Pythium rot of Chinese cabbage (Brassica rapa L. subsp. pekinensis) caused by Pythium aphanidermatum

Severe rot was found at the base of leaves and stems of Chinese cabbage (Brassica rapa L. subsp. pekinensis) in Ibaraki Prefecture every year in early September from 2002 through 2004. The causal fungus was identified as Pythium aphanidermatum (Edson) Fitzpatrick. This is the first report of P. aphanidermatum on Chinese cabbage. A similar disease of Chinese cabbage caused by P. ultimum Trow var. ultimum is known as Pythium rot. We propose adding P. aphanidermatum as a new pathogen of this disease.     

Colonization by two isolates of Plasmodiophora brassicae with differing pathogenicity on a clubroot-resistant cultivar of Chinese cabbage (Brassica rapa L. subsp. pekinensis)

A commercial clubroot-resistant F₁ cultivar of Chinese cabbage (Brassica rapa L. subsp. pekinensis), Kukai 70, is resistant to an isolate of populations of Plasmodiophora brassicae from Hagi (HG) city and is susceptible to another from Yamaguchi (YMG) city. The degree and frequency of primary and secondary cycle colonization by the isolates in the root hairs and root tissues of cv. Kukai 70 were compared. Seedlings of cv. Kukai 70 were grown in soils amended with inoculum of either HG or YMG and harvested 10 days after inoculation to observe the primary cycle (number of root-hair infections) and 20, 30, and 40 days after inoculation to observe of the secondary cycle (frequency of infected cells and degree of plasmodial development based on the number of nuclei in infected cells). Although more root hairs were infected in HG than in YMG, fewer cells in root tissues including the cortex and medullary rays were infected in HG than in YMG. In addition, YMG developed plasmodia with many nuclei and formed resting spores, whereas plasmodia remained immature with a small number of nuclei in HG and did not form resting spores even by 40 days after inoculation. These results suggest that suppression of plasmodial development during secondary colonization is associated with resistance mechanisms to HG in cv. Kukai 70. Starch did not accumulate (i.e., development of amyloplasts) in HG-infected cells. This may be involved in the suppression of secondary colonization of P. brassicae in the cultivar.     

Organochlorine pesticide residue in Chinese herbal medicine

Over ten-year routine inspection results on organochlorine pesticide (OCP) residue were summarized, OCPs residues, including BHC isomers (α, β, γ, and δ-BHC), DDT analogs (p,p′-DDD, p,p′-DDE, o,p′-DDT, and p,p′-DDT), and pentachloronitrobenzene (PCNB) and its metabolites (pentachloroaniline and methyl pentachlorophenyl sulfide (MPCPS)), in 1,665 samples for 37 types of Chinese herbal medicine (CHM) using the QuEChERS method coupled with the GC-ECD. Based on the maximal residue levels for OCPs set by Asian pharmacopeias, PCNB contamination in Ginseng radix as well as the total DDT and PCNB contamination in Panacis quinquefolii radix are of concern. OCP residues in different parts of Panax ginseng were also compared. The total BHC residue in leaf and fibrous root, as well as the total DDT and PCNB residue in all parts, exceeded MRL of 0.1 mg/kg. Overall, this study provided meaningful results about OCP residue in CHM for pharmaceutical industries and consumers.     

小菜蛾为害不同生育期秋甘蓝对产量的影响及经济阈值研究

采用笼罩法测定了小菜蛾在秋甘蓝不同生育期为害造成的产量损失,建立了产量损失率与小菜蛾虫口密度的回归关系式。结果表明,在秋甘蓝苗期、莲座期、结球始期和结球中后期秋甘蓝损失率(y)与小菜蛾虫口密度(x)关系式分别为:y=9.480 6x-2.586 2,y=3.621 8x-0.790 2,y=-0.210 7x2+6.698 1x-1.906 5和y=0.081 1x2-0.147 9x+0.405 4。根据经济阈值模型,秋甘蓝不同生育阶段的小菜蛾幼虫经济阈值分别为苗期0.54头/株,莲座期0.91头/株,结球始期0.67头/株,结球中后期6.08头/株。该研究为秋甘蓝小菜蛾的防治策略和经济阈值的确定提供了科学依据。     

