共查询到20条相似文献，搜索用时 15 毫秒
1.
The insecticidal effect of an aerosol formulation that contained a 100: 1 mixture of pyrethrin and methoprene (by volume), was evaluated for control of nymphs of four stored-product psocid species, Liposcelis bostrychophila, L. decolor, L. entomophila and L. paeta. The aerosol was applied at two particle sizes, 2 and 16 μm. The application time of the aerosols was 0 (untreated controls, no aerosol), 5, 10, 20 and 30 min. Nymphs were examined at 5 days post-treatment. The aerosol was effective on all species tested, with mortality of 100% after 5–20 min, depending on the species. There was a strong interaction between the application time and the particle size. In all cases, the application of the aerosol at 16 μm was more effective than 2 μm for all species. Moreover, the application at 16 μm required less time to reach 100% mortality, suggesting that this particle size may provide a more cost-effective application, as it requires less formulation and a considerably shorter application time. Our results provide the first series of data for the application of aerosols at different particle sizes against stored-product psocids and could be used as a guide for improved management of psocids. 相似文献
2.
In the present study, we investigated the insecticidal efficacy of a commercial binary combination of two pyrethroids, cyphenothrin and prallethrin, as structural treatment against adults of Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Tribolium confusum Jacquelin du Val and Prostephanus truncatus (Horn) in laboratory bioassays. In a first series of bioassays, the insecticide was applied at its label dose on concrete and metal surfaces, whereas mortality and knockdown levels were recorded after 1, 3, 7 and 14 d of exposure. In a second series of bioassays, the residual efficacy of the insecticide was evaluated on concrete for a period of four months, stored either in continuous darkness or exposed to light. In these bioassays, mortality and knockdown of the exposed insects was measured after 3, 7 and 14 d of exposure. Finally, in a third series of bioassays, we investigated the immediate and delayed effect of the tested formulation on adults of the four insect species after exposure for 1, 3 and 7 d. Based on our results, the application of the tested insecticide as surface treatment can provide efficient control against adults of all four species tested. The surface type did not significantly affect the insecticidal efficacy of the tested formulation, at least for the surfaces tested. Moreover, exposure to light negatively affected the residual activity of the insecticide, as for all insect species tested, mortality was significantly lower on dishes exposed to light than on the ones stored in the dark for storage intervals equal or longer than two months. Finally, reduced delayed mortality was observed for all exposure intervals, as knocked down individuals remained, in most cases, knocked down even 7 d after their removal from the treated dishes. 相似文献
3.
Laboratory bioassays were carried out to determine the insecticidal efficacy of a Beauveria bassiana formulation (Bb38, Exosect Ltd, UK), which is based on the combined use of the fungus with the electrostatically charged dust Entostat. The efficacy of Bb38 was conducted on concrete surfaces against adults of the lesser grain borer, Rhyzopertha dominica, the rice weevil, Sitophilus oryzae, the confused flour beetle, Tribolium confusum and the rusty grain beetle, Cryptolestes ferrugineus, in two series of bioassays. In the first series, adults of the above species were exposed on concrete surfaces treated with Bb38 and mortality was recorded after 7 and 14 days of exposure (immediate mortality). These tests were carried out in all combinations of two temperatures, i.e. 25 and 30° C and two levels of relative humidity (r.h.), i.e. 55 and 75%. In the second series of bioassays, adults of the above species were exposed to Bb38 for 7 days, and after this interval, the surviving individuals were transferred in untreated concrete, where mortality was recorded again 7 and 14 days later (delayed mortality). From the species tested, R. dominica was by far the most susceptible, given that mortality reached 100% in almost all temperatures and r.h. levels. From the other species, S. oryzae and C. ferrugineus were moderately susceptible, while Bb38 was less effective for T. confusum. In the second series, immediate mortality for R. dominica was much higher than that of the other species. Moreover, delayed mortality of R. dominica reached 100% in contrast with the other species, where delayed mortality was low. Based on the results of the present work, we found that the insecticidal effect of Bb38 is not affected much by temperature and r.h., for the vast majority of the species and conditions tested. Moreover, in some cases, there was some post-exposure delayed activity of the formulation. This is one of the few studies that examine commercial formulations of fungal-based insecticides against stored product insects, which are expected to provide solutions in stored product protection, where traditional insecticides cannot be applied, as in the case of organic products. 相似文献
4.
