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Abstract
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The date palm spider mite (DPSM), Oligonychus afrasiaticus (McGregor), is one of the most important noxious pests in many date palm-plantations of south of Iran. In the current study, acaricidal activity of some plant-based compounds including Dayabon®, Palizin®, Tondexir®, and garlic ethanolic extract on the adult mites was investigated under laboratory conditions (27±1 ˚C, 60±5 % RH and 16:8 L:D) using dipping bioassay method. Based on the initial experiments to cause 20 and 80 percent mortality, five logarithmic concentrations of each compound including 1500, 2280, 3465, 5265, and 8000 ppm for Dayabon, 500, 840, 1420, 2380, and 4000 ppm for Palizin and Tondexir, and 15000, 23000, 35000, 53000, and 80000 ppm for garlic extract, were tested in five replications (each replication consisted of 20 one-day-old DPSM adults established on date fruit in 8 cm diameter plastic Petri dish); distilled water was used as control. After 24 hours, dead mites were counted in each replication and LC50 for compounds were calculated using Probit technique by SPSS software. The highest and lowest percentage mortality of DPSM were achieved 19.2 and 78.1%, 19.7 and 86.2%, 27.3 and 95.4%, and 28.6 and 84.5% for Dayabon, Palizin, Tondexir and garlic extract, respectively. The LC50 was determined 3601.8, 1289.3, 1031.6, and 26955.7 ppm for Dayabon, Palizin, Tondexir and garlic extract, respectively. Based on the results, even though Tondexir had the lowest LC50 value, all compounds could be considered for integrated DPSM management due to their eco-friendly nature. This matter should be taken into consideration that many other aspects of these compounds need to be thoroughly investigated before recommending their use. These aspects may include their effects on non-target creatures, especially DPSM's natural enemies, environmental effects, pre-harvest interval, residues in date palm fruits, and the cost and benefits of their application.
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