Synergism and Field Efficacy of Mixed Preparations of Pyraclostrobin and Tebuconazole to Glomerella cingulata

[Objective] This study was conducted to screen high-efficient low-toxicity new compound preparation for control of Glomerella cingulata. [Method] The toxicity of pyraclostrobin, tebuconazole and their mixed preparations to Glomerella cingulata was determined by mycelial growth rate method, and their control effects on Glomerella cingulata were evaluated by field efficacy test. [Result] The mixed preparations of pyraclostrobin and tebuconazole at mass ratios of 5：1, 3：1, 1：1, 1：3 and 1：5 exhibited ECso values to mycelial growth of Glomerella cingulata of 0.612 9, 0.530 1, 0.232 6, 0.232 8 and 0.329 6 iJg/ml, respectively; and the 5 preparations exhibit- ed synergistic coefficients （SRs） to Glomerella cingulata of 1.29, 1.33, 2.29, 1.84 and 1.22, respectively, and among them, the preparation with mass ratio of 1：1 showed the highest synergism. The field efficacy test showed that the field control effects of 1 000 times, 2 000 times and 3 000 times dilutions of 25% pyraclostrobin-tebuconazole suspension, 5 000 times dilution of 430 g/L tebuconazole suspension and 2 000 times dilution of 250 g/L pyraclostrobin EC were 91.54%, 90.80%, 82.88%, 76.43% and 74.10%, respectively. [Conclusions] Therefore, the mixed preparations of pyraclostrobin and tebuconazole showed remarkable synergism on control of Glomerella cingulata, and preparation with the mixing ratio of 1：1 exhibited the most significant synergism on Glomerella cingulata. For soaking treatment to fruit clusters with 1 000-2 000 times dilution of 25% pyraclostrobin .tebuconazole suspension, the field efficacy to Glomerella cingulata was over 90%.

Control of Maize Head Smut with 6% Tebuconazole FS

In order to test the control effect of 6% tebuconazole FS on maize head smut and to select its optimal dose for mixing seed, field tests were performed in 2012 and 2013. The results showed that 6% tebuconazole FS was effective to control maize head smut, and the control effect ranged from 73.4% to 91.1%. In addition, it also improved the maize yield by 36.7%-44.1%, compared with the blank control. The optimal dose of 6% tebuconazole FS for seed dressing was 166.5 g/100 kg to control head smut on maize.

Inhibitory Effects of Phenamacril, Tebuconazole and Their Mixtures on Fusarium graminearum in Wheat

Fusarium head blight caused by Fusarium graminearum is one of the most serious diseases in wheat production worldwide, which seriously affects the yield and quality of wheat. Wheat grains carrying the pathogen are poisonous to human and livestock health. With the long-term use of single chemical pesticide, the drug-resistance of F. graminearum is increasing day by day, and mixed agent is one of the effective strategies to improve the efficacy and delay the resistance. The mycelial growth rate method was used to determine the inhibition rates of phenamacril, tebuconazole and their mixtures(1∶1, 1∶3, 1∶5, 1∶7, 3∶1, 5∶1 and 7∶1). The synergistic coefficient(SR) was calculated by Wadley method, and the combined action types of the two agents were evaluated. The results showed that the ECof tebuconazole was 0.418 28 mg/L, and that of phenamacril was 0.489 8 mg/L; the optimum mixture ratio of phenamacril and tebuconazole was 1 ∶1, with the ECvalue of 0.053 74 and the synergistic coefficient of 4.2696, and the control effect of mixed agent was significantly better than that of single agent. It is feasible to control Fusarium head blight by mixing phenamacril and tebuconazole, providing a theoretical basis for development of new compound agents and effective control of Fusarium head blight.