胺鲜酯在大白菜和土壤中的残留分析及消解动态

建立了胺鲜酯在大白菜及土壤中的残留分析方法。样品经乙酸乙酯提取、N-丙基乙二胺(primary secondary amine,PSA)和石墨化碳黑(graphitized carbon black,GCB)分散固相萃取净化后,采用气相色谱-质谱(GC-MS)检测,外标法定量。结果表明:当胺鲜酯在大白菜和土壤中的添加水平在0.005~0.05 mg/kg时,其回收率分别为83.2% ~103.2%和83.0% ~98.5%,相对标准偏差(RSD)分别为3.0% ~4.8%和3.8% ~11.3%。在土壤和大白菜中胺鲜酯的检出限为0.001 mg/kg,定量限为0.005 mg/kg。田间试验结果表明,胺鲜酯在大白菜和土壤中的半衰期分别为0.3~1.1 d和1.5~1.6 d,在大白菜中的最终残留小于0.06 mg/kg。     

大白菜抗芜菁花叶病毒的QTL分析

 以大白菜高抗TuMV-C₃株系的高代自交系A52-2和感病自交系GCⅣ杂交的F₂代255个单株作为构建遗传图谱的作图群体,通过EST-PCR-RFLP和AFLP分子标记的遗传分析,构建了包含12个连锁群,由124个遗传标记组成的大白菜分子遗传图谱。其中包括6个EST-PCR-RFLP多态性位点和118个AFLP多态性位点,该图谱覆盖长度为683.9 cM,平均图距5.52 cM。利用Windows QTL CartographerV 2.0软件和复合区间作图法进行分析,共检测到4个抗TuMV-C₃株系的QTLs位点。     

津黑两地大白菜褐腐病病原菌鉴定及生物学特性的比较

采用形态特征观察、致病性测定及rDNA-ITS序列分析等方法对天津、黑龙江两地大白菜褐腐病的病原菌进行鉴定。结果表明,天津、黑龙江两地大白菜褐腐病的病原菌为立枯丝核菌(Rhizoctonia solani Kühn),分离鉴定出TJ和DB两个菌株,分属立枯丝核菌AG-2融合群和AG-1融合群;DB菌株为一新菌株。两菌株菌丝生长最适温度均为25℃,最适pH为7,最适光照为12h。DB菌株菌丝生长速率快于TJ菌株;但TJ菌株先于DB菌株形成菌核,且形成量多。两菌株在碳源、氮源利用和菌核致死温度上也存在差异。     

Variability of pesticide residues in crop units

The results of 89 new field trials and 11 supervised trials were considered, together with 91 sets of residue data evaluated earlier. The datasets consisted of 22,643 valid residue data. As all variability factors calculated from individual sample sets are affected by the uncertainties of sampling and analysis, the average of the P(0.975)/R(ave) (97.5th percentile of the residue population divided by the average residues in the lot) values gives the best estimate for the variability factor. The Harrell-Davis (H-D) method gave an average value of 2.89 for the variability factor for all samples, while the average variability factors obtained from samples derived from the new field and supervised trials were 2.8 and 2.7 with the IUPAC and H-D methods respectively. The number of residue values below the LOQ in a sample set significantly affects the observed variability factors. It was found that datasets containing over 20% non-quantifiable residues might not reflect the true variability of the residues. Mixing of treated and non-treated commodities may significantly increase the apparent variability. Consequently, only datasets of known origin and consisting of well-quantifiable residues should be used for estimation of the variability factor. Samples taken from marketed lots may not represent a single lot, and thus they have limited value in estimating the variability factor. The large number of residue data confirms the applicability of the default variability factor of 3 adopted by the FAO/WHO for deterministic estimation of the acute intake of pesticide residues.     

Comparative effect of integrated pest management and farmers' standard pest control practice for managing insect pests on cabbage (Brassica spp.)

BACKGROUND: Studies were conducted on experimental cabbage plantings in 2009 and on experimental and commercial plantings in 2010, comparing farmers' current chemical standard pesticide practices with an integrated pest management (IPM) program based on the use of neem (Aza‐Direct) and DiPel (Bacillus thuringiensis). In experimental plantings, the IPM program used six or eight applications of neem and DiPel on a rotational basis. The standard‐practice treatments consisted of six or eight applications of carbaryl and malathion or control treatment. RESULTS: The IPM treatments reduced pest populations and damage, resulting in a better yield than with the standard chemical or control treatment. When IPM treatment included three applications of neem plus three applications of DiPel (on a rotational basis in experimental fields), it again reduced the pest population and damage and produced a better yield than the standard practice. The lower input costs of the IPM program resulted in better economic returns in both trials. CONCLUSIONS: The IPM components neem and DiPel are suitable for use in an IPM program for managing insect pests on cabbage (Brassica spp.). Copyright © 2011 Society of Chemical Industry     

