جستجوی مقالات مرتبط با کلیدواژه "غلظت کشنده" در نشریات گروه "گیاهپزشکی"

The effect of different concentrations of mallow (Malva sylvestris) and poppies (Papaver rhoeas) leaves and walnut (Juglanse regia) green husks extracts were investigated on hatching and mortality of second-stage juveniles of Meloidogyne javanica under experimental conditions. In J2 mortality test, the extracts were used in 14 levels of mallow (0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.75, 1, 1.25, 1.5 and 2%), 7 levels of poppy (0.5, 1.5, 2, 2.5, 3, 3.5 and 4%) and 8 levels of walnut green husks (1, 2, 3, 3.5, 4, 4.5, 5 and 6%). In three independent tests, controlling effect of 100 milliliters of the obtained lethal concentrations (LC20, LC50 and LC80) of each extracts (0.36, 0.58 and 0.94% for mallow; 2.3, 2.9 and 3.8% forpoppies; 2.68, 4.07 and 5.18% for walnut green husks) on M. javanica were evaluated under the greenhouse condition. According to the results of this study, the nematicidal effect of all tested extracts against M. javanica was proved under laboratory conditions. In greenhouse trials, any increase in the concentration of plant extracts significantly improved the growth indices of tomato plants and also the obtained LC80of mallow, poppy and walnut green husks extracts significantly reduced the number of galls by 59, 71 and 74%, respectively, and the reproduction factor by 56.7, 85 and 87%, respectively, when compared to the control.

The sweet potato whitefly, Bemisia tabaci (Genn.) (Biotype A) (Hem: Aleyrodidae) is a major pest of field crops, vegetables and ornamental plants. In this research, the effect of several extraction methods (percolation, maceration, sonication, water bath and soxhlet) on mortality effect offine leaved fumitory, Fumaria parviflora on adults of Bemisia tabaci with leaf dip test were studied. Methanol 3% were used as negative control treatment respectively and tomato as host plant. The calculated LC50 value for above extraction methods were 54.78, 85.04, 85.18, 139.33 and 344.69 g/l respectively and dosage-response gradient was estimated 1.34 ±0.30, 1.08±0.28, 1.0 ± 0.26, 1.39±0.43 and 0.92±0.20 respectively. The results showed that percolation plant extract of F. parviflora had the highest mortality on adult of B. tabaci. It seems that the percolationmethod is the best method to extract chemical compounds to be used against the cotton whitefly. Using this extactct may be a useful strategy against the pest in Integrated Pest Management.