Inhibition Effect and Synergistic Effect of Prochloraz and Tebuconazole and Their Mixture on Fusarium graminearum

Wheat scab caused by Fusarium graminearum is increasingly severe in the middle and lower reaches of the Yangtze River region. With long-term use of single chemical pesticide,the drug resistance of F. graminearum is growing day by day. In order to reveal the inhibition effect and synergistic effect of prochloraz and tebuconazole and their mixture on F. graminearum,new compound agents for controlling wheat scab were developed. The inhibition effect and synergistic effect of prochloraz and tebuconazole mixed at seven different ratios on F. graminearum were studied. The results showed that the efficiency of the mixture was the best when the proportion of prochloraz and tebuconazole was 1:7; the EC50 was 0.145 36 and the synergistic coefficient was 1.853 9. The results provide a theoretical basis for development of new compound agents and effective control of wheat scab.

Determination of Tebuconazole Residue in Apples and Vegetables by Matrix Solid Phase Dispersion-Gas Chromatography

[ Objective] The study aimed to determine tebuconazole residue in apples and vegetables using matrix solid phase dispersion-gas chro- matography （MSPD-GC）. [ Method] The effects of extraction and determination conditions on the detection of tebuconazole left in apples and veg- etables were analyzed, and the optimum extraction conditions were determined. [ Result] The recovery rate of tebucenazole was the highest when the ratio of a sample to florisil dispersant was 1 ： 4, and the mixture of hexane and acetone （ 1 ： 1 ） with total volume of 8 ml was as the eluant. Under the optimum conditions, the relative standard deviation （RSD） of the method was 4.9% -7.6%, and the detection limit was 0.1 tJg/g, while the re- covery rate of tebuconazole changed from 86.7% to 95. 2% . [ Conclusion] The method was simple, accurate, sensitive and applicable to the de- termination of tebuconazole in aaricultural Droducts.

Application Technology of Tebuconazole WG against Sheath Blight 75% Trifloxystrobin · Rice Blast and Rice

[ Objective] The paper was to confirm the best application period and frequency of 75% trifloxystrobin ·tebuconazole WG against rice blast and rice sheath blight. [ Method] Influences of different dosages and different application periods of 75% trifloxystrobin · tebuconazole WG on control effects against rice blast and rice sheath blight, as well as their effects on rice yields were studied in the paper. [Result] The control effects of three different fungicides application treatments against rice sheath blight were 80.24%, 83.0% and 67.99%, and the control effects against rice blast were 56.4%, 49.11% and 61.1%, respective- ly. Advanced application of fungicide for two times had good prevention effect against rice sheath blight ; properly delayed application of fungicides for two times was conducive to improving the control effect against rice blast, and one time application of sufficient fungicide during middle booting stage had higher control effect than application for two times. Effective panicle number per unit area, total grain number, 1 000-grain weight and moisture content of various fungicide application treat- ments did not have significant difference with those of the treatments without fungicide application, but grain number per panicle in treatments applied with fungicide was higher than the treatment without application. [ Conclusion] 75% Trifloxystrobin ·tebuconazole WG has better control effect on rice blast and sheath blight, which helps to promote the formation of rice grain and increases yield significantly. The fungicide application against rice sheath blight should be appropriately ad- vanced, and application for one time against panicle blast after middle booting stage is helpful to improve the control effect.

Effect of Tebuconazole exposure on oral Atenolol absorption in rats,based on bile acid homeostasis

