Insecticidal efficacy of Paya® (an Iranian diatomaceous earth) against adults of the Cigarette beetle, Lasioderma serricorne (Coleoptera: Anobiidae)
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
The insecticidal efficacy of the diatomaceous earth formulation Paya® against the Cigarette beetle adults, Lasioderma serricorne was evaluated on wheat, barley, peeled rice and maize in laboratory tests. Paya® was applied at the rate of 0.125, 0.25, 0.5, 1.0 and 1.5 g/kg of grain. The adults’ mortality was estimated after 24 and 48 hrs, 7 and 14 days of exposure on treated grains. After 14 days, all the exposed adults were removed and progeny production on treated grains was assessed 45 and 90 days later. Then, emerged adults were counted and classified as dead or alive. Insecticidal efficacy of Paya® against the Cigarette beetle was highly affected by grain type, exposure interval and dose rate. In all grains tested, longer exposure intervals increased mortality. After 24 hrs, mortality at all doses was low (< 20%). After 48 hrs, satisfactory increase of mortality was not observed, but at doses of 0.5, 1.0 and 1.5 g/kg on wheat (ca. 25, 30 and 41%, respectively) and maize (ca. 31, 49 and 45%, respectively) it was more obvious. In contrast, mortalities on barley (ca. 10, 20 and 24.5%, respectively) and rice (ca. 18, 16 and 22%, respectively) were lower. Significant increase in mortality was observed after 7 days. On wheat, mortalities at both doses of 1.0 and 1.5 g/kg were 99.3% but at 0.5 g/kg, it was 56%. On barely, rice and maize, highest mortalities were lower comparing to wheat. After 14 days, 100% of adults died in control, which shows that the Cigarette beetle could not feed and survive on these grain kernels. Progeny production on four treated grains was significantly different and decreased due to the increase of dose. Forty-five and ninety days after removing the treated beetles, progeny production on wheat and barley was higher than rice and maize but both in control and five applied doses, 100% of beetles in F1 and F2 generations were died. Generally, considering the appropriate efficacy of Paya® after 7 days and unsuitableness of grain kernels for this pest, applying the diatomaceous earth Paya® at doses of 1.0 and 1.5 g/kg could only cause significant mortality of adults within 7 days. At longer intervals, adults of the Cigarette beetle will die naturally due to the unsuitableness of these kernels.
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