Field Efficacy Evaluation of 68% Metalaxyl-M·Mancozeb WDG against Dendrobium officinale Blight

The control effect of 68% Metalaxyl-M·Mancozeb WDG against Dendrobium officinale blight was studied. The results showed that the control effect of 68% Metalaxyl-M·Mancozeb WDG at the dose of 1 133-1 360 mg/kg against D. officinale blight was over 78.4% at 14 d post spraying, which was equivalent to that of control agent 72% Cymoxanil·Mancozeb WP(1 200 mg/kg) and 80% Mancozeb WP(1 143 mg/kg).Therefore, 68% Metalaxyl-M·Mancozeb WDG sprayed at the dose of 1 133-1 360 mg/kg could effectively control the damage of D. officinale blight.

Residue Dynamics of Mancozeb in Capsicum annuum Linn and Soil

[ Objective ] The paper was to study the residue dynamics of mancozeb in Capsicum annuum Linn and soil. [ Method ] Field spraying test and indoor analysis were carried out in three places of Changsha, Guangzhou and Beijing City during 2008 -2009 to study the digestion dynamics and the final residue of man- cozeb in C. annuum and soil, and gas chromatography was used for quantitative analysis. [ Result]The average recovery rates of mancozeb in C. annuum and soil were 86.59%-93.03% and 92.57%-95.14%, respectively. Mancozeb had rapid digestion in C. annuum and soft with the half-life of 2.29 -4.65 and 4.01 - 4.65 d, respectively. When metalaxyl-M,mancozeb water dispersible granule was sprayed in C. annuum according to the recommend dose （ spraying for no more than three times with the spraying interval of 5 d）, the final residue of maneozeb in C. annuum collected in the third day after the last spraying was less than 2 mg/kg.

甲霜灵(Metalaxyl)种衣剂防治辣椒苗期疫病效果的初步研究

用甲霜灵 (Metalaxyl)为杀菌剂研制的 2 %甲霜灵种衣剂 ,用量在 6 %以内对辣椒出苗生长安全 ,防治辣椒苗期疫病效果达到 98% ,持效期约 30d左右 ,持效期比 2 5 %甲霜灵WP增加 15d。经气质联用仪分析测定 ,2 %甲霜灵种衣剂包衣后在辣椒幼苗体内含量高于 2 5 %甲霜灵WP拌种处理。

Combined Toxicity Test of Complex Agents of Metalaxyl and Other Fungicides against Phytophthora parasitica var. nicotianae

[ Objective] To overcome the resistance of Phytophthora parasitica var. nicotianae against metalaxyl and effectively control its damage, new efficient complex agent of metalaxyl was studied and developed. [ Method] The toxieities of nine fungicides against P. parasitica were measured using growth rate method. On this basis, the fungicides with good effects were selected to compound with metalaxyl, and the optimum complex ratio was confirmed. [Result] The toxicity of metalaxyl was the strongest with EC50 of 2. 130 5μg/ml; followed by carbendazim, mancezeb and dimethomorph with EC50 of 2.357 9, 2.639 8 and 2. 778 8 μg/ml. The effect of cyazofamid was the poorest with EC50 of 6. 278 8 μg/ml. The optimum complex ratios of dimethomorph, carbendazim and mancezeb with metalaxyl were 40： 60, 30：70 and 20： 80, and their co-toxicity coefficients were 138.80,124.25 and 115.00, respectively. [ Conclusion] The complex agents had application and promotion value, which could be used to carry out further field trials.