Objective:This study is aimed to explore the effect of triazole fungicide tebuconazole(TEB)exposure on the oral absorption behavior of atenolol(AT),based on the homeostasis of bile acids(BAs).Methods:TEB was daily gavaged to rats with 3 mg/kg dose for 28 days to establish the TEB-exposure rat model.The amounts of glycocholic acid,glycochenodeoxycholic acid,taurocholic acid and taurine deoxycholic acid in the small intestine contents of normal and TEB-exposure rats were detected by LC-MS/MS.AT(10 mg/kg)were gavaged to the normal and TEB-exposure rats,and then blood were collected from orbital venous plexus at predetermined time-points.The concentration of AT in plasma was detected by LC-MS/MS,and the pharmacokinetic parameters were calculated by the DAS pharmacokinetic software.An intestinal circulation perfusion model was established in normal rats,and perfused with the perfusates containing the model drug of fluorescein and the BAs with the same compositions as the normal/TEB-exposure rats.After perfusion,the absorption and permeability of fluorescein in intestine were detected,as well as the oxidative stress status and ZO-1 expression level in the intestinal tissues.Results:Compared with normal rats,TEB-exposure increased the amounts of glycocholic acid,glycochenodeoxycholic acid,taurocholic acid and taurine deoxycholic acid in intestine significantly(P<0.001).In TEB-exposure rats,the maximum plasma concentration and area under the curve of AT were increased significantly than those of normal rats(P<0.05),and the peak time was significantly delayed(P<0.05).The TEB-induced BAs homeostasis perturbance increased intestinal permeability,and this effect was associated with the elevation of oxidative stress and the down-regulation of intercellular tight junction proteins in intestinal tissues.Conclusion:TEB-exposure can affect the oral absorption behavior of AT,which is probably related with the intestinal BAs homeostasis perturbance,thus it might affect the clinical efficacy and safety of this drug.

Long Term Administration of Lannea acida Rich. (Anacardiaceae) Reverses the Imidacloprid-Induced Fertility Impairments in Adult Male Rat through Androgenic and Antioxidant Properties

Aim: The harmful effects of pesticides have been largely documented in recent times. But effective therapeutic solutions to pesticide related male infertility are yet to be established. This study investigated the curative effects of Lannea acida on imidacloprid (IMI)-induced hypofertility in male Wistar rats. Methods: Rats of 150 – 200 g were administered IMI (22.5 mg/kg) for two weeks and partitioned into control (distilled water, vitamin E, clomiphene citrate) or test (aqueous (340 mg/kg), methanol (170 mg/kg) extract) groups for eight weeks treatment. Animals were sacrificed at the end of the treatment and samples were collected for sperm, antioxidant and hormonal analysis. Fertility tests were performed from treatment day 47 for fertility indices estimation. Results were expressed as mean ± SEM and one way ANOVA was applied using STATISTICA Software. Results: Exposition to IMI resulted in a significant decrease in sperm count, motility, viability and normality, testosterone and LH, coupled to an increase in oxidative stress markers. Moreover, IMI impaired male fertility evidenced by a significant drop in fertility index and litter size. Similar to clomiphene citrate and vitamin E, plant extracts significantly improved the sperm parameters, sexual hormones and decreased the oxidative stress markers. More importantly, the fertility index and litter size were restored, especially with the aqueous extract. Conclusion: Present results indicate that L. acida possesses curative potentials against IMI-induced hypofertility through its androgenic and antioxidant properties. However, the effects the extract on spermatozoa DNA structure and the fertility of offsprings from exposed parents are yet to be studied to conclude on total recovery from IMI toxicity.

Translocation and Distribution of Imidacloprid in Tobacco with Two Application Methods

[Objective] To compare the translocation and distribution of imidacloprid in tobacco with spray and root irrigation application methods. [Methods] Pot experiment in the greenhouse was carried out, and LC-MSMS was used to determine the con- tent of imidacloprid in different parts of tobacco plants （roots, stems, the upper, middle and lower leaves） at different time. [Results] The imidacloprid could be absorbed by root and could be transported to all parts of the tobacco plant after irrigating root, but the original deposition amount was larger and the transport efficiency was lower after spraying. [Conclusion] The translocation and distribution of imidacloprid by spraying was more uniform and the holding efficiency was better, but imidacloprid with root irrigation could act on leaf directly, and had better readily availability.