5.
The efficacy of partial treatment of two commodities (wheat and rice) with thiamethoxam against adults of Rhyzopertha dominica (F.) and Sitophilus oryzae (F.) was tested by mixing different proportions of thiamethoxam-treated and untreated grains. Thiamethoxam was applied to these grains in two different doses 1 and 5 ppm, while the percentage of the treated grain quantity ranged between 0 and 100%. Adult mortality was recorded after time exposure intervals of 7 and 14 d. Irrespectively of the dose, adult mortality was raised with increase in the percentage of treated kernels as well as the exposure time. Applications of thiamethoxam on wheat were more effective than on rice and on R. dominica than on S. oryzae, especially at 1 ppm, for both exposure intervals. The effective “critical” percentage, causing control similar to 100% treatment, of thiamethoxam to grain mass at 5 ppm was 50% for both species. For the examined scenario of partial treatment, thiamethoxam found to be effective against the tested species which makes it a candidate for use in the stored grain protection. 相似文献
6.
The lesser grain borer Rhyzopertha dominica is a serious pest that causes significant economic damages in stored grains. The presence of this pest is mainly controlled using a small number of insecticides increasing risks of compromising the control efficacy due to the selection of resistant populations. Here, the control failure and potential resistance to pyrethroid and organophosphate insecticides frequently used for the control of R. dominica in Colombia were assessed. Concentration–mortality bioassays with synergized and unsynergized insecticides were used to assess potential metabolic-based pyrethroids resistance mechanisms. Based on the field recommended doses, the results revealed that while the pirimiphos-methyl is still efficient against R. dominica, both type I (i.e., bifenthrin) and type II (i.e., deltamethrin) pyrethroids presented control failure and their insecticidal activity was compromised. Although no differences in susceptibilities between the populations were found for the bifenthrin insecticide, the LC50s of Ibagué (1.83 μl/gr of grains) and El Espinal (1.67 μl/gr of grains) populations were higher than the recommended rate. Furthermore, significant differences in susceptibility to deltamethrin resulted in resistance ratios RR50 > 32-fold and RR95 > 188-fold between the least (El Espinal) and the most (Ibagué) susceptible populations. Moreover, when synergized, the toxicity of deltamethrin was enhanced but resistance ratios kept at high levels (RR50 > 11-fold and RR95 > 40-fold) indicating possible existence of simultaneous metabolic and altered action-site mechanisms of resistance to pyrethroids in Colombian populations. Our results highlight the urgent need for nationwide monitoring of insecticides control failure and resistance in stored pests for better management schemes. 相似文献
7.
8.
9.
简要陈述了家具五金的镀金工艺的发展历史以及现状。从镀金制品的工艺类别，加工技术参数、性能和用材等角度与电仿金工艺相比较，给家具企业选择镀金工艺五金件时做一个参考。 相似文献
10.
The intramuscular administration of penethamate hydriodide over 3 consecutive days and the intramammary administration of an ampicillin/cloxacillin combination were compared in lactating cows suffering from infectious clinical mastitis in one quarter, through an open, randomized, controlled multicenter field trial. Clinical examinations were carried out on d 1 (immediately before treatment), 3, 8, 17, and 22. Milk samples were taken from affected quarters for bacteriological analysis on d 1, 17, and 22, and from all quarters for somatic cell count (SCC) determination on d 1, 8, 17, and 22. There was no significant difference in bacteriological and clinical cure rates between the 2 treatment groups. The systemic treatment with penethamate resulted more frequently in a reduction of the milk SCC below the threshold of 250,000 cells/mL. This also occurred in the adjacent quarters not affected by clinical mastitis but with an SCC above 250,000 cells/mL before treatment. These findings suggest that the parenteral treatment with penethamate provides collateral cure on the quarters of the cows affected by subclinical mastitis. The number of quarters per cow affected by clinical or subclinical mastitis should be considered when selecting an antibiotic treatment by the local or systemic route. 相似文献
11.