两种生物农药防治菜心黄曲条跳甲的研究

黄曲条跳甲 Phyllotreta striolata 是为害十字花科蔬菜的重大害虫?本文研究了种子丸粒化包衣?拌土撒施和叶面喷雾3种施药方式下苏云金杆菌 Bacillus thuringiensis G033A和金龟子绿僵菌 Metarhizium anisopliae CQMa421对为害菜心 Brassica campestris L. ssp. chinensis var. utilis 的黄曲条跳甲的防治效果?结果表明, 采用苏云金杆菌G033A和金龟子绿僵菌CQMa421进行种子丸粒化包衣处理的菜心, 叶片受害指数分别为6.71和9.93, 显著低于对照(31.79); 拌土撒施处理的菜心, 叶片受害指数分别为19.34和24.17, 显著低于对照(65.53); 〖JP+1〗叶面喷雾处理后第3?5?7天的校正防治效果分别为58.95%/52.37%?69.56%/64.04%和81.12%/70.09%?本研究探索了菜心生产中主要害虫的生物防治技术, 研究结果将为菜心生产过程黄曲条跳甲的有效防治提供技术支撑?     

7种包衣剂对菜薹及黄曲条跳甲的影响初报

为明确7种种衣剂对菜薹的安全性及对黄曲条跳甲的防控作用,为黄曲条跳甲的有效防控提供技术支持,采用田间试验研究了乙基多杀菌素、Bt、啶虫脒、唑虫酰胺、虫螨腈、高效氯氟氰菊酯+虫螨腈、高效氯氟氰菊酯+啶虫脒等7种药剂对菜薹出苗、株高、鲜重的影响及对黄曲条跳甲的防控作用。结果表明,7种种衣剂对菜薹安全。除高效氯氟氰菊酯+虫螨腈、高效氯氟氰菊酯+啶虫脒外,其他5种药剂对黄曲条跳甲均具有一定的防控效果,以唑虫酰胺防治效果最好,平均防效高于82%,植株受害率较低,小于5%。     

大白菜抗感品种间作提高感病品种抗病毒病能力研究

为了探讨通过抗感品种间作栽培方式来提高大白菜品种抗病毒病的能力,采用小区试验和对黑龙江大白菜区试与生试结果分析。结果表明,抗感品种间作可提高感病大白菜品种抗病毒病能力;抗性不同的品种间作使同一品种在区试、生试中表现出不同的抗性,与对照相比表现出不同增产幅度。     

春夏大白菜黑斑病病原鉴定和抗性鉴定方法比较

为大白菜抗黑斑病新品种选育和种质创新,对陕西省春夏大白菜黑斑病进行调查、病样采集、病菌分离及形态和分子鉴定。结果表明,甘蓝链格孢Alternaria brassicicola是唯一病原。利用3个不同抗性的白菜品种研究了孢子浓度、苗龄和温度对大白菜黑斑病发病的影响,建立了大白菜抗甘蓝链格孢黑斑病的人工接种鉴定方法,即采用二叶期幼苗,以1×104pfu/mL孢子浓度喷雾接种,随后置25℃条件下,先黑暗下保湿24h,接着正常管理3天,从第4天开始夜间保湿,白天揭开,第8天保湿24h后调查发病情况,其结果客观反映大白菜品种的抗病性能。     

pHBA对菜心炭疽病的诱导抗性及植株生理特性的影响

 以菜心品种为材料,设置不同浓度对羟基苯甲酸(pHBA)处理,并通过人工接种炭疽病菌,研究pHBA对菜心炭疽病的诱导抗性作用机理。结果表明,在菜心生长发育过程中根系可以分泌出pHBA。pHBA对菜心的生长、产量形成和炭疽病的发生有明显的影响。适宜浓度的pHBA处理可促进菜心生长,提高植株对炭疽病的抗性,显著地降低病情指数(DI),提高菜薹产量,但当pHBA积累到一定浓度时,就对菜心植株产生自毒作用,提高DI和降低菜薹产量。炭疽病菌的感染破坏了植株细胞膜,增强细胞膜透性水平,诱导产生病程相关蛋白(几丁质酶、β-1,3-葡聚糖酶)和细胞壁物质(木质素、富含羟脯氨酸糖蛋白(HRGP))。适宜浓度的pHBA处理可抑制炭疽病菌对细胞膜透性的伤害,加强诱导提高几丁质酶活性、β-1,3-葡聚糖酶活性、木质素含量和HRGP含量,引起细胞壁木质化加强,增加了菜心植株对炭疽病的诱导抗病能力,从而阻止病原菌进一步侵入和扩散,抑制炭疽病菌对菜心产量造成的损失。     

