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The western flower thrips, Frankliniella occidentalis (Pergande) attacks a large number of crop plants. The current insecticides have caused resistance in insects and have caused outbreaks of thrips. In many instances, alternative methods of insect management and natural products, offer adequate pest control and pose fewer hazards. Several species of minute pirate bugs of the genus Orius play a significant role in the biological control of a large number of thrips species, such as F. occidentalis. In this study, the insecticidal activity of four ethanolic plant extracts (Cercis siliquastrum L., Calendula officinalis L., Peganum harmala L., Melia azedarach L.) in integration with Orius horvathi (Reuter) were evaluated for controlling F. occidentalis. The present research aimed to find plant extracts with a good impact on F. occidentalis but which have fewer side effects on O. horvathi. The results showed that P. harmala extract can be considered compatible with the natural enemy for controlling thrips. When the predatory bugs O. horvathi, were released three days after P. harmala extract spraying, the integration was more effective. While the P. harmala plant extract plays an important role in thrips control, it is necessary to consider the specified time interval between the application of the P. harmala plant extract and the release of the O. horvathi predatory bugs. The ethanolic extract of M. azedarach caused a balance between the pest population and the natural enemy. This result is very important in an Integrated Pest Management (IPM) program because this ethanolic extract of M. azedarach had lower side effects on the natural enemy. This means that an integration of plant derived chemicals and the natural enemy, O. horvathi, can effectively control thrips.
Aphids are one of the most important economic pests and vectors of viral diseases in crops. Brevicoryne brassicae L., one of the most serious aphid pests in Brassicaceae, if not controlled, often reaches very high densities. The present study compared the systemic effects of ethanolic, methanolic and aqueous Melia azedarach L., Peganum harmala L., Calendula officinalis L. and Otostegia persica Boissier extracts with two systemic pesticides, acetamiprid and pirimicarb (at the maximum label-recommended rate). Population growth percentages of B. brassicae through leaf spraying under greenhouse conditions were assessed. The chemicals were sprayed on one of the leaves in greenhouse condition. The results indicated that all the plant extracts have systemic effects at different levels. Among different extracts, O. persica ethanolic extract, P. harmala methanolic extract and M. azedarach aqueous extract resulted in a reduction of the B. brassicae population
Background. Herbal medicines are increasingly used for their effects on the immune system. Silymarin, a mixture of flavonolignans from the seed of milk thistle (Silybum marianum), is used in treatment of liver disease, food and drug poising, and foetal diseases such as viral hepatitis, diabetes, and ischemia. Although, immunostimulant effects of the dietary silymarin were studied on different experimental animals, no information is available about the effects of silymarin on immune parameters of fish. The presently reported study was conducted to investigate the immunomodulatory effects of silymarin on some immunological and haematological parameters of rainbow trout. Materials and Methods. Juvenile rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), were maintained in 1000 L fiberglass tanks at 15 ± 2ºC supplied with systems of water recirculation and aeration. Silymarin extract incorporated into diets (0.0, 0.1, 0.4, and 0.8 g of per 1 kg of feed) of fish. The trout were fed silymarin-supplemented diet for 30 days. Haematological parameters, such as red blood cell count (RBC), white blood cell count (WBC), haematocrit (Hct), haemoglobin (Hb), differential leukocyte- and immunological parameters such as peroxidase, lysozyme, and complement activities, total protein, albumin and globulin levels were measured on day 7, 15, and 30 days of silymarin treatment. Results. The results indicated that oral administration of silymarin in fish, after 15 and 30 days of experimental periods, might enhance haematological and immunological parameters including lysozyme and complement activities, total protein and globulin levels, compared to the controls. Conclusion. The results suggest that oral administration of silymarin may be useful to strengthen the immune system in rainbow trout.
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