Mohamed Hamza El-Saeid 《International Journal of Food Properties》2013,16(5):1119-1127
A supercritical fluid chromatography method for the determination of seven pyrethroid insecticides (allethrin, resmethrin, phenothrin, permethrin, tetramethrin, cypermethrin, deltamethrin) and one of their common metabolites, phenoxybenzyl alcohol, in whole and peeled potatoes and mixed vegetables was developed. The efficiencies of the two extraction techniques, supercritical fluid extraction and microwave-assisted extraction, for the extraction of pyrethroids from vegetable samples were also compared. The retention times of various pyrethroids ranged from 8.4 to 22.9 min, while all of the peaks were well-resolved and distinctly identified. The limits of detection of pyrethroid insecticides ranged between 0.31 and 0.54 ppm, whereas the limits of detection of phenoxybenzyl alcohol was 0.62 ppm. The recoveries of pyrethroid insecticides from whole potatoes, peeled potatoes, and mixed vegetables ranged as 93.83–99.8%, 92.3–105.8%, and 93.67–102.7%, respectively, with the use of supercritical fluid extraction. The corresponding recovery ranges while using microwave-assisted extraction were 94.2–102%, 96.6–101.2%, and 96–103.2%. These findings suggested that supercritical fluid chromatography was a sensitive and rapid technique for the analysis of pyrethroids in complex matrices, such as vegetables, fruits, and other agricultural products. 相似文献
12.
Luis J. Bastarrachea Micha PelegLynne A. McLandsborough Julie M. Goddard 《Journal of food engineering》2013
Modification of food contact surfaces to be antimicrobial represents an approach to address the problem of cross-contamination in the food industry. The effect of increasing levels of surface modification on low density polyethylene (LDPE) through application of N-halamines on the inactivation kinetics of Listeria monocytogenes Scott A was evaluated. Increasing levels of modification were applied through layer by layer deposition on LDPE surface (1–5 double layers of polyethyleneimine and poly(acrylic acid)). Surface modification was achieved and confirmed through Fourier Transform Infrared Spectroscopy (FTIR). From 1 to 5 double layers, the N-halamine content ranged from 3.42 ± 1.2 to 27.30 ± 3.5 nmol cm−2. More than four logarithmic cycles (>99.99%) reduction was reached against L. monocytogenes Scott A after different contact times depending on the level of modification, that varied from 50 to 110 min (from 5 to 2 double layers). Inactivation kinetics followed a sigmoidal behavior. 相似文献
13.
目的 合成拟除虫菊酯类农药人工抗原并对其进行鉴定.方法 采用功夫菊酸和3-间苯氧甲酸2种拟除虫菊酯类农药中间体,与四碳\"间隔臂\"--γ-氨基丁酸反应合成2种半抗原,经质谱鉴定合成成功.以牛血清蛋白为载体,采用活化酯法制备拟除虫菊酯的2种免疫原;以卵清蛋白为载体,采用混合酸酐法制备了3种包被原;经紫外光谱鉴定,粗略计算了... 相似文献
14.
Deterioration and degradation of grains by storage insect pests lead to economic losses of several billion dollars and affect food security. Sitophilus zeamais is responsible for pre- and post-harvest damages to maize. The high toxicity of synthetic insecticides and the development of resistance by insects to the chemicals currently used stimulate the investigation of plant-derived insecticides as new alternatives for pest control. In this study, we report the effects of diets containing Myracrodruon urundeuva leaf extract (10–150 mg/g) and lectin (MuLL; 3–150 mg/g) on the survival, feeding, and nutrition of the storage pest S. zeamais. The digestive enzyme activity in gut extracts from the insects reared on the leaf extract (25 mg/g) or MuLL (15 mg/g) diets was also evaluated. The leaf extract induced mortality (LC50: 72.4 mg/g), while MuLL (30–150 mg/g) exerted strong feeding deterrence. The leaf extract and MuLL promoted the loss of biomass, as reflected in the negative values for relative biomass gain rates and efficiencies in converting ingested food. Protease, trypsin-like, acid phosphatase, and amylase activities in the insects reared on leaf extract or MuLL diets were significantly (P < 0.05) lower than those in the control insects. MuLL ingestion also significantly reduced (P < 0.05) endoglucanase and alkaline phosphatase activities. In conclusion, the leaf extract and MuLL have the potential for S. zeamais control by killing adults and preventing the use of a food source, respectively. The deleterious effects of the extract and lectin on S. zeamais may be linked to enzyme inhibition and consequent suppression of digestive processes. 相似文献
15.
