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In recent years, different formulations such as nanoemulsions have been widely used for the target delivery, and enhanced biological functions of pesticides combinations. In this study, contact toxicity of Mentha longifolia L. essential oil compared with its nanoemulsion on Ephestia kuehniella Zeller has been investigated. The experiments were conducted and executed at 27 ± 1 °C, and 75 ± 5% relative humidity under dark conditions. Chemical composition of this plant extract was also studied. The main constituents were pulegone (28.84%), 1,8-cineol (19.6%), p-menthan-3-one-cis (8.2%), β-pinene (6.46%) and p-menthan-3-one-trans (5.86%). Results indicated that the mortality rate of 5^th instar larva of E. kuehniella increased with rising concentrations (10000-40000ppm) for oil and (8000-20000 ppm) for nanoemulsion, respectively. The essential oil LC₅₀ was 21352ppm, while this value for nanoemulsion was 14068ppm. According to the results, nanoemulsion was more effective than essential oil. M. longifolia oil had lower durability and the 50% persistent time (PT₅₀) was 2.39 day compared to the nanoemulsion (PT₅₀ = 17.13 day) in the highest concentration of essential oil. The nanoparticle size was 14-36 nanometers (nm) when the transmission electron microscope (TEM) was applied. The surface morphology of nanoemulsion was also studied by TEM. The average size of the particles was estimated 234nm by using laser light scattering apparatus. The overall results of this study show that by using nanoemulsion formulation, the effect of essential oil contact toxicity and its durability increases. Hence, the nanoemulsion slow-release formulation may represent a new category of biopesticides and this should be considered in the integrated pest management program.

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Recently, the methods that improve essential oils (EOs) properties and make them appropriate to be applied as biorational pesticides have been regarded more precisely. The essential oils nanoformulation (EONF) is a promising strategy to develop and facilitate the applicability of the EOs in stored pest management. In this study, the toxicity, antifeedant and physiological effects of Mentha spicata L. and Mentha pulegium L. EOs and their NFs was investigated on the red flour beetle, Tribolium castaneum (Herbst). Characterization of nanocapsules using dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed that the nanocapsules were spherical in shape with the average sizes of 56.91 and 98.99 nm for M. spicata and M. pulegium EONF, respectively. The encapsulation efficiency obtained was 95.47 and 86.03% for M. spicata and M. pulegium EONF, respectively. After 72 h, the LC₅₀ values of the EOs and NF of M. spicata were 18.422 and 9.279 µl/ml and 7.939 and 6.793 µl/ml for M. pulegium, respectively. The results confirmed that the feeding indices of T. castaneum were affected by the EOs and their NFs. In addition, both the EOs and EONF decreased the relative growth rate (RGR) and relative consumption rate (RCR) and had a moderate feeding deterrent activity on the adults of T. castaneum. The EOs and their NFs decreased the general esterase, acetylcholine esterase, α-amylase and general protease and increased the glutathione S-transferases activity of T. castaneum. The overall findings of this research suggest that the NF of the EOs (especially M. pulegium) can be used for an efficient control of T. castaneum. 