The role of altered acetyl-CoA carboxylase in conferring resistance to fenoxaprop-P-ethyl in Chinese sprangletop (Leptochloa chinensis (L.) Nees)

From paddy field observations in 2002 and 2004, fenoxaprop-P-ethyl resistance in Chinese sprangletop (Leptochloa chinensis (L.) Nees) has been studied using information collected from 11 sites in the Saphan-Sung district of Bangkok, Thailand. The resistant Chinese sprangletop was found in nine rice fields, whereas the susceptible Chinese sprangletop was found in only two rice fields. In greenhouse experiments, both fenoxaprop-P-ethyl-resistant and susceptible Chinese sprangletop from the same location were investigated for 50% growth reduction based on phytotoxicity, plant height and fresh and dry weight. The resistant Chinese sprangletop showed apparent resistance at 14-21 days after herbicide application at a rate of 21.1-337.6 g AI ha(-1). The resistance index of resistant Chinese sprangletop was 10-25 times higher than that of the susceptible Chinese sprangletop. In addition, Chinese sprangletop did not exhibit multiple resistance to oxadiazon, propanil and quinclorac. According to acetyl-CoA carboxylase (ACCase) assays, the level of ACCase specific activity in the resistant Chinese sprangletop was significantly higher than that in the susceptible Chinese sprangletop. Similarly, the ACCase activity of the resistant Chinese sprangletop was 10 times less sensitive to fenoxaprop-P-ethyl than that of the susceptible Chinese sprangletop, based on the I50 values. The present study of the mechanism responsible for resistance in the biotypes investigated indicated that there was a close association between the concentration-response at the whole-plant level and ACCase sensitivity to fenoxaprop-P-ethyl, and resistance to fenoxaprop-P-ethyl was conferred by a modified ACCase at the target site, as suggested by higher specific activity and less sensitivity to the herbicide.     

结球白菜和拟南芥防御素基因的鉴定与比较分析

 植物防御素是一类富含半胱氨酸的小分子蛋白,在抗病反应中起着重要作用。本研究以结球白菜和拟南芥基因组序列为材料,利用生物信息学手段进行基因鉴定、染色体定位和进化分析。结果表明,结球白菜有11个防御素基因成员,数量少于拟南芥(15个),基因组DNA全长183~637 bp,开放阅读框全长183~363 bp;除结球白菜Bra029208序列外,其余防御素基因均有1个内含子;基因定位结果表明,一些基因成簇分布,推测由串联重复所致,拟南芥的3号、结球白菜的1、4、5和10号染色体均没有防御素基因的分布;进化分析结果表明,26个防御素成员可分为三大类,Ⅰ类有10条序列,Ⅱ类13条,Ⅲ类最少,仅3条。     

Metabolomic fingerprint of cabbage resistance to Mamestra brassicae L. (Lepidoptera: Noctuidae)

BACKGROUND

Plants defend themselves from insect feeding by activating specific metabolic pathways. We performed a metabolomic analysis to compare the metabolome reorganization that occurs in the leaves of two genotypes of cabbage (one partially resistant and one susceptible) when attacked by Mamestra brassicae caterpillars.

RESULTS

The comparison of the metabolomic reorganization of both genotypes allowed us to identify 43 metabolites that are specifically associated with the insect feeding response in the resistant genotype. Of these, 19% are lipids or lipid-related compounds, most of which are modified fatty acids. These include glycosylated, glycerol-binding and oxidized fatty acids, the majority being associated with the oxylipin pathway. Some of the identified lipids are unlikely to be produced by plants and may be the result of biochemical reactions in the caterpillar oral secretions. A further 16% are phenylpropanoids. Interestingly, some phenylpropanoids were not present in the susceptible genotype, making them possible candidates for specific resistance-related compounds.

