Resistance of Grafted Tomato with Guozhen 1 as Stock against Root Knot Nematodes in Field

[Objective] This study aimed to study the resistance of grafted tomato with Guozhen 1 as stock against root knot nematodes. [Method] Tomato seedlings were grafted with Guozhenl （T1） and Solanum torvum （T2） as the rootstock, respectively. Self-rooted tomato seedlings were treated as the control （CK）. The resistance of tomato against root knot nematodes was compared among the three treatments. [Result] Compared with those in the T2 and CK groups, the yield of tomato in the T1 group was increased by 17 436.75 and 31 753.65 kg/hm2 respectively, the plant height was increased by 10.55 and 14.54 cm respectively （P〈0.05）, and the stem diameter was increased by 0.56 and 1.13 cm respectively （P〈0.05）. The disease indexes of root knot nematodiasis in the three treatments were 0.55, 10.42 and 45.31, respectively, and there were significant differences among them （P〈0.05）. [Conclusion] This study will provide a theoretical basis for the control of root knot nematodes in tomato by grafting.

Occurrence of Root-Knot and Reniform Nematodes in Ornamental Plants Grown in Aligarh Muslim University Campus, India

An extensive survey of about 50 ornamental plants growing in A.M.U. campus were carried out to find out the infection of root-knot (Meloidogyne spp.) and reniform nematodes (Rotylenchulus reniformis). Out of 50 species of ornamental plants studied, 29 species of these plants were found to be infected with root-knot nematodes (Meloidogyne spp.) and 15 species were infected with reniform nematode (Rotylenchulus reniformis). The highest percentage of infection of root-knot nematodes was observed in Impatiens balsamina (100%) and reniform nematode was observed in Hibiscus rosa-sinensis (56%). Among the Meloidogyne spp. the highest percentage of infection of M. incognita was observed in Pseuderanthemum atropurpureum (80%) whereas, the highest percentage of infection of M. javanica and M. arenaria was observed in Mirabilis jalapa (72%) and Celosis cristata (28%).

Effect of Anti-nematode Preparations on Physiological Traits of Tomato Leaves Affected by Root-knot Nematode

[ Objective ] The paper was to study the effects of anti-nematode preparations with different mechanisms on changes of enzyme systems and membrane permeability of tomato leaves, so as to provide reference basis for effective control of soil root-knot nematode in greenhouse. [ Method] With tomato seedlings af- fected by root-knot nematode as material, changes of superoxide dismutase（SOD）, peroxidase（ POD）, relative conductivity and malondialdehyde （MDA） in toma- toes were tested after the seedling soil was treated by preparations of Wuxianmei, Hailvsu, Duxiandna and Avermectin. [ Result] After treated by different prepara- tions, SOD and POD activity of tomato leaves were higher than control, and that treated by Wuxianmei was the highest. In addition to Duxiandna, the relative con- ductivity and MDA content of other treatments were significantly lower than control. When tomatoes were planted for 70 d, the effect of Avermectin against reot-knot nematode Was the best of 66.3%. [ Conclusion] After tomatoes were infected by root-knot nematode, different preparation treatments all had certain control effect, which made the physical indicators of tomato have obvious change. Integrated control of multiple preparations in greenhouse was beneficial to control soil root-knot nematode.

The synergistic advantage of combining chloropicrin or dazomet with fosthiazate nematicide to control root-knot