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Many of the past experimental research on the design of road pavement layers was confined to the behavior of saturated pavements materials. Among the experimental studies to determine the road layers properties, California bearing ratio (CBR) has been one of the most common and applicable parameter for determination of the resistance of roads subgrade in both design and practical purposes. An extensive amount of research exist in the literature that explains the behavior of California bearing ratio of saturated soils. However, any change in the degree of saturation of subgrade materials and in particular different hydraulic response in wetting and drying paths can affect the CBR value of a pavement material. In compare to the extensive previous studies on the California bearing ratio of soils, this phenomenon is rarely concerned in the previous studies. The goal of this laboratory research is to examine the influence of the initial compaction void ratio, moisture content, degree of saturation, matrix suction and hydraulic hysteresis on the California bearing ratio of a pavement material. To this end, California bearing ratio of sand-kaolin mixture was measured in a range of initial void ratios and initial water contents along drying and wetting portions of the soil-water characteristic curve. The CBR tests along wetting paths was performed on the soil samples that were dynamically compacted and wetted in a range of initial void ratios and initial water contents. The CBR tests for drying paths was also carried out on the soil samples that were compacted identically to the samples used in wetting tests, but they were air dried for seven days before CBR measurements. The air drying process was achieved from the both ends of soil samples as to maintain a homogenous moisture distribution thorough the soil. This was experimentally verified by measuring the moisture contents of top, middle, and bottom portions of the specimens. The CBR values of soil samples were measured within the loading speed of 1.2 mm/min both for wetting and drying paths. According to the laboratory results, it is observed that the CBR value is increased within the increment of initial soil compaction and matrix suction. Based on the results, it is also observed that the value of California bearing ratio of the understudying soil is decreased within increment of the degree of saturation and initial moisture content of the soil. The experimental data also revealed that the California bearing ratio of the pavement material along the drying and wetting paths are not identical, and for a given suction, the CBR values for drying paths possess lower values than the wetting paths. This hysteretic trend for the change of CBR along drying and wetting paths is explained with regard to the hysteretic behavior of the soil-water characteristic curve.

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Nowadays, the increased pest resistance to chemical pesticides and the pesticide residues in food, together with the toxic effects of pesticides on mammals and the environment, necessitate the use of newer and safer alternatives for controlling insect pests. The use of encapsulation technology for pesticides formulations has led to increased efficiency and controlled release of these substances. In this study, four formulations containing Artemisia sieberi Besser essential oil based on biodegradable polymers such as polyethylene glycol, starch, glycerol mono stearate, and maltodextrin were prepared as powder and pellet to control the rice weevil, Sitophilus oryzae. Chemical composition of A. sieberi essential oil was determined and 16 components were identified. Cis-thujone, Santolinyl acetate, Trans-thujone, and Camphor were the major components of the oil. These formulations were different in the amount and type of polymers and surfactants. Also, these formulations were combined with a different rotation speed of the homogenizer. In this study, the fumigant toxicity of these formulations was compared with the A. sieberi oil. The experiments were carried out on the adult stage of the rice weevil at 27±1°C, 70±5% RH and in total darkness condition. The results showed that the LC₅₀ value of the essential oil after 72 hours was 11.33 ppm, while the LC₅₀ of formulations 1 to 4 were 47.61, 57.55, 23.94, and 44.66 ppm, respectively. Therefore, encapsulation of plants essential oils as a safe pesticide with slow release and fumigant toxicity can be used in integrated pest managements.

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The two-spotted spider mite, Tetranychus urticae Koch, is a highly polyphagous pest that is considered a serious pest worldwide. Due to problems associated with chemical pesticides such as resistance to pesticides and environmental contamination, plant oils have been considered for use against mites’ control. However, their low solubility in water and phytotoxicity are the major constraints that limit their application. In this research, a developmental screening process was carried out on some commercial emulsifiers and stabilizers to obtain a safe acaricide from suitable vegetable oils including castor and soybean. Among eight emulsifiers, Nonylphenol Ethoxylate 6M (NPE6) had far more excellent emulsification ability and less phytotoxicity with some level of mite toxicity. Among vegetable oils, castor oil had greater toxicity in comparison with soybean oil. Also, Polyethylene Glycol 400 (PEG 400) had more thermal stability in the formulation. In the last step, the best ratios of NPE6, castor oil, and PEG 400 were evaluated for their toxicity, stability, and phytotoxicity. Finally, the ratios of 1:8:1 or 2:6:2 (NPE6: Castor oil: PEG 400) were found as the best end product that could be potent for use in a large scale rose greenhouse. Also, the efficacy of emulsifier-oil-stabilizer mixtures was investigated against T. urticae by two different methods. The results indicated that the petri dish test method caused overestimating in mortality rates compared to the standing leaf test method. New methods such as polymerization can show a new insight for pest control without chemical pesticides.