Evaluation of Agricultural Contamination Level by Heavy Metals and Pesticides in Sediments of Rivers and Water Bodies for Shrimp Fishing in the Lower Ouémé: Case of the Aguigadji, Ahlan and Sele Stations in Benin

This study assessed sediment contamination by heavy metals and pesticide active ingredients linked to chemical inputs used in agricultural activities in the lower Ouémé. Pesticide residues from the organochlorine, pyrethroid and organophosphorus families were investigated by gas chromatography, and heavy metals (Cd, Pb, As, Ni, Zn, Fe, Mg, Cr and Hg) by atomic absorption spectrophotometry. The metallic pollution indices, the contamination factor (CF) and the ecological risk index were calculated. The results revealed 8 active ingredients in the rainy season and 9 in the dry season. Glyphosate was the active ingredient with the highest concentration at all stations, 9.65 ± 0.84 mg/kg recorded in the dry season at the Aguigadji station. All glyphosate values were above the EQS. DDT, Atrazine and Endosulfan also showed high concentrations in the dry and rainy seasons. Emamectin, Abamectin and Lambda Cyhalothrin also showed high concentrations in the dry season at Aguigadji, Ahlan and Sele. Only glyphosate was recorded at the control station (Toho), but in very low concentrations. Lead showed the highest concentrations at all the stations, 265.96 ± 21.02 mg/Kg in the rainy season and 255.38 ± 79.09 mg/Kg in the dry season, all detected at the Aguigadji station and above the EQS. Zn, Ni, Fe, Cu and Cr were all representative in both the dry and rainy seasons at the contaminated stations. Manganese showed high concentrations in the rainy season. Pb showed very high contamination (FC ≥ 6) at the Aguigadji and Ahlan stations and significant contamination (3 ≤ FC 6) at the Sele station in both the rainy and dry seasons. Ni, Hg and Cd, showed either moderate or significant contamination at the contaminated stations. The risk values showed a considerable ecological Ri (190 ≤ Ri < 380) in the rainy season and a moderate ecological Ri (95 ≤ Ri < 190) in the dry season at these contaminated stations.

Resistance Monitoring of Field Populations of Panonychus citri to Three Pesticides

[Objectives]The paper was to investigate the development of Panonychus citri resistance to commonly used pesticides in major citrus producing areas in China,and to screen out new green and efficient agents for its control and prevention.[Methods]The resistance changes of field populations of P.citri to abamectin,pyridaben,and bifenazate in 12 locations across five provinces in China were compared using the leaf disc impregnation method.[Results]P.citri in the tested areas exhibited the most severe resistance to abamectin,with approximately 91.7%of the field populations showing high levels of resistance to abamectin(112.1-560.5 times);50%of P.citri populations exhibited high levels of resistance to pyridaben(123.0-202.7 times),while the remaining populations showed intermediate levels of resistance(25.6-80.3 times);except for the Zhejiang Xiangshan 2019 and Jiangxi Yudu 2019 populations,which exhibited a medium level of resistance to bifenazate,the remaining 10 monitored populations demonstrated a high level of resistance to bifenazate(140.4-686.1 times).[Conclusions]It is advisable to discontinue the use of abamectin and bifenazate due to significant resistance observed in populations of P.citri monitored in 12 locations across 5 provinces.It is recommended to reduce the frequency of pyridaben use and alternate with other acaricides that have different mechanisms of action due to the varying degrees of resistance developed.

Sensitivity of Commercial Enzyme Inhibition Colorimetric Pesticide Residue Rapid Test Kit to a Variety of Pesticides

[Objectives]To fully understand the quality of commercial enzyme inhibition-colorimetric pesticide residue rapid detection kits,so that they can play a greater role in the detection and supervision of agricultural products.[Methods]The sensitivity of 28 kinds of pesticides was determined by using the commercially available enzyme inhibition colorimetric rapid detection kit with Hendu brand.[Results]There was a significant difference in the sensitivity of the kit to each pesticide,and the kit was more sensitive to dichlorvos among the 28 pesticides tested.The sensitivity to methyl isosalifos,dimethoate,isocarbophos,fenthion and phorate was poor,and the sensitivity to quinalphos was different between 3.0 and 2.5 mL.[Conclusions]The large difference of the sensitivity of the enzyme inhibition-colorimetric rapid detection kit for pesticide residues to different kits is a reason for the false positive and false negative test results of the kit,which needs to be considered by relevant personnel.

