This electronic document is a “live” template. The various The saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), is the most important insect pest attacking stored dates in the Unite...This electronic document is a “live” template. The various The saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), is the most important insect pest attacking stored dates in the United Arab Emirates. We sought to determine the time required to cause 100% mortality (lethal time) in O. surinamensis adults incubated at different temperatures, to measure temperature penetration time inside a date mass, and to study date variety preference of O. surinamensis adults. To do this, adults of O. surinamensis were separately incubated at -22℃, 50℃, and 55℃, for 5, 10, 20, 30, 60, 90, and 120 min, per temperature treatment;and we used feeding choice tests on four date varieties (Khelas, Fardh, Lulu, and BuMaán). Results showed that the lethal times of O. surinamensis adults, incubated at -22℃, 50℃, and 55℃, without dates, were 5, 10, and 20 min, respectively;while they were several times higher (30, 90, and 120 min, respectively) in the presence of dates. Results also showed that bigger date masses required either more heating or more freezing time to reach lethal temperatures. We found Khelas to be the least preferred date variety. Future studies should evaluate if heat and chilling injury affect postharvest date quality.展开更多
Laboratory bioassays were conducted to determine the effect of food source on the survival of Tribolium castaneum Herbst, Oryzaephilus surinamensis L. and Rhyzopertha dominica F., after exposure to five diatomaceous e...Laboratory bioassays were conducted to determine the effect of food source on the survival of Tribolium castaneum Herbst, Oryzaephilus surinamensis L. and Rhyzopertha dominica F., after exposure to five diatomaceous earth （DE） formulations： Protect-It, Insecto, Perma-GuardTM, Dryacide and SilicoSec. Adults of these species were exposed to DEs at the rate of 0.5 mg/cm^2 for 1 day on filter paper inside plastic Petri dishes. After exposure, the initial mortality was counted and live individuals of the three species were held for a week in glass vials containing 50 mg wheat flour, rice and whole wheat, respectively. In the second experiment, after 1 day exposure to DEs, beetles were transferred to Petri dishes without food and held for a week to determine if the presence of food source would decrease the mortality of beetles. Experiments were carried out at 27℃ and 55% RH in the dark. The initial mortality in both of the experiments reached 100% for the three species exposed to Protect-It and in the case ofR. dominica and O. surinamensis exposed to Dryacide. In contrast, low level of mortality （〈 10%） was observed for T. castaneum exposed to Perma-GuardTM and Insecto. The mortality after the post-treatment period on food was decreased for the three species exposed to Perma-GuardTM and in the case of T. castaneum and R. dominica exposed to Insecto and SilicoSec. Adults of O. surinamensis were the most susceptible followed by R. dominica and 100% adult mortality was obtained, whereas T. castaneum were the least susceptible beetles to DEs. Protect-It and Dryacide were the most efficient DE formulations and can be used effectively in a stored grain integrated pest management program.展开更多
文摘This electronic document is a “live” template. The various The saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), is the most important insect pest attacking stored dates in the United Arab Emirates. We sought to determine the time required to cause 100% mortality (lethal time) in O. surinamensis adults incubated at different temperatures, to measure temperature penetration time inside a date mass, and to study date variety preference of O. surinamensis adults. To do this, adults of O. surinamensis were separately incubated at -22℃, 50℃, and 55℃, for 5, 10, 20, 30, 60, 90, and 120 min, per temperature treatment;and we used feeding choice tests on four date varieties (Khelas, Fardh, Lulu, and BuMaán). Results showed that the lethal times of O. surinamensis adults, incubated at -22℃, 50℃, and 55℃, without dates, were 5, 10, and 20 min, respectively;while they were several times higher (30, 90, and 120 min, respectively) in the presence of dates. Results also showed that bigger date masses required either more heating or more freezing time to reach lethal temperatures. We found Khelas to be the least preferred date variety. Future studies should evaluate if heat and chilling injury affect postharvest date quality.
文摘Laboratory bioassays were conducted to determine the effect of food source on the survival of Tribolium castaneum Herbst, Oryzaephilus surinamensis L. and Rhyzopertha dominica F., after exposure to five diatomaceous earth （DE） formulations： Protect-It, Insecto, Perma-GuardTM, Dryacide and SilicoSec. Adults of these species were exposed to DEs at the rate of 0.5 mg/cm^2 for 1 day on filter paper inside plastic Petri dishes. After exposure, the initial mortality was counted and live individuals of the three species were held for a week in glass vials containing 50 mg wheat flour, rice and whole wheat, respectively. In the second experiment, after 1 day exposure to DEs, beetles were transferred to Petri dishes without food and held for a week to determine if the presence of food source would decrease the mortality of beetles. Experiments were carried out at 27℃ and 55% RH in the dark. The initial mortality in both of the experiments reached 100% for the three species exposed to Protect-It and in the case ofR. dominica and O. surinamensis exposed to Dryacide. In contrast, low level of mortality （〈 10%） was observed for T. castaneum exposed to Perma-GuardTM and Insecto. The mortality after the post-treatment period on food was decreased for the three species exposed to Perma-GuardTM and in the case of T. castaneum and R. dominica exposed to Insecto and SilicoSec. Adults of O. surinamensis were the most susceptible followed by R. dominica and 100% adult mortality was obtained, whereas T. castaneum were the least susceptible beetles to DEs. Protect-It and Dryacide were the most efficient DE formulations and can be used effectively in a stored grain integrated pest management program.