Effect of Different Concentrations of Pesticide-Imidacloprid on the Main Secondary Metabolites of Fruit and Polysaccharide of Chinese Wolfberry

[Objective] The aim was to seek the appropriate utilization methods for imidacloprid pesticide in the production of Chinese wolfberry,as well as to provide scientific basis for the rational use of imidacloprid pesticide. [Method] The effect of different concentrations and spraying times of 10% WP of imidacloprid on the main secondary metabolites such as carotenoid and flavone,as well as the polysaccharide and total sugar content was studied in field. [Result] The effect of different concentrations of imidacloprid on the secondary metabolites and the content of polysaccharide of Chinese wolfberry was significant. After imidacloprid spraying,the contents of flavone,polysaccharide and total sugar on the 1st,7th and 14th d showed increasing trend,while the content of carotenoid showed decreasing trend. With the dilution times increasing,the content of the flavone,polysaccharide and total sugar showed increasing trend,while the content of carotenoid decreased,in which the highest content of the secondary metabolites and polysaccharide appeared in 1 800 times. [Conclusion] The dilution ratio of 1 800 times should be selected as the appropriate dosage of 10% WP of imidacloprid.

Study on the Degradation Dynamics of Spraying Imidacloprid and Buprofezin before and After Mango Bagging

The four treatments of spraying water the control, spraying before bagging, spraying after bagging, spraying without bagging were conducted by spraying 38% of the mixed suspension agent of imidacloprid and buprofezin, and high performance liquid chromatography （HPLC） method was used to test the imidacloprid and buprofezin residues on mango. The results showed that in 0.05-0.5 mg/kg adding level, the average recovery rate of imidacloprid and buprofezin was 82.6-93.8%, and 101.4-104.2%, respectively, and the relative deviation （RSD） was 1.9-4.5%, 9.3-15.6%, respectively. The minimum detectable amounts of both imidacloprid and buprofezin on mango were 0.01 mg/kg. The half-life periods of imidacloprid under the treatments of spraying before bagging, spraying after bagging and spraying without bagging were 16.74, 6.38, and 8.10 d, respectively, and the half-life periods of buprofezin under the treatments of spraying before bagging and spraying without bagging were 9.72 and 9.23 d, respectively. The residual of buprofezin was low in the treatment of spraying after bagging, and the amount detected in the 3rd day had already below the detectable limit. Bagging treatment reduced the digestion rate of 2 kinds of pesticides in mango, and imidacloprid had strong systemic in mango.

Synthesis and Identification of Artificial Antigen for Imidacloprid

This study reported that a hapten of imidacloprid, 1-[（6-Carboxylethylthio-3- pyridinyl）methyl]-N -nitro-imidazolidinimine was synthesized using technical material of imidacloprid to react with 3-mercaptopropionic acid in hot alkaline solution. The hapten was conjugated to bovine serum albumin （BSA） and ovalbumin （OVA） to form the immuno-antigens and the coating antigen, respectively. The antibody with high titer （2.56 × 10^4） was obtained after immuning rabbits. The results showed that the antibody had a high affinity to imidacloprid tested by enzyme-linked immunosorbent assay （ELISA）, which IC50 and IC20 were 20.7 and 1.1 μg L^-1; and the cross reactibilities to those compounds related with imidacloprid were less than 1.4%.

Adsorption and Leaching Potential of Imidacloprid Pesticide through Alluvial Soil

