Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 26

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Tribolium castaneum
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Laboratory experiments were conducted to determine the effect of Silicosec by using contact and oral bioassay methods on survival of 1-7 days old adults of Oryzaeohilus surinamensis (L.) and Tribolium castaneum (Herbst) at 27±2°C and 65±5% RH. For contact method adult of these species were exposed to five doses of Silicosec for 3 days on plastic Petri dishes while in the case of oral bioassay technique the species were exposed to maize treated with five doses of Silicosec in small glass vials for 10 days. After exposure the initial mortality was recorded. For O. surinamensis in oral and contact methods 99% mortality was achieved at 8 333 ppm after 10 days and 165 ppm after 3 days, respectively, for T. castaneum 75% mortality achieved at 25 000 ppm after 10 days and 165 ppm after 3 days in the same order. For the oral method LC50 values for O. surinamensis and T. castaneum were 50 and 133 ppm, respectively after 10 days, while for the contact method these criteria were 8 and 57 ppm, respectively after 3 days. The results revealed that Silicosec with contact method could have more deleterious effect compared to the other method, and O. surinamensis was more susceptible to Silicosec than T. castaneum in either bioassay methods.
The essential oils of Zingiber officinale rhizomes (Zingiberaceae) and Piper cubeba berries (Piperaceae) as well as pure compounds, α-pinene and β-caryophyllene, were evaluated for their contact toxicity, persistence of insecticidal and antifeeding activities against T. castaneum and S. oryzae. β-Caryophyllene showed highest toxicity followed by P. cubeba, Z. officinale and α-pinene against both insects. S. oryzae was more sensitive than T. castaneum to both essential oils and pure compounds. α-pinene had least persistence followed in increasing order by β-caryophyllene while Z. officinale and P. cubeba essential oils showed same trends regarding persistence but more than pure compounds. In antifeedant assay, both essential oils and pure compounds exhibited antifeedant activities against T. castaneum and S. oryzae adults. Feeding deterrency was maximum in both insects by P. cubeba essential oil followed by Z. officinale essential oil, β-caryophyllene and α-pinene.
Two flour types (unpolished flour and polished one) and flour textures (grits and fine) of five cereal grains made up of millet, rice, wheat, sorghum and maize were evaluated under laboratory conditions for their susceptibility and progeny development in Tribolium castaneum in hot dry and cool humid seasons. T. castaneum thrived better during the cool humid season than the hot dry season. Polished flour was less susceptible to infestation and supported lower population of the beetles than unpolished flour. Index of susceptibility was 19.65-20.76% in unpolished flour and 18.89-19.76% in polished flour. The number of progeny that developed were 102.6-135.1 and 98.2-121.4 in unpolished and polished flours, respectively. Similarly, grit flour was significantly less susceptible than fine flour in both seasons. Rice, wheat and sorghum flours were less susceptible and supported significantly lower populations of T. castaneum than millet and maize flours in both seasons. Polished wheat flour supported least progeny number than the flour types of the other cereal grains. Conversely, significantly higher number of progeny developed in polished flour of millet and maize and unpolished flour of wheat. Millet fine flour and maize fine or grit flours were significantly more susceptible to infestation than flours of the other cereal grains.
The combined impact of microwave radiation and cold storage on Tribolium castaneum Herbst and Sitophilus oryzae L. adults either continuously or intermittently was evaluated. The insects were exposed to 2 450 MHz at power level of 100 W for exposure time 10 min, continuously and intermittently. In all experiments, the highest rate of mortality was achieved for exposure time 10 min intermittently and 72 h cold storage duration. Intermittent exposures were generally more effective in killing insects of both species compared with those of continuous irradiation. Combinations of microwave radiation and cold storage were found highly compatible and synergistic. The synergistic interaction indicates that microwave radiation can be used with cold storage for management of T. castaneum and S. oryzae adult developmental stage. This treatment could provide an effective and friendly environmental treatment technique in Integrated Pest Management (IPM) program.
Plant secondary metabolites play an important role in plant-insect interactions and therefore such compounds may have insecticidal activity against insects. The chemical composition of the essential oil from leaves and flowers of Lavandula stoechas grown in Kashan, Iran, was studied by gas chromatography mass spectrometry (GC-MS). 1,8-Cineole (7.02%), γ-Cadinene (5.33%), T-Cadinol (5.07%), p-Mentha-1-en-8-ol (5.02%) and Caryophyllene (5.01%) were found to be the major constituents of the oil. In fumigant toxicity tests with the essential oil against adults of Tribolium castaneum Herbst, Lasioderma serricorne F. and Rhyzopertha dominica F. at 27±1°C and 60±5% RH, it was observed that L. serricorne (LC50 = 3.835 μl/l) were significantly more susceptible than R. dominica (LC50 = 5.66 μl/l) and T. castaneum (LC50 = 39.685 μl/l) 24 h after treatment. In all cases, considerable differences in mortality of insects to essential oil vapor were observed with different concentrations and times. Mortality increased as the doses of essential oils and exposure period increased and after 72 h fumigations, greatest percentages of mortality were obtained. The findings indicate the strong insecticidal activity of L. stoechas oil and it may be used in grain storage against insects L. serricorne, R. dominica and T. castaneum.
Humans and animals come into contact with various compounds in their natural environment. Most of the encountered substances are neutral, yet some may carry adverse health effects. The ingested food may be a source of harmful substances, including benzoquinones which, as shown by research results cited in this paper, demonstrate toxic, carcinogenic and enterotoxic activity. This group of compounds is inclusive of 2-methyl-1,4-benzoquinone (MBQ) and 2-ethyl-1,4-benzoquinone (EBQ), defensive secretions of the confused flour beetle (Tribolium confusum J. du V) and the red flour beetle (Tribolium castaneum Herbst). Benzoquinones have a carcinogenic effect, they are inhibitors of growth of various microorganisms, they produce a self-defense mechanism in threat situations and affect population aggregation. As noted by the referenced authors, the properties of benzoquinones have not been fully researched to this date.
Study on the sterilizing and lethal effects of Cobalt-60 gamma radiation on the larval and adult stages of rust red flour beetle Tribolium castaneum (Herbst.) was done at 0, 10, 30, 50, 70, 100, 150, 300 and 500 gray (Gy). Irradiation severely affected pupal period, pupal formation and survivability of larvae and adults. The developmental period of the pest was found to increase along with the increase in the radiation doses. The irradiation at 70 Gy was found to cause complete sterility in the insect.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 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.