Sensitivities of Phytophthora infestans to Metalaxyl, Cymoxanil, and Dimethomorph

The isolates of Phytophthora infestans on tomato in the Guangxi Zhuang Autonomous Region, China, were determined for the sensitivities to metalaxyl, cymoxanil and dimethomorph to give the basic information for integrating disease management. Sensitivities were tested by measuring the radial growth on agar medium amended with fungicide, compared with the floating-leaf-disk method. 239 isolates were collected from eight tomato growing areas during 2000-2006. The testing results indicated that the frequencies of sensitive, intermediate, and resistant isolates to metalaxyl were 42.26, 35.98, and 23.53%, respectively. Variations in sensitivities amongst isolates from different areas or different years were very high for metalaxyl. All isolates from Tianlin and Wuxuan were sensitive to metalaxyl, but the metalaxyl-resistant isolates predominated in Tianyang, with the frequency of 51.35%. The EC50 values of certain isolates from Tianyang were higher than 500 μg·mL^-1 and their resistance levels were over 100 000 folds. Cymoxanil has been used for nearly 10 years in Guangxi, and dimethomorph has been used for 5-6 years. However, there was no decrease in sensitivity of P. infestans populations and the sensitivities of the pathogen were nearly normally distributed. Hence, their mean ECs0 value [cymoxanil （0.1647 ±0.0255） μg·mL^-1, dimethomorph （0.0970 ± 0.0052） μg·mL^-1 could be used as the baseline sensitivities for monitoring the field resistance development. The comparison with the floating-leaf-disk method indicates that both the techniques provided equivalent results. These studies suggested that metalaxyl can be continuously applied in Tianlin, Wuxuan, and Nanning due to the resistant isolates that have not been found, while for those areas with resistant isolate, the use of metalaxyl should be reduced or alternated, and cymoxanil or dimethomorph was recommended for controlling late blight disease of tomato.

Microbial detoxification of metalaxyl in aquatic system

Four microorganisms, Pseudomonas sp. （ER2）, Aspergillus niger （ER6）, Cladosporium herbarum （ER4） and Penicilluim sp. （ER3）, were isolated from cucumber leaves previously treated with metalaxyl using enrichment technique. These isolates were evaluated for detoxification of metalaxyl at the recommended dose level in aquatic system. The effect of pH and temperature on the growth ability of the tested isolates was also investigated by measuring the intracellular protein and mycelia dry weight for bacterial and fungal isolates, respectively. Moreover, the toxicity of metalaxyl after 28 d of treatment with the tested isolates was evaluated to confirm the complete removal of any toxic materials （metalaxyl and its metabolites）. The results showed that the optimum degree pH for the growth of metalaxyl degrading isolates （bacterial and fungal isolates） was 7. The temperature 30℃ appeared to be the optimum degree for the growth of either fungal or bacterial isolates. The results showed that Pseudomonas sp. （ER2） was the most effective isolate in metalaxyl degradation followed by Aspergillus niger （ER6）, Cladosporium herbarum （ER4） and Penicilluim sp. （ER3）, respectively. There is no toxicity of metalaxyl detected in the supematant after 28 d of treatment with Pseudomonas sp. （ER2）. The results suggest that bioremediation by Pseudomonas sp. （ER2） isolate was considered to be effective method for detoxification of metalaxyl in aqueous media.

Determination of Metalaxyl Residues in Watermelon and Banana by HPLC

A determination method for metalaxyl （MEL） residues in watermelon and banana had been established by automated solid-phase extraction （SPE） cou- pled with high performance liquid hromatography （HPLC）. Samples were extracted by acetonitrile, homogenized, filtrated, extracted by automated solid-phase ex- traction （SPE）, and finally purified by C18 column. The experiment was carried on SunFireTM C18 column with the mobile phase of acetonitrile-water-methanol （25： 40： 35, by vol） at the flow rate of 1.0 mL/min. The detection wavelength and injection volume were set at 220 nm and 10 uL, respectively. The recoveries of three different concentrations （0.02, 0.20, 1.00 mg/kg） for watermelon and banana were 94.3 % - 101.0% and 81.5% - 99.6%, respectively. RSD （ n = 5 ） were 1.30% -5.29% and 2.66% -6.67%, respectively. The lower detection limit for metalaxyl was 0. 006 mg/kg. This method met with the requirements of pesticide residue detection. Key words Metalaxyl; HPLC; Watermelon; Banana