Marcella MastromatteoLucia Lecce Nicoletta De VietroPietro Favia Matteo Alessandro Del Nobile 《Journal of food engineering》2011,104(3):373-379
In this study, polyvinyl alcohol films incorporated with lysozyme, as active compound, and natural fibres were investigated. Various composite systems were developed to control the release of lysozyme from the matrix by using different surface treatments of the natural fibres. Specifically, the plasma enhanced-chemical vapour deposition of acrylic acid and diamond-like coating on spelt bran powders, in a particular home-made rotating plasma reactor, were studied. Moreover, a mathematical model able to describe the release kinetics of the active compound from the polyvinyl alcohol film into water was presented. To validate the model the release kinetic of lysozyme were determined. The model was successfully used to fit the above experimental data, corroborating the validity of the hypothesis made to derive it. Results showed that the incorporation of treated natural fibres to the polymeric matrix allows to obtaining a decrease of the lysozyme diffusion coefficient up to 73.5% compared to active film without fibre. 相似文献
16.
Small and large larvae of the khapra beetle, Trogoderma granarium Everts were exposed for 1, 3, and 7 d on concrete that was treated with chlorfenapyr at 0.055 mg active ingredient (a.i.)/cm2 and 0.11 mg (a.i.)/cm2, deltamethrin at 0.0025 mg (a.i.)/cm2 and 0.005 mg (a.i.)/cm2, pirimiphos-methyl at 0.025 mg (a.i.)/cm2 and 0.05 mg (a.i.)/cm2, pyriproxyfen at 0.000115 mg (a.i.)/cm2 and 0.00023 mg (a.i.)/cm2, and spinosad at 0.05 mg (a.i.)/cm2 and 0.1 mg (a.i.)/cm2. Then, the survived individuals were transferred on untreated concrete for 7 more days and the delayed mortality of small or large larvae was evaluated. Concerning the immediate mortality of small larvae, chlorfenapyr was the most effective among the insecticides tested causing 70% immediate mortality after 7 d of exposure at the higher dose. The other insecticides provided similar mortality levels with the exception of pyriproxyfen which was not effective, for any of the combinations tested, as mortality did not exceed 4.4%. Delayed mortality for chlorfenapyr was also high reaching 76% at 7 d of exposure at the higher dose. Pirimiphos-methyl and deltamethrin gave similar results, indicating that for these two insecticides there is also a noticeable delayed effect. For pyriproxifen and spinosad, the delayed mortality was low. Large larvae were by far more tolerant than small ones in all dose-insecticide-exposure combinations examined for both immediate and delayed mortality counts. The results of the present study show that none of the insecticides were able to totally control T. granarium larvae, illustrating the difficulties in controlling this species, with dose rates that are usually effective for other major stored product beetle species. 相似文献
17.
This study aimed to evaluate insecticidal activity of three diatomaceous earths DEs, two originated from Serbia (DE S-1 and DE S-2) and one commercial formulation (Protect-It, Hedley Technologies Ltd. Canada) applied at rates of 0.5, 1.0 and 1.5 g/kg (500, 1000 and 1500 ppm) on Rhyzopertha dominica in wheat, barley, rye, oats and triticale grains and their effects on mass of kernels and several properties: adherence, hectolitre mass, moisture, protein and ash contents. Mortality of R. dominica adults increased with exposure duration and DEs rates. In all tested grains after the longest exposure period (21 days), 1.0 and 1.5 g/kg rates of Protect-It, and 1.5 g/kg rate of DE S-1 and DE S-2 (in barley) caused 95–100% mortality. Offspring reduction of ≥95% was recorded after the application of 1.0 and 1.5 g/kg of Protect-It and 1.5 g/kg of DE S-1. The lowest weight of damaged grain was found after applying 1.0 and 1.5 g/kg of DEs to all grain types, and the highest in rye and wheat treated with 0.5 g/kg DE S-1 and DE S-2, respectively. The highest DEs adherence of 83–95% was detected in wheat, and 87–92% in oats, and the lowest of 71–77% in rye and 59–73% in triticale. All DEs significantly reduced hectolitre mass of all grains, especially Protect-It, 3.6–8.8%. No negative effects of DEs were detected on moisture contents, and the contents of proteins and ashes in the grains. The changes were due to the activity of R. dominica. 相似文献
18.
