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Effectiveness of several kinds of beer and molluscicides in gastropod control was tested in a 15-week experiment in an allotment garden, using plants of Callistephus chinensis. Among the total of 462 gastropods trapped during the observation period, 98.1% were slugs; the greatest number of gastropods was trapped in July, in the first week of the experiment. The most effective baits were beer Żubr (25.5% of all trapped gastropods), Mesurol SK 04 GB (14.5%) and beer Żywiec Porter (13.2%). The degree of plant damage dependend negatively on the number of trapped gastropods, suggesting a possibility of slug control in allotments by means of various kinds of baits.
Demographic toxicology is recommended for toxicity determination of the long term effects of a pesticide since it gives a more accurate and efficient measure of the effect of a pesticide. Thus, in the current study the sublethal effects of pirimicarb (carbamate insecticide) two concentrations of LC30 and LC10 were used against third instar larvae of Hippodamia variegata (Goeze) in order to determine the effects of the pesticide on demographic parameters of the predator under laboratory conditions. Results showed that pirimicarb did not affect individual life parameters such as development time of larva, pupa, adult longevity, female and male longevity, adult preoviposition period (APOP), and total preoviposition period (TPOP). However, population parameters such as intrinsic rate of increase (r), net reproductive rate (R0), mean generation time (T), and finite rate of increase (λ) was affected by sublethal treatment. For example, intrinsic rate of increase (r) was 0.18 day–1 in the controls but it was 0.13 and 0.14 day–1 in the treated insects with LC10 and LC30 concentrations, respectively. Also, there were significant differences between mean generation time (T) of the treatments and the controls i.e. mean generation time of the controls was 29.03 days while mean generation time in the two treatments of LC10 and LC30 was 33.93 and 31.66 days, respectively. The finite rate of increase was also significantly affected by sublethal effects of the pesticide. The results showed that pirimicarb, even at low concentrations, has potential to adversely affect the predatory ladybird, therefore care should be taken when this insecticide is used in the Integrated Pest Management (IPM) program.
Thrips from the genus Frankliniella (Thysanoptera, Thripidae) are phytophagous on crops and wild plants. Some of them cause slight economic damage, however, others including F. occidentalis and F. intonsa are responsible for considerable losses in crop production. Moreover, they constitute a double threat for host plants by not only feeding on them but also vectoring viruses, some of which are on the quarantined list of the European Plant Protection Organization. The rapid detection and differentiation between more and less harmful Frankliniella species is, therefore, important in order to combat the pests at the time of their appearance. In this study, we have undertaken to develop a method of detecting F. occidentalis, F. intonsa, F. pallida, and F. tenuicornis. The protocol is based on PCR amplification of ITS1 rDNA fragments of these insects using universal primers pair giving products of slightly distinct length for studied insects. Restriction enzymes digestion which is easy to interpret, allows for visible differentiation of all these Frankliniella species. The method was shown to be species-specific and sensitive. Even single specimens in either the larvae or adult stage could be distinguished.
The future of food security in Africa is being severely threatened due to an exponential increase in population, which is almost three times the increase of food production. Maize production is constrained by stem borers which cause significant yield losses. Yield losses can be further compounded by higher temperatures due to climate changes, which are expected to increase the population of maize stem borers. While several methods have been employed in stem borer management, there is still significant damage caused by maize stem borers. This necessitates better control methods including the adoption of recent biotechnological advancement in RNA interference (RNAi) technology. This review highlights evidence of an increase in the stem borer population as well as the foreseen decline in maize production worldwide due to the effects of climatic changes. Furthermore, we have drawn attention to improved methods that have been used to control stem borers in maize production as well as a reluctant acceptance of traditional biotechnology in Africa. Finally, we suggest the application of alternative RNA interference techniques to breed maize for efficient pest control in order to achieve food security, improve nutrition and promote sustainable maize production.
Bioassays were conducted to assess the effects of two silicon dioxide nanoparticles of Aerosil® and Nanosav against adults of Rhyzopertha dominica F. and Tribolium confusum Jacquelin du Val. Silica nanoparticles were applied at the rates of 50, 100, 200 and 300 mg · kg–1 on wheat and peeled barley. The mortality was counted after 1, 2, 3, and 7 days of exposure. Another experiment was carried out to evaluate the effect of food source on the survival of beetles after exposure to silica nanoparticles. Adults were exposed to silica nanoparticles at the rate of 0.2 mg · cm–2 for 1 and 2 days on filter paper inside plastic Petri dishes, respectively. After exposure, the initial mortality was counted and live individuals of both species were held for a week in empty glass vials or vials containing wheat and wheat flour, respectively. Silica nanoparticles have high toxicity on R. dominica and T. confusum adults. Rhyzopertha dominica was more susceptible than T. confusum. However, the mortality of both species increased with increasing concentrations and time exposed to each concentration. At low concentrations, Aerosil® was more effective than Nanosav. Silica nanoparticles were more effective in wheat grains than barley. Results indicated that the initial mortality was so high that the impact of food source on delay mortality was unclear in most cases. Silica nanoparticles were efficient against tested species and can be used effectively in a stored grain integrated pest management program.
The quantity of the crop plant pests have to be under control. A defense against pest organisms with toxic chemicals has been the prevailing pest control strategy for over 50 years. However, plants were found to possess insecticidal properties. Several essential oils act as antifeedants, deterrents and repellents. Essential oils are products of the secondary metabolism in plants. They are mixtures of simple and volatile compounds. One of the example is lavender oil, which repels Ceutorhynchus sp. - the most important pests of Brassica napus var. oleifera plants. The same effect was observed in the case when linalool, linalyl acetate (main components of lavender oil) and lavandulol were applied [Duda, Dubert 2008a, 2008b]. Thymol, the major constituent of thyme oil, is also a deterrent for the lepidopteran pest - Plutella xylostella L. [Akhtar, Isman 2004].
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