Mancozeb： Its Value to the EU Potato Industry

Mancozeb is a multi-site fungicide used to control late blight （Phytophthora infestans） and early blight （Alternaria solani） in potatoes, and is currently due for re-approval as part of the EU Sustainable Use Directive---Authorisation of Plant Protection Products Regulation （EC） No 1107/2009. In order to understand its value to the EU potato industry, a stakeholder survey was conducted to understand the implications for P. infestans control and the impact on EU potato production if mancozeb was not available. In total, 319 growers and advisers were surveyed in 8 countries： France, Germany, Ireland, Netherlands, Greece, Italy, Spain and the UK, to determine how they use mancozeb, potential alternative control strategies and the implications of withdrawal. This study demonstrates that mancozeb is a widely used and cost-effective multisite active ingredient, which is a highly valued means of control for P. infestans. Based on the survey results, a loss of mancozeb would lead to a reduction in gross margin for potato producers in these countries of 787 million to 507 million depending on the level of P. infestans pressure. The combined impact of high cost of production and increased risks is likely to lead to reductions in the availability of EU potatoes and increased costs to consumers. In addition, an assessment was completed to determine the impact of mancozeb withdrawal on fungicide resistance development to single-site acting fungicides, finding that the loss of a multi-site active ingredient like mancozeb would severely compromise fungicide resistance management.

Effects of Vitamin C and NADH on in Vitro Proliferative Function of Human Lymphocytes Exposed to Pesticides （Mancozeb and Metribuzin）

Antioxidants such as vitamin C and NADH can protect against pesticide adverse effects on immune function. The aim of this work was to study the in vitro effects of vitamin C and NADH on the proliferative responses of human lymphocytes exposed to pesticides （Mancozeb fungicide and Metribuzin herbicide） and on Thl and Th2 cytokine secretion. Their possible protective role on intracellular stress oxidative induced by pesticides was also investigated. Peripheral blood lymphocytes were isolated using differential centrifugation on a density gradient of Histopaque. They were cultured with mitogen concanavalin A （Con A）, Mancozeb and Metribuzin （50 μM） in the presence or the absence of vitamin C （50 μM） or NADH （50 μM）. Proliferation （MTT assay）, IL-2, INFγ and IL-4 （Elisa kits）, oxidative markers （intracellular superoxide anion, hydroperoxides, carbonyl proteins, GSH, catalase and SOD） were determined, The results showed that pesticides were immunosuppressive and decreased cytokine secretion with a shift away from to Thl phenotype. These immunomodulatory properties were accompanied by an increase in lymphocyte intracellular oxidative stress. The presence of vitamin C or NADH, in the medium, exhibited protective effects in human lymphocytes by inhibiting pesticide---induced lymphocyte proliferation suppression, inflammatory status and oxidative stress generation. In conclusion, vitamin C and NADH can result in a safe and effective method to reduce pesticide adverse effects and help to restore immune function.

68.75%噁酮·锰锌水分散粒剂对柑桔黑点病的防治效果

柑桔黑点病(由Diaporthe citri引起)是危害柑桔果实商品性最严重的病害之一,每年需要喷施4~5次杀菌剂进行防治。为明确68.75%噁酮·锰锌水分散粒剂(6.25%噁唑菌酮和62.5%代森锰锌的混剂)对柑桔果实黑点病的防治效果,分别在浙江黄岩和常山进行了田间试验。结果发现,黄岩试验点68.75%噁酮·锰锌水分散粒剂500倍液全程5次用药对黑点病的防治效果为84.79%,常山试验点800倍液全程4次用药对黑点病的防治效果为74.10%,效果不亚于常规推荐的杀菌剂代森锰锌。认为,生产中采用68.75%噁酮·锰锌水分散粒剂500~800倍液在柑桔谢花2/3进行第1次树冠喷雾,此后隔20~25 d喷1次,共喷4~5次,可有效防治柑桔黑点病。

