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The toxicity of thiamethoxam and pirimicarb on Diaeretiella rapae (Mc'Intosh) as a parasitoid of Lipaphis erysimi (Kaltenbach), exposed to residues on glass vials, was investigated under laboratory conditions at 23 ± 2 °C, 70 ± 5% RH and 16:8 h (L: D). Moreover, in order to find the negative impacts of both insecticides on the efficiency of D. rapae, the functional response of the exposed parasitoids were assessed. The newly emerged parasitoids were exposed to LC₂₅ of the insecticides and distilled water as control. Host densities of 2, 4, 6, 8, 16, 32 and 64 were placed on canola seedlings in a transparent cylindrical container and were offered to the treated parasitoids. Type of functional response was determined by means of logistic regression method and the parameters, attack rate (a) and handling time (T_h) were calculated by nonlinear regression model using SAS software. The parasitoid exhibited type II functional response in all experiments. Attack rates in control, pirimicarb and thiamethoxam were 0.057 ± 0.01,0.059 ± 0.013 and 0.040 ± 0.01 h^-1, and handling times were 1.097 ± 0.1, 1.86 ± 0.02, 2.81 ± 0.296 h, respectively. Maximum rates of parasitism (T/T_h) were estimated 21.87, 12.9, 8.53 aphids, respectively. These observations suggest that pirimicarb with less harmful effects is the preferred candidate for controlling the mustard aphid.

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The toxicity of garlic is confirmed on some agricultural pests. The aim of this study was to comparatively evaluate the sensitivity of Podisus maculiventris (Say) to garlic extract and two insect pests: Mediterranean flour moth Ephestia kuehniella (Zeller) and Colorado potato beetle Leptinotarsa decemlineata (Say). LC₅₀ was calculated at 8.02% for E. kuehniella. The results showed toxic compounds in garlic extract delayed all developmental stages and reproduction parameters of L. decemlineata. In contrast, there were no considerable negative effects on many of the biological parameters of the predatory insect, P. maculiventris. The results suggest that garlic, as a green pesticide, could be considered an environmentally suitable alternative in pest management programs. 

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The effects of four insecticides, abamectin (1500 and 750mgl^-1), emamectin benzoate (1000 and 500mgl^-1), acetamiprid (500 and 250mgl^-1), and flubendiamide (500 and 250mgl^-1), were studied on different preimaginal stages of T. brassicae and T. evanescens, the egg parasitoids of tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae). Parasitized eggs of the Angoumois grain moth Sitotroga cerealella (Lepidoptera: Gelechiidae) were treated by the dipping method at the larval, prepupal, and pupal stages of the parasitoid. For persistence evaluation, the insecticides were applied at the recommended concentration on tomato plants by a hand sprayer till runoff point. Plants were maintained under a transparent polyethylene rain cover in the field. Leaves of the treated tomato plants were sampled and transferred to the laboratory at time intervals of 3, 5, 16, and 31 days after application. Based on our study, abamectin was the most harmful insecticide for immature stages of both parasitoids T. brassicae and T. evanescence. Treatment by abamectin at the pupal stage had more adverse effects compared to prepupal or larval stages. Acetamiprid with 30.5% and 31.6% mortality in less than five days was classified as the short-lived insecticide for T. brassicae and T. evanescens, respectively. The same result was obtained in flubendiamide treatment which caused 27.2% and 26.1% mortality to the parasitoids, respectively. Abamectin with 16.1% and 13.8% mortality in less than 16 days was slightly persistent. However, emamectin benzoate with 13.3% and 15.5% mortality in less than 30 days was classified as moderately persistent for those two species, respectively. Therefore, flubendiamide and acetamiprid were non-harmful to both T. brassicae and T. evanescence wasps and are good candidates to be incorporated into IPM programs in combination with biological agents for the control of tomato leaf miner T. absoluta. By contrast, emamectin and abamectin should be used with greater care as a part of an IPM procedure.