Agricultural Contamination of the Surface Waters of the Upper Ouémé in Benin: The Case of Heavy Metals and Pesticides

Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10-4 mg/L;2.2 × 10-1 mg/L;1.2 × 10-4 mg/L;2 × 10-4 mg/L), Cadmium (4.4 × 10-5 mg/L;1.1 × 10-2 mg/L;10-4 mg/L;4 × 10-4 mg/L). Then Copper (7 × 10-4 mg/L;3 × 10-3 mg/L;7 × 10-4 mg/L;1 × 10-4 mg/L), Iron (1.51 mg/L;6.4 × 10-1 mg/L;2.0012 mg/L;2.9 × 10-1 mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10-3 mg/L;1.5 × 10-3 mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, gala super and glycel clearly indicates that these surface waters are subject to agricultural contamination.

Degradation of Extraction from Seaweed and Its Complex with Rare Earths for Organophosphorous Pesticides

On the basis of several experiments carried out in China, it was proved that both seaweed liquid fertilizer and rare earth （RE） could promote the growth of crops and increase their yield. The effects of extraction from seaweed and its complex with RE on the degradation of organophosphorous pesticides and the yield of vegetables were investigated. The resuits showed that the extract and its complex with RE could degrade organophosphorous pesticides in neutral solvent. The residues of the pesticides treated by the extract decreased by 96.88 %, 52.30%, 49.52%, and 22.88 %, respectively, for chlorpyrifos, dichlorvos, omethoate, and dimethoate, and those by the complex decreased by 95.99%, 54.23%, 48.79%, and 25.66%, respectively, when compared with the control. The residues of chlorpyrifos and dimethoate in spinach sprayed with the complex were decreased by 90.64% and 76.56%, respectively, compared with those in spinach from control plots when the interval between spraying and sampling was 8 d. The fresh weight of brassica chinensis and cabbage increased by 28.62% and 18.72%, and their dry weight increased by 44.49% and 14.74%, respectively, compared with those of the controls. The chlorpyrifos and dimethoate residues in brasscia chinese were decreased by 36.36% and 50.00%, respectively, and their rate of decrease in cabbage was 40.00% and 75.00%, respectively, on 5th day after spraying with the complex, when compared with those in the vegetable from control. These results suggest that this complex can increase the agricultural productivity and reduce the use of pesticide residues in the production of vegetables.

Regional selection of insecticides and fungal biopesticides to control aphids and thrips and improve the forage quality of alfalfa crops

The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa(aphids and thrips)were compared in three sites across China’s alfalfa belt.In addition,the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.Efficacy varied among the different biological and chemical insecticides.The chemical insecticides were significantly more effective than biopesticides in a short time-frame.The efficacy period of biopesticides was significantly longer than that of chemical insecticides,and the corrected mortality rate of aphids in all regions was above 50%at 14 days after application.The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.Compared with chemical insecticides,the yield of alfalfa hay was higher in the biopesticides treatments.Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China,and for reducing chemical insecticide usage and improving forage quality.