This study was aimed to assess the adsorption and leaching potential of imidacloprid pesticide in column and field soil. To visibly understand these actions and factors affecting them, the experiments were carried out under laboratory and field conditions. Adsorption study was divided into kinetic and equilibrium sections. The evaluation of kinetic data was done through pseudo first and second order models. It was found that kinetic adsorption of imidacloprid on soil followed pseudo second order with rate constant value of 4.333 mg/g/h. Langmuir and Freundlich isotherms were used to explain equilibrium adsorption, from these isotherms it was evaluated that Freundlich isotherm was obeyed well with adsorption capacity of 2.190 - 4.573 mol/g. Leaching study was performed in laboratory using column made of poly-vinyl chloride having 30 cm length. Known amount of imidacloprid pesticide was applied to column left for adsorption and then eluted with 500 mL water in five equal portions. These water portions and soil of column which was divided into three sections were analyzed by HPLC. The result revealed that the concentration of imidacloprid was decreased from 0.481 ppm in first portion of water to 0.327 ppm in last portion of water while 0.783 ppm in first section of column soil to 0.038 ppm in last section of column soil. In field the leaching power of imidacloprid was observed up to 60 cm depth, its concentration decreased with soil depth. It was 3.311 ppm in first portion of soil and 0.357 ppm in last portion of soil. The leaching potential of imidacloprid pesticide up to 60 cm soil depth was due to less organic matter, sandy texture, alkaline pH, and low cation exchange capacity.

Photochemistry of insecticide imidacloprid: direct and sensitized photolysis in aqueous medium

The direct and sensitized photodegradations of imidacloprid, 1-(6-chloro-3-pyridinylmethyl)-N-nitro-2-imidazolidinimine, were investigated in aqueous solution and with and without various photo-sensitizers. Results of the study revealed that the intensity of lamp-house and irradiation wavelength had significant effects on the photolysis of imidacloprid. Complete degradation of 20 mg/L imidacloprid in aqueous phase was observed in 40 min under ultraviolet(UV) irradiation system, suggesting the ultraviolet ray played significant role in direct photolysis of imidacloprid. The additions of various photo-sensitizers lead to improve the degradation efficiency of imidacloprid under the irradiation of black light fluorescent lamp. TiO 2 was the most efficient in the photo-catalytic degradation of imidacloprid among other photo-sensitizers in used this study. However, addition of acetone inhibited the photolysis of imidacloprid under the irradiation of UV, indicating the occurrence of competition between acetone and imidacloprid for photos. Mineralization of the imidacloprid was examined to clarify the final photochemical degradation products of the insecticide which were CO 2, Cl- and NO- 3. Complete photo-oxidation of nitrogen to NO- 3 occurred very slowly via the intermediate formation of NH+ 4 and NO- 2.

Application of imidacloprid controlled-release granules to enhance the utilization rate and control wheat aphid on winter wheat

During winter wheat production, aphids need to be controlled with pesticides for the entire growth period. Controlled-release technology has been regarded as an alternative method for the improvement of pesticide efficiency. This study investigated two types of imidacloprid controlled-release granule (CR-GR): 2% imidacloprid CR-GR and 0.2% imidacloprid pesticide-fertilizer controlled-release granule (PF-CR-GR) when wheat was sown in winter. The release performance, utilization rate, terminal residues in edible parts, control effect on aphids, and achieved winter wheat yield were evaluated for both laboratory experiments and field application. Imidacloprid PF-CR-GR released more quickly in aqueous medium than CR-GR because of its good water solubility. After CR-GR treatments, the concentrations in wheat roots and soil were similar throughout the entire sampling period, and the concentrations in shoots were about 10–20% of those in roots. Imidacloprid was better absorbed when CR-GR was used as root treatment, compared with foliar treatment. Field application showed that imidacloprid CR-GR and PF-CR-GR controlled aphids throughout the entire growth period of winter wheat and improved the wheat yield. These findings identified application of imidacloprid CR-GR and PF-CR-GR on winter wheat as an effective way to enhance the pesticide utilization rate and ensure adequate yield. This paper provides a theoretical basis for the scientific use of pesticides and guides scientific pesticide application.

