
