Recognition mechanism and sequence optimization of organophosphorus pesticides aptamers for better monitoring contaminations in food

Aptamers as a kind of biological recognition element have shown great potential in monitoring and the rapid quantification of organophosphorus pesticides(OPPs). However, molecules of OPPs are structurally similar and original aptamers selected by systematic evolution of ligands by exponential enrichment are usually long-chain bases, which hamper the further application under OPPs-aptamer recognition. The aim of the research was to develop a new strategy to design oligonucleotide sequences for binding OPPs by combination of experimental and molecular modeling methods. 3D models of aptamers binding OPPs were constructed, and binding energy and the most probable binding site for the OPPs were then determined by molecular docking, and the binding sites were further confirmed by the results of 2-AP replaced experiments. Based on the docking results, a new aptamer for detection 4 representative OPPs with only 29 bases was designed by reasonable truncation and mutation of the reported aptamer(named S4-29). The interaction between this new aptamer and OPPs were analyzed by molecular docking, microscale thermophoresis, circular dichroism and fluorometric analysis. The results revealed that the new aptamer exhibit more superior recognition performance to OPPs, which can be promote the monitoring ability of OPPs contaminations in food.

Efficacy of High-efficiency Formula Pesticides for Controlling Sesamia inferens Walker and Ceratovacuna lanigera Zehntner

[Objectives]This study was conducted to screen high-efficiency formula pesticides and precise and efficient application techniques for the prevention and control of Sesamia inferens Walker and Ceratovacuna lanigera Zehntner.[Methods]Field efficacy trials were conducted using different combinations of 70%directed enhanced thiamethoxam seed treatment dispersible powder and 46%monosultap·Bacillus thuringiensis wettable powder.[Results]70%directed enhanced thiamethoxam ZF 450 g/hm^(2)+46%monosultap·B.thuringiensis WP 2250 g/hm^(2)had good control effects on both S.inferens and C.lanigera,so it was an ideal high-efficiency formula pesticide for controlling sugarcane S.inferens and C.lanigera.From January to May,combining with new plant or perennial root cultivation management,70%directed enhanced thiamethoxam ZF 450 g/hm^(2)can be evenly spread on sugarcane ditches and sugarcane stumps after being well mixed with fertilizers applied per hectare,and covered with soil in a timely manner,and during the peak incubation period of the first and second generation of S.inferens eggs from March to May,46%monosultap·B.thuringiensis WP 2250 g/hm^(2)was sprayed to the leaf surface in the mixture with water 675 kg with an electric backpack or a motorized sprayer.In such a way,the control efficacy on dead heart seedlings could reach over 89.8%,and that on C.lanigera could reach 100%.Meanwhile,it could effectively and concurrently control thrips,and the increases in yield and sugar content could reach 29310 kg/hm^(2)and 5.9 percentage points,respectively.[Conclusions]The promotion and application of the formula pesticide could achieve precise application and control of sugarcane pests,and improvement of sugarcane quality and planting efficiency,and help promote green prevention and control of sugarcane diseases and pests and the sustained high-quality development of the sugar industry.

Problems in the Use of Pesticides by Farmers and Countermeasures

Pesticide safety is an important guarantee for food security.At present,there are many problems in the process of choosing pesticides by farmers,such as low discernment ability and difficulty in retroactive blame,slow replacement of medical equipment,slow promotion of technology assistance,lack of professional knowledge,difficult to grasp the key points of application,improper use of pesticides,large resistance to reducing quantity and increasing efficiency,etc.In order to use pesticides rationally and realize safe production,countermeasures and suggestions on pesticide application are put forward from the aspects of drug development and application,promotion of biopesticides,change of farmers concept and cultivation of new farmers.