Effect of Mancozeb Inhalation on the Olfactory Mucosa in Rats

Background: Mancozeb, (ethylene-bis-dithiocarbamate), is an important fungicide useful against a wide range of fungus affecting ornamental plants, crops, and fruits. We aimed to evaluate the changes in the olfactory mucosa due to mancozeb toxicity and, if cytokine is active, IL-6 immunoactivity. Material and Method: In experimental group, the mancozeb (500 mg/kg) was administered with inhalation to 10 male Wistar Albino rats for five days a week. The control group (n = 10) received distilled water with spray at the same time period. The experiment was terminated after three weeks. Samples were placed in 10% formaldehyde for fixation and placed in paraffin, sections of 5 μm were prepared from paraffin blocks and stained with Hematoxylin-Eosin. Interleukin-6 (IL-6) primary antibody were used for immunohistochemical analysis. Result: In the mancozeb group, olfactory epithelial cell degeneration and apoptosis, inflammation, dilatation and congestion in the vessels were observed. IL-6 expression was increased in vascular endothelium and inflammatory cells. Conclusions: Mancozeb was thought that the increase in IL-6 expression due to the increase in cell degeneration signal was thought to affect the development of cell apoptosis and angiogenesis, and that the use of mancozeb might adversely affect the olfactory mechanism.

烟草中甲霜灵的手性分离方法差异研究

对比反相液相色谱-串联质谱(RPLC-MS/MS)和超临界流体色谱-串联质谱(SFC-MS/MS)手性分离烟草中甲霜灵的差异。烟草样品经乙腈提取、盐析分层、快速滤过型净化(multi-Plug Filtration Cleanup,m-PFC)柱净化后,分别采用RPLC-MS/MS和SFC-MS/MS进行手性分离。从多个性能参数(分离效率、线性、选择性、回收率、重复性、灵敏度、基质效应等)对两种方法进行了全面比较。采用不同的分离方法,在10~500 ng/mL范围内,甲霜灵的不同异构体均可呈现良好的线性关系(R^(2)≥0.9993)。在各异构体加标浓度为0.1、0.5、2.0 mg/kg水平下,采用不同的分离方法均可获得满意的回收率(88.7%~96.2%)和良好的重复性(RSD<7.0%)。结果表明:RPLC-MS/MS和SFC-MS/MS具有互补性,均适用于手性分离和测定烟草基质中的甲霜灵。

代森锰锌对异色瓢虫雌虫生殖毒性初探

在农林业生产中,化学农药的使用成为了生物防治实施的制约因素之一。为了促进化学防治和生物防治的协调应用,评估农药对天敌昆虫的影响是天敌昆虫推广应用中的重要环节。异色瓢虫Harmonia axyridis是我国农业生产中常用的捕食性天敌之一,为了确保异色瓢虫在应用中的安全性,保障其持续发挥控害作用,本文采用毒蚜饲喂法,以卵巢发育情况为指标,评价了常用杀菌剂代森锰锌对异色瓢虫雌成虫的生殖毒性。试验结果表明,不同发育阶段的异色瓢虫在摄入代森锰锌后均会出现雌成虫卵巢发育受抑制的现象。主要表现为卵巢管长度下降、卵巢发育指数降低、Vg1和Vg2相对表达量降低。并且摄入代森锰锌的时间越长,对卵巢发育的抑制作用也越明显。此外,通过解剖观察未发现代森锰锌对异色瓢虫卵巢具有致畸作用。因此,推测代森锰锌对异色瓢虫具有较弱的生殖抑制作用。本文研究结果将增强代森锰锌与捕食性天敌昆虫应用的兼容性,提高代森锰锌与天敌昆虫的使用效率。