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The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most damaging tomato pests in the world and in Iran. The toxicity of acetamiprid, eforia (thiamethoxam + lambda-cyhalothrin) and hexaflumuron alone and in mixture with emamectin benzoate was studied against 4^th-instars of Tuta absoluta (Meyrick) at 25 ± 2 °C, 65 ± 5% RH and 16:8 (L:D) h. Moreover, the mixtures of examined insecticides with emamectin benzoate at LC₁₅:LC₁₅ ratio were assessed on the general esterase enzyme activity and total protein content of 4^th-instars. The highest toxicity was found for emamectin benzoate after 72 h (LC₅₀ = 0.48 mg a.i./l), followed by acetamiprid (LC₅₀ = 46.94 mg a.i./l), eforia (LC₅₀ = 156.24 mg a.i/l) and hexaflumuron (LC₅₀ = 670.32 mg a.i/l). Mixing emamectin benzoate with acetamiprid at the ratio of LC₅₀:LC₅₀ and LC₂₅:LC₂₅ resulted in synergistic impacts while mix of two other ratios of the same pesticides represented additive influences. The mixture of emamectin benzoate with either hexaflumuron or eforia at all ratios created antagonistic and additive effects, respectively. Mixing emamectin benzoate with either acetamiprid or eforia increased larval esterase activity, however, there was no significant difference between emamectin benzoate in mixture with hexaflumuron and using it alone. Mixing emamectin benzoate with the examined insecticides considerably decreased the larval total protein content. Based on the findings of this work, the mixtures of eforia and acetamiprid with emamectin benzoate represented greater negative effects against 4^th-instars compared to emamectin benzoate alone and the control.
 

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For more than a century, chemical insecticides have been the most primary tool used by growers to control the cotton aphid, Aphis gossypii, as an important polyphagous pest worldwide. The application of insecticide mixtures through different modes of action is currently favored for resistance management of this pest. In this study, the synergistic interactions between amitraz with each of the two commonly used insecticides, i.e. imidacloprid and malathion, were studied using A. gossypii as target pest. The effects of amitraz combination on the activity of three detoxifying enzymes of cotton aphids were then evaluated using physiological assays. The synergistic effects of amitraz on imidacloprid were observed at all Lethal Concentrations (LC₁₀-LC₉₀), while, for malathion it was observed at concentrations higher than LC₃₀. The highest synergist ratio in the mixture of amitraz with malathion (LC₉₀) and imidacloprid (LC₁₀) was 1.5 and 3.09, respectively. The inhibition of Glutathione S-Transferase (GST) activity seems to be the main reason for amitraz to impose its synergistic effects.

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Water hardness can negatively affect the efficiency of pesticides. This study aimed to determine the effect of water hardness and adjuvants added to spray solution on the efficiency of insecticides. Three insecticides, namely, malathion, acetamiprid, and spiromesifen, were mixed in well water samples at 1,869, 645, and 265 mg L^-1 hardness, standard, and deionized water, and applied against the second instar nymph of Bemisia tabaci using leaf dip method. In another experiment, Zero-7 at 150 ppm and Arkan at 180 ppm as additives were added to water with 1869 and 645 mg L^-1 hardness, separately. LC₅₀ values showed that the toxicity of malathion, acetamiprid, and spiromesifen was 40, 157, and 84 times less in hard water (1,869 mg L^-1 hardness) than deionized water. The efficacy of malathion, acetamiprid, and spiromesifen was 13, 65, and 39 times less when they were diluted in water with 645 mg L^-1 hardness than deionized water. Malathion provided 37.28 and 18.59% greater toxicity when applied in hard water containing Zero-7 and Arkan than water without the adjuvants. The efficacy of acetamiprid was, respectively, 16.93 and 18.68% greater when it was applied in hard water containing Zero-7 and Arkan compared to water without the additives. Zero-7 and Arkan in hard water enhanced the efficacy of spiromesifen by 10.26 and 13.68% compared to water without adjuvants. Generally, the toxicity of the insecticides on B. tabaci was considerably reduced at the highest levels of water hardness. In contrast, adjuvants overcame the antagonistic effects of cations in hard water.