CONCLUSION

Our results suggest that glucosinolates do not have a clear role in the resistance to M. brassicae feeding on cabbage. Using an untargeted metabolomics approach, we associated the regulation of metabolic pathways related to lipid signalling and phenylpropanoid compounds with the resistance to this pest. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

鼠李糖脂改性生物炭对盐渍土小白菜抗性及氮素吸收的影响

为探究鼠李糖脂改性生物炭对盐渍土的改良效果,通过小白菜盆栽试验,以盐渍土壤为材料,按照占土壤质量1%和2%比例各添加4种浓度的鼠李糖脂改性生物炭（浓度为250 mg·L^-1的鼠李糖脂体积(V)占生物炭质量(m)比分别为15%、10%、5%、0%）,研究了鼠李糖脂改性生物炭对盐渍土性质、氮素养分吸收以及小白菜生长和酶活性的影响。结果表明,与对照相比,鼠李糖脂改性生物炭提高了土壤有机碳含量和土壤铵态氮、硝态氮含量,但对土壤pH值无显著影响,其中,施加鼠李糖脂改性生物炭的处理与对照相比有机碳含量显著增加了55.05%~142.67%,施加鼠李糖脂改性生物炭比例为10%的处理平均与对照相比铵态氮含量显著提高了156.69%,施加鼠李糖脂改性生物炭比例为15%、10%的处理与对照相比硝态氮含量平均分别显著增加了37.94%、41.46%。施用鼠李糖脂改性生物炭显著增加了小白菜生物量和吸氮量,其中,改性比例为10%的处理平均分别比单施生物炭的处理增加了47.13%和43.64%。施用鼠李糖脂改性生物炭提高了叶片谷氨酰胺合成酶和过氧化物酶的活性,提高了可溶性蛋白含量,降低了丙二醛含量,其中,施加鼠李糖脂改性生物炭比例为10%的处理平均与对照相比叶片谷氨酰胺酶活性显著提高了113.64%、过氧化物酶活性显著提高了30.87%,施加鼠李糖脂改性生物炭比例为10%和5%的处理平均分别与对照相比可溶性蛋白含量提高了7.59%和37.60%,施加鼠李糖脂改性生物炭比例为10%的处理平均与对照相比丙二醛含量显著降低了80.60%。总体看来,采用鼠李糖脂改性的生物炭可以提高盐渍土小白菜的抗性,促进其对氮素的吸收,且以改性比例为10%效果最佳。     

直接竞争酶联免疫吸附分析法测定小白菜中溴氰菊酯的残留量

应用作者所在实验室自制的、对溴氰菊酯具有特异性亲和力的多克隆抗体和酶标半抗原,建立了包被抗体-酶标半抗原直接竞争酶联免疫吸附分析法(DC-ELISA)。小白菜样品经超声提取、浓缩和10%甲醇定容后采用DC-ELISA法测定,并采用高效液相色谱法进行验证。结果表明:在抗体包被浓度为2.0 mg/L、辣根过氧化物酶(HRP)标记溴氰菊酯半抗原稀释2.0×105倍、包被介质为pH 7.2 PB、反应介质为含0.125 mol/L NaCl pH 6.8 PB的优化条件下,DC-ELISA法检测溴氰菊酯的线性范围为0.10~10 mg/L,溴氰菊酯对抗体-酶标半抗原反应的抑制中浓度(IC50)为1.68 mg/L,相对标准偏差(RSD,n=5)为2.11%,IC10值为0.16 mg/L。在5、1和0.2 mg/kg 3个添加水平下,DC-ELISA法测定小白菜中溴氰菊酯的平均回收率分别为97%、106%和95%,RSD(n=5)分别为8.5%、8.1%和8.1%。高效液相色谱法同步测定小白菜中添加0.2 mg/kg溴氰菊酯的回收率为107%。本研究建立的DC-ELISA法可用于小白菜中溴氰菊酯含量的快速测定。     

Effects of pesticide residues on ground-dwelling lycosid and micryphantid spiders in laboratory tests

The effects of residues of three commercial pesticides in common use in Europe against cereal pests, on two dominant spider species, a lycosid and a micryphantid, were evaluated in the laboratory. Insecticide assay methods for juvenile and adult hunting and adult web-building, ground-dwelling spiders are described. Results varied with different sprayed substrates and species. Fenvalerate was more toxic than other pesticides and had a longer residual effect on all spiders when tested on moistened sand than on filter paper. Endosulfan was of high initial toxicity on sand, but was more toxic on filter paper to both adults and juveniles ofPardosa spp. Pyrazophos was non-toxic to the spiders tested, regardless of substrate. In general, the lycosids were more affected by pesticides than web-building spiders because of their different life strategies. A sprayed sand substrate matched field conditions better as a method to test the effects of pesticides on ground-dwelling spiders.