Effects of imidacloprid and thiamethoxam as seed treatments on the early seedling characteristics and aphid-resistance of oilseed rape

Seed treatments with the neonicotinoid insecticides imidacloprid and thiamethoxam were evaluated to determine whether the chemicals at effective concentrations for aphid control would influence the germination and early growth of oilseed rape,Brassica napus.Treatment with imidacloprid or thiamethoxam did not affect the cumulative germination rate,but significantly inhibited establishment potential by suppressing root system development in the cotyledon stage.However,these alterations in seedling development in the thiamethoxam-treated seeds appeared not to be detrimental as leaves developed;in contrast,for the seedlings with imidacloprid as seed treatment agent,a significantly decreased shoot/root ratio was still evident at the late two-leaf stage.After two leaves developed,chlorophyll content per leaf in the thiamethoxam treatment was significantly higher than that of the control,while chlorophyll content per leaf in the imidacloprid treatment remained close to that in the control.Most other parameters,i.e.,height,leaf area,weight of stem,leaf or root,and other growth indexes,between the treatments and the control showed no significant difference.Additionally,it was found that storage time of the treated seeds had a significant effect on cumulative germination rate.Treatment 30 d before planting significantly reduced germination relative to that of the control.All of the plants treated with neonicotinoids were shown to have significant anti-aphid characteristics that persisted until the end of the trial.

Imidacloprid in processed tea and tea liquor

Imidacloprid is a newly introduced broad-spectrum chloronicotinyl insecticide and will find its way in agricultural production, particularly in Asia. However, information on the fate of imidacloprid in crop plants is lacking. The degradation of imidaclopnd in processed CTC tea and tea liquor was investigated in the present study in which imidacloprid was applied at recommended application rate （30.0 g a.i./ha） and twice the recommended application rate （60.0 g a.i./ha） for three consecutive seasons. Imidacloprid was rapidly dissipated in processed tea following first order reaction kinetics at all application rates and had half-lives of 0.9 1-1.16 d with the residue in tea liquor found to be below detectable limit on 3rd day samples. The study revealed that imidacloprid is safe for human consumption and will not pose any residual toxicity problem.

Epidemiology of Okra Yellow Vein Mosaic Virus (OYVMV) and Its Management through Tracer, Mycotal and Imidacloprid

Field trials were conducted to evaluate the epidemiological factors of okra yellow vein mosaic virus (OYVMV). Four varieties of okra were subjected to screening and evaluation of the chemicals. The variety Saloni F1 was highly resistant while Subz Pari was moderately resistant. Diksha was the tolerant variety while Lush Green was moderately susceptible. The chemical Imidacloprid was most effective to control whitefly population and okra yellow vein mosaic virus (OYVMV). Correlation of environmental factors (maximum and minimum temperature, relative humidity and rainfall) with percent plant infection of okra yellow vein mosaic virus (OYVMV) was also determined. There was a significant correlation between environment and disease severity.

Effects of 5% Imidacloprid Oil in Preventing Myzus persicae in Different Test Sites

In the research, 5% imidacloprid oil at different doses were applied to prevent Myzus persicae in order to explore significance analysis in 3, 7, 14, and 20 d, respectively, in three fields, and the results showed that 5% imidacloprid oil per- formed significant for K326, G28 and Yunyan-87, suggesting 5% imidacloprid oil is effective in controlling Myzus persicae.

In vitro acute cytotoxicity of neonicotinoid insecticide imidacloprid to gill cell line of flounder Paralichthy olivaceus

In vitro acute cytotoxicity of neonicotinoid insecticide imidacloprid （IMI） to the gill cell line of flounder （FG） that collected in the gill ofParalichthys olivaceus, was examined by 3 widely used endpoint bioassays： NR （neutral red）, MTT （3-（4,5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazoliurn bromide） and TCP （total cell protein）. The result shows that the IMI increased at concentrations ≥0.5 μg/ml. The ICs0 value of NR, MTT, and TCP was 41.86, 38.46, and 39.08 μg/ml, respectively. The ultrastructural observation revealed that the mitochondria of the cells exposed to 60 μg/ml IMI for 48 h were severely damaged, swollen or disrupted, while their nuclei and rough endoplasmic reticulurn （RER） remained normal. This would suggest that the mitochondria are probably the primary target of IMI.