Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 82

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 5 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Sitobion avenae
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 5 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
It was confirmed during laboratory tests that two cultivars of spring triticale (Kargo and Migo) developed the highest level of antibiosis against Sitobion avenae, whereas the lowest one was found for Gabo seedlings. Values of daily fecundity (DF) and intrinsic rate of natural increase (rm) were significantly higher for aphids developed on the susceptible cultivar Gabo. Field experiments have shown that cultivars with lower level of antibiosis (Gabo and Mieszko) evolved a stronger ability to recovery of plant injuries and reduction of yield loss caused by the grain aphid. On the other hand, we have found lack differences in density of S. avenae migrantes on the tested cultivars. Thus, these results demonstrate that plants of spring triticale develop two mechanisms of resistance against aphids: antibiosis and tolerance.
Surface waxes from wax-covered triticale plants (RAH 122) were sprayed on plants of the waxless genotype RAH 366 or the surface waxes were used to make artificial diet preparations. The results were significant increases in the mortality of apterous adults of the grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae) at all concentrations tested in comparison with those aphids which fed on the control plants or aphids which were reared on the diets. In the choice tests, most aphids settled on plants without surface waxes or on diet preparations which did not have surface waxes (the controls). When the concentration of the surface waxes was increased on one of the plants or surface waxes were increased in the diet preparation, the number of wandering aphids increased. Those aphids which did not wander were mainly on the waxless control plants or on the waxless diet preparations. Aphids did settle on those plants or on the diet preparations which had 100 and 1,000 μg · g–1 of surface wax. The aphids rarely settled on the diet preparations containing 10,000 μg ∙ g–1 of surface waxes. From these observations it appears that surface waxes can act as a feeding deterrent. Since aphids on plants with surface waxes, or aphids which settled on diet preparations with surface waxes, started to die earlier than aphids fed only the control plants or the control diet preparations, it is possible that the surface waxes had a toxic effect that led to early mortality. Thus, it can be said that the surface waxes caused feeding deterrence and had a toxic effect on the aphids.
The epicuticular wax is the contact point between plants and the environment and plays a crucial role in mediating biotic and abiotic interactions. The associations between the content of epicuticular waxes, on surface plants of winter triticale with their acceptance by the grain aphid Sitobion avenae and bird cherry -oat aphid Rhopalosiphum padi were studied. In general, waxy genotype DED 1137 of winter triticale was less accepted by the cereal aphids than the wax less one (RAH 366). The waxy genotype decreased density of cereal aphids, prolonged maturity and decreased fecundity. Moreover, the comparison of abundance, development and fecundity of the aphid species on the triticale genotypes proved that tested genotypes differed in susceptibility to Sitobion avenae and Rhopalosiphum padi. The importance of the epicuticular wax compounds in the acceptance of plants by the aphids is discussed. The results indicated that aphids fed on waxy plants showed longer time of the prereproductive period and much lower total fecundity. Furthermore, waxy genotype reduced value of the cumulative aphid index and percentage of infested plants.
Extensive studies have been carried out to identify plant proteins with insecticidal properties towards insects. The paper describes a test for screening toxicity and growth inhibition of five commercially available proteins such as: bromelain, honey bee venom, two lectins-wheat germ agglutinin (WGA), concanavalin A (Con A) and lysozyme in artificial diets on Sitobion avenae /F./. Grain aphid proved to be sensitive to all tested proteins. Among the tested proteins concanavalin A and wheat germ agglutinin had the highest negative influence on feeding, reduced weight and increased mortality of tested aphids independently from the dose. It suggested that this group of the proteins have an insecticidal activity and is a good candidate for control of the insect pests.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 5 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.