缬菌胺和代森锰锌的残留特征及膳食暴露风险评估

本文建立了缬菌胺、代森锰锌及其代谢物乙撑硫脲(ethylenethiourea,ETU)在葡萄和黄瓜中的痕量分析方法,基于储藏稳定性研究阐明了其田间残留特征,并结合我国膳食结构评估了膳食暴露风险。样本经乙腈提取,衍生化后盐析离心,分散固相萃取(d-SPE)净化,超高效液相色谱质谱联用仪(UPLC-MS/MS)检测。缬菌胺、代森锰锌和ETU在葡萄和黄瓜基质中的平均回收率分别为84%~103%、86%~106%和83%~104%,相对标准偏差分别为1.1%~5.7%、0.8%~11.4%、4.4%~11.5%;-20℃避光条件下能在黄瓜和葡萄基质中分别稳定储藏720 d和758 d。缬菌胺和代森锰锌在黄瓜中的半衰期(1.7~2.4 d和1.4~2.7 d)均比在葡萄(6.5~30.1 d和8.6~12.8 d)中的短,而在葡萄中的最终残留浓度(<0.01~0.69 mg/kg)均比黄瓜(<0.01~0.16 mg/kg)中的高。两种果蔬中代森锰锌对儿童群体和一般人群急性膳食风险(%ARfD)分别为0.70%~3.68%和0.48%~2.53%,远低于100%;而代森锰锌和缬菌胺的联合慢性膳食风险为201.3%~831.7%,其中代森锰锌占比99.9%。可见,缬菌胺不会对我国消费者产生不可接受的膳食风险,但需警惕代森锰锌潜在高暴露风险,持续关注其在食物链中的生物累积风险,同步优化膳食结构,为其科学合理使用和健康风险规避提供理论依据。

同位素稀释-液相色谱-串联质谱法测定4类水产品中甲霜灵的残留量

提出了同位素稀释-液相色谱-串联质谱法测定鱼、虾、蟹、贝4类水产品中甲霜灵残留量的方法。取样品(5±0.05)g,加入10 ng的内标甲霜灵-d 6,静置10 min,用10 mL含1%(体积分数)乙酸的乙腈溶液涡旋混合、离心。取上清液,于45℃氮吹至0.5 mL以下,加入7.5 mL 20%(体积分数,下同)乙腈溶液混匀,用7.5 mL正己烷去脂,Agela Cleanert S C_(18)固相萃取柱富集净化。所得溶液于45℃氮吹至干,用1 mL 20%乙腈溶液复溶,混匀后过0.22μm针式水相尼龙滤膜,滤液收集至进样小瓶中。以SHISEIDO CAPCELL PAK C_(18)色谱柱为固定相,以不同体积比的0.1%(体积分数)甲酸溶液和乙腈的混合液为流动相进行梯度洗脱,内标法定量。结果表明,甲霜灵标准曲线的线性范围为1.0~100.0μg·L^(-1),检出限(3S/N)为0.5μg·kg^(-1)。以不同品种水产品为空白基质,在1.0,2.0,10.0μg·kg^(-1)等3个浓度水平下,甲霜灵的回收率为93.8%~105%,测定值的相对标准偏差(n=6)均小于13%。

液相色谱串联质谱法快速测定水中敌百虫等6种农药

随着《生活饮用水卫生标准》(GB 5749—2022)的实施,越来越多的农药纳入了饮用水水质监测,但与之相配套的检测方法尚不完善。文章建立了快速且同时测定水中敌百虫、甲基硫菌灵、西草净、甲霜灵、稻瘟灵、氟乐灵6种农药的直接进样-液相色谱串联质谱检测方法,样品经聚四氟乙烯滤膜过滤后进入液相色谱串联质谱仪进行检测,检出限为0.02~3.1μg/L。纯水回收率为60.5%~120.3%,精密度为0.5%~6.2%;饮用水回收率为69.3%~129.8%,精密度为0.4%~7.5%;地表水回收率为75.1%~127.2%,精密度为0.5%~5.1%。试验中考察了4种不同滤膜对方法回收率的影响,最终确定选用聚四氟乙烯过滤材料。本方法检测效率高、可靠性好,适用于饮用水及地表水的常规以及应急检测。