四种助剂对防治褐飞虱的植物源农药1%印楝素水分散粒剂毒力的影响

【目的】本研究旨在探究橙皮精油(orange peel essential oil,OPEO)、γ-氨基丁酸(γ-aminobutyric acid,GABA)、卵磷脂及马来酸二乙酯(diethyl maleate,DEM)4种助剂对植物源农药1%印楝素水分散粒剂(water dispersible granule,WG)毒力的影响,筛选出有增效作用的助剂,将其作为1%印楝素WG防治褐飞虱Nilaparvata lugens的桶混助剂。【方法】利用稻苗浸渍法和连续浸液法评价印楝素及添加助剂OPEO、GABA、卵磷脂或DEM后对褐飞虱3龄若虫的毒力;测定印楝素(20 mg a.i./L)及添加助剂处理后,褐飞虱3龄若虫体内谷胱甘肽S-转移酶(glutathione S-transferase,GST)、羧酸酯酶(carboxylesterase,CarE)及乙酰胆碱酯酶(acetylcholinesterase,AChE)3种酶活性;测定添加助剂后对印楝素药液(40 mg a.i./L)与水稻叶片接触角的影响。【结果】稻苗浸渍法处理后96 h,添加DEM使印楝素对褐飞虱3龄若虫胃毒性毒力显著增强,增效比为1.512;连续浸液法处理后72 h,添加OPEO或DEM使印楝素对褐飞虱3龄若虫内吸性毒力显著增强,其增效比分别为1.486及1.560;添加OPEO或DEM分别使褐飞虱3龄若虫体内GST活性比印楝素单剂处理分别降低69.4%和65.5%;添加DEM使CarE活性比印楝素单剂处理降低88.2%;添加OPEO或DEM后,印楝素药液液滴与水稻正面叶片的初始接触角从110°分别降至64.5°或67.9°。【结论】添加OPEO或DEM能明显提高印楝素对褐飞虱的毒力,提高印楝素药液在水稻叶片上的润湿性。因此,将OPEO或DEM作为1%印楝素WG防治褐飞虱的桶混助剂有一定的应用价值。

复合药剂对沃柑保鲜及农药残留的影响

为了提高沃柑贮藏期的保鲜效果,同时确保安全用药,以沃柑果实为研究材料,用不同复合药剂处理后再薄膜单果包装,测定沃柑果在(6±1)℃冷库中不同贮藏期的失重率、可溶性固形物含量、好果率和药物残留量。结果表明,不同复合药剂处理沃柑的保鲜效果及农药残留存在不同程度差异,其中,经50%抑霉唑乳油250倍液+40%双胍三辛烷基苯磺酸盐可湿性粉剂3000倍液+20%烯肟·戊唑醇2000倍液+2,4-滴钠盐200 mg/L处理后的沃柑果实保鲜效果最好,贮藏60 d时好果率达99.67%,贮藏90 d时好果率仍有98.33%,能有效减缓贮藏后期(60 d以后)可溶性固形物含量的下降,果皮和果肉中双胍辛胺、2,4-滴和抑霉唑的残留量较低,且烯肟菌胺、丙环唑、戊唑醇的残留量远低于我国标准(GB 2763-2021)限定值。

引诱剂与杀虫剂联合使用对茄子黄胸蓟马的防治效果

由于化学杀虫剂的频繁和高剂量使用已渐渐失去对蓟马的防控效果,为进一步探究杀虫剂与引诱剂在控制蓟马方面的联合作用,本文通过设置不同剂量的杀虫剂与蓝板引诱剂进行复合诱杀蓟马,并与单独使用杀虫剂或蓝板对黄胸蓟马的防治效果进行了比较。结果表明,随着处理时间的增加,不同杀虫剂处理对黄胸蓟马的防治效果逐渐升高,总体上,复配药剂的防效要好于单剂药剂。且在药后3 d,30%虫螨腈·唑虫酰胺悬浮剂对黄胸蓟马的防效(84.36%)要显著高于240 g/L虫螨腈悬浮剂(74.32%)、15%唑虫酰胺悬浮剂(76.84%)、3%甲氨基阿维菌素苯甲酸盐微乳剂(71.85%)三个单剂的防效。药后10 d,30%虫螨腈·唑虫酰胺悬浮剂对黄胸蓟马的防效最高可达90.17%。杀虫剂与蓝板引诱剂联合使用对黄胸蓟马的田间防治效果要显著好于仅用杀虫剂的防效,而且在药后3 d、7 d和10 d,复合药剂或单剂对黄胸蓟马的防效均高于90%,最高可达98.54%,说明蓝板引诱剂对黄胸蓟马起到了很好的防治效果。在单独统计蓝板引诱剂的防治效果时发现,对黄胸蓟马防治效果高的药剂,与其联合作用中的蓝板诱集效果比较低;反之,对黄胸蓟马防治效果低的药剂,与其联合作用中的蓝板诱集效果比较高;这也说明蓝板诱集可作为低剂量杀虫剂用于防治蓟马类害虫的有效互补措施。本研究明确了杀虫剂与引诱剂的联合作用效果,以期在提高蓟马防治效果的同时降低杀虫剂浓度或减少其使用剂量,为害虫综合防控措施提供参考。

7种药剂对羊肚菌生长的影响及农药残留研究

测定7种杀虫药剂施用对羊肚菌生长的影响及其农药残留。结果:经7种药剂处理的羊肚菌在平均产量、菌盖直径、菌柄长度、菌柄直径与单个鲜菇重方面与对照(CK)差异不显著;而菌盖长度以5 g/L溴氰菊酯乳油处理的最短,并与22%阿维·螺螨酯悬浮剂、24%螺螨酯悬浮剂、1.8%阿维菌素乳油、5%甲氨基阿维菌素苯甲酸盐水分散粒剂处理具有显著差异,与对照(CK)差异不显著。1.8%阿维菌素乳油、5 g/L溴氰菊酯乳油、8%阿维·哒螨灵乳油处理的羊肚菌未检出农药残留;24%螺螨酯悬浮剂与110 g/L乙螨唑悬浮剂处理的农药残留在GB 23200.121—2021限量范围内;22%阿维·螺螨酯悬浮剂处理的阿维菌素残留量超出标准限量0.5 mg/kg,螺螨酯残留量在限量范围内;5%甲氨基阿维菌素苯甲酸盐处理的水分散粒剂残留量超出标准限量2.7倍。

全自动固相萃取结合气相色谱-串联质谱法快速测定石斛中62种常用农药残留

建立全自动QuEChERS方法结合气相色谱-串联质谱技术检测石斛中62种常用农药残留的分析方法。样品经全自动QuEChERS样品制备系统涡旋、振动和离心处理,HP-5MS色谱柱分离,选择分时间段的多反应监测模式进行数据采集及定性定量分析,内标法定量。62种农药在5~500ng·mL^(-1)范围内线性关系良好,相关系数(r^(2))大于0.99;3个加标水平下(0.01mg·kg^(-1)、0.05mg·kg^(-1)和0.1mg·kg^(-1)),平均回收率为65.6%~109.3%,相对标准偏差(RSD)为2.4%~15.1%;定量限均低至0.01mg·kg^(-1)。该方法简便、快速、灵敏、准确性高,适用于石斛中62种常用农药残留的快速检测。

浙江省西瓜中农药残留风险评估

分析流通于浙江市场及全省各地生产的西瓜农药残留情况,明确其中农药残留种类及其水平,并对其农药残留风险进行评估。结果显示,288份西瓜样品共检出29种农药残留,其中检出率较高的3种农药分别为吡唑醚菌酯、啶虫脒、腐霉利;除草甘膦和噻虫嗪各有1例超标外,其他检出农药均符合我国农药最大残留限量标准要求。单项污染指数和急慢性膳食摄入风险值表明,浙江省西瓜膳食摄入风险均为可接受状态,暂无健康风险。此外,要重点关注他国(地区)严格于我国的农药残留限量,立足本国需要,制定符合我国西瓜生产实际和保护我国消费者健康的农药残留限量标准,积极开展国内外标准转化,主动接轨国际提高我国西瓜产业的竞争力。