Insecticide resistance to three organophosphate (chlorpyrifos-methyl, malathion and pirimiphos-methyl) and three pyrethroid (cypermethrin, deltamethrin and permethrin) insecticides was surveyed in nine field-collected populations of the maize weevil from six Brazilian States and contrasted with a standard susceptible population and a DDT and pyrethroid resistant population. Bioassay tests were carried out in glass vials (20 ml) impregnated with dried insecticide residue and the resistant populations were recognized by using discriminating concentrations established from LC95s estimated for a standard susceptible population. Four field-collected populations had reduced susceptibility to cypermethrin (64-77% mortality) and to chlorpyrifos-methyl (76-77% mortality). All populations were susceptible to malathion and pirimiphos-methyl and only the DDT and pyrethroid resistant check showed resistance to all pyrethroids. Concentration-mortality curves showed non-significant levels of insecticide resistance in the field-collected populations and moderate (10-100-fold) to very high levels (>1000-fold) of resistance to pyrethroids in the DDT and pyrethroid resistant population. Results from insecticide bioassays with synergists (diethyl maleate, piperonyl butoxide, and triphenyl phosphate) suggested a major involvement of esterase as the cypermethrin resistance mechanism, while no clear result was obtained for chlorpyrifos-methyl. Synergism results provide support for target site resistance to pyrethroids in the DDT and pyrethroid resistant population used in this study. 相似文献
19.
目的:研究茯苓三萜对四氯化碳(CCl4)所致小鼠肝损伤的治疗作用。方法:将小鼠随机分为正常组、模型组、联苯双酯组及茯苓三萜高、中、低剂量组共6组。小鼠腹腔注射CCl4橄榄油溶液造模。治疗组以高、中、低剂量(180、90、45mg/(kg.d))茯苓三萜进行灌胃,阳性药物对照组用联苯双酯滴丸(180mg/(kg.d)),皆以1g/100mL羧甲基纤维素钠溶液混悬,0.2mL/10g体质量进行灌胃;正常组与模型组以0.9%生理盐水(0.2mL/10g)体质量灌胃。最后摘眼球取血,收集血清,检测丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)活性;以及小鼠肝组织HE染色后做病理切片观察。结果:与模型组相比茯苓三萜治疗组能够显著降低小鼠血清中AST、ALT活性。病理切片清楚地显示茯苓三萜能够显著减轻小鼠肝损伤的程度。结论:茯苓三萜对CCl4所致的小鼠肝损伤有明显治疗作用。 相似文献
20.
In this study, the properties of molded ramie fibers reinforced with polylactic acid (PLA) biocomposites were investigated. Before preparation of composites, diammonium phosphate (DAP) was applied to the surface of ramie fibers with and without pretreatments to analyze the interfacial adhesion of ramie–PLA composite. Wettability and adhesion behavior of ramie fibers in the PLA resin were characterized by contact angle (CA) measurements. The surface chemical analysis was performed by Fourier transform infrared spectroscopy (FTIR). The thermal properties were recorded using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The wetting analysis results showed that the introduction of DAP treatment to ramie fibers significantly improved the wetting behavior of ramie in the PLA resin. Similarly, the results of TGA indicated that DAP treatment substantially decreased the degradation temperature of the composites. The result of FTIR was also consistent with the results of wettability, TGA, and DSC for the observed changes of peaks in the transmission spectrum. 相似文献