解淀粉芽胞杆菌SJ1606产脂肽粗提物协同代森锰锌对2种植物病菌的抑制效果

为探明微生物源脂肽粗提物、代森锰锌及二者的复配剂对黄瓜枯萎病菌和葡萄白腐病菌的抑制效果,采用菌丝生长速率法、Horsfall法和Wadley公式法检测了脂肽粗提物和代森锰锌对2种病菌的抑制率和增效比。脂肽粗提物对黄瓜枯萎病菌的EC_(50)为1.93μL·mL^(-1),对葡萄白腐病菌的EC_(50)为5.54μL·mL^(-1),代森锰锌对黄瓜枯萎病菌的EC_(50)为74.37 mg·L^(-1),对葡萄白腐病菌的EC_(50)为48.45 mg·L^(-1)。Horsfall法得出脂肽与代森锰锌混配体积比为8∶2对黄瓜枯萎病菌具显著的增效活性,体积比为1∶9对葡萄白腐病菌具有显著增效活性。通过Wadley公式法得出混配组合对黄瓜枯萎病菌理论EC_(50)为1298.78 mg·L^(-1),实际EC_(50)达472.48 mg·L^(-1),增效比(SR)为2.75;对葡萄白腐病菌理论EC_(50)值为481.41 mg·L^(-1),实际EC_(50)值187.32 mg·L^(-1),增效比(SR)为2.57。结果为2种不同病害的持续防控、化学药剂的减施增效和抗菌脂肽的合理应用提供支撑。

代森锰锌对杨树烂皮病的防治效果

利用室内控制试验,采用药物混合培养基和浸泡法,研究不同质量浓度代森锰锌胁迫对杨树烂皮病菌--污黑腐皮壳菌生长状况、过氧化氢酶(CAT)活性、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量的影响。结果表明:代森锰锌对污黑腐皮壳菌的生长具有较强抑制作用,随处理时间的延长,CAT和SOD活性呈现出先升高后下降的趋势,其中150 mg·L-1代森锰锌处理的污黑腐皮壳菌CAT和SOD活性上升最为明显,在第2小时和第3小时分别达到88 U·g-1 FW和660 U·g-1 FW;MDA含量呈现出升高的趋势,说明污黑腐皮壳菌的菌丝细胞膜脂化较为严重,细胞壁受到严重破坏而崩解。

0.3%精甲霜灵·噁霉灵SP药肥防治辣椒猝倒病及对生长的影响

0.3%精甲霜灵·噁霉灵可溶粉剂药肥是集杀菌剂与肥料优势于一体的产品,采用滴灌施药的方式,研究其对辣椒苗期猝倒病的防治效果和植株生长影响。结果表明:在90和75 kg/hm^(2)滴灌施用量下,0.3%精甲霜灵·噁霉灵可溶粉剂药肥均对辣椒生长具有明显促进作用,平均株高、平均茎粗、根鲜质量、根干质量和壮苗指数均显著高于空白对照,而且促生作用优于18.7%吡唑醚菌酯·烯酰吗啉WG 1.5 kg/hm^(2)+水溶肥75 kg/hm^(2)(CK3)。该药肥均对苗期猝倒病具有较好的防治效果,在处理两次后,2个施用量下的防治效果分别达到89.15%(75 kg/hm^(2))和89.68%(90 kg/hm^(2));死苗率分别为4.34%(75 kg/hm^(2))和4.23%(90 kg/hm^(2))。75和90 kg/hm^(2)的施用量相比较效果差异不显著,因此0.3%精甲霜灵·噁霉灵可溶粉剂药肥75 kg/hm^(2)的施用量符合生产上推广应用要求。

农作物中代森锰锌使用现状及残留检测方法研究进展

代森锰锌主要用于防治农作物褐斑病、炭疽病、霜霉病等,由于长期大量使用,其残留威胁着人体健康,由此引发的农药残留问题也日益受到关注,因此检测并严格控制农作物中代森锰锌农药残留显得尤为重要。对代森锰锌防治常见农作物病虫害种类、农药残留检测方法进行综述,以期为农作物中农药残留检测提供参考。