农药喷雾系统建模与仿真技术研究综述

农药使用效果与农药喷雾过程密切相关,农药喷雾过程的建模与仿真可弥补因植物生长周期差异、病虫害发生程度不同以及田间作业自然环境不可控等造成的试验研究困难。分析农药施用的抗性、再增猖獗、残留(resistance,resurgence,residue,3R)/效果、效率、生态(efficacy,efficiency,eco-environment,3E)/方法、模型、测试(method,model,measurement,3M),重点综述农药喷雾过程的雾化、输运、沉积等关键环节的模拟仿真研究状况。根据模拟仿真技术发展趋势,提出农药喷雾半实物仿真系统设计的建议,并提出雾化模型及新型喷头雾化机理、群体农药雾滴多相流场模拟、靶标定制与识别模型、综合农药雾滴飘移模型、植物生长模型与农药喷雾系统耦合等建议,以促进原创农药精确喷雾技术研究和高质量植保机械研发。

我国细菌类微生物农药的登记情况与应用策略浅析

细菌农药是最早被商业化开发应用的微生物农药之一,其无论在作物虫害还是病害防治中都有较为广阔的应用前景。通过对中国农药信息网的检索统计,梳理了当前我国细菌类微生物农药登记应用情况。截至2023年11月在我国登记应用的细菌类微生物农药有效成分已达30个,登记产品共计336个(母药40个、制剂296个)。细菌类微生物农药的科学管理与应用对减少化学农药用量,保障我国高品质农产品的安全生产具有十分重要的现实意义。

气相色谱-三重四极杆质谱法测定黄芪中42种农药残留

目的建立气相色谱-三重四极杆质谱法测定黄芪中42种农药的方法。方法黄芪中的多组分农药采用乙腈提取,上清液经N-丙基乙二胺、十八烷基硅烷键合硅胶、硅胶净化,采用程序升温进样口上机测定,基质匹配曲线外标法定量。结果42种农药在0.01~1.00μg/mL范围内线性关系良好,相关系数为0.9954~0.9999,在空白基质中添加低(0.02 mg/kg)、中(0.40 mg/kg)、高(2.00 mg/kg)3个不同浓度的混合标准品各6份,加标回收率为72.5%~109.3%,相对标准偏差为1.25%~6.07%,检出限为0.002~0.010mg/kg,定量限为0.005~0.030 mg/kg。在100批次黄芪样本中检出6种农药,分别是α-硫丹、对硫磷、甲基对硫磷、硫环磷、氯氰菊酯、氰戊菊酯,样品检出率6.0%,样品超标率1.0%,超标农药为氯氰菊酯。结论本方法灵敏度高、准确性好,适用于黄芪中42种农药的同时测定。

2023年中国农药工业运行回顾

2023年,我国农药行业营业收入、利润负增长,30多年来首次出现双下滑,出口贸易量增价跌,农药总产量小幅下降,产品价格大幅下跌。面对如此形势,行业积极应对市场的多重风险与挑战,努力保持稳中求进,以进促稳的局面。预计2024年农药行业整体经济运行情况将企稳回升,有望整体好转。

新疆棉花病虫害防治药剂剂型研发策略

棉花是我国重要的经济作物,也是受病虫害危害最严重的农作物之一。目前化学防治仍是棉田病虫害防治的重要技术。新疆棉区是我国最大的棉花主产区,气候类型属于典型的温带大陆性气候,具有光照充足、夏季高温干旱、多风、昼夜温差大等特殊气候特点,农药药液喷施过程中容易发生蒸发、飘移、降解等损失,严重影响药剂的防治效果。本文综述了温湿度、风、光照等环境因子对药剂防治效果的影响,以及国内外对提升药剂防治效果采取的调控措施,并结合新疆棉田的特殊气候条件提出了剂型研发的新策略。在提升产品理化稳定性的前提下,还需综合考虑有效成分的理化性质、棉花叶片的结构及润湿特性、施药器械等多种因素。结合农药学、植物保护学、界面化学、有机化学等多学科交叉理论知识指导,利用先进的技术和载体材料研发环境响应型、靶向高效的农药剂型,结合配套使用技术及措施,探索农药高效利用及减量调控途径,为实现农药减量增效、引领棉花产业绿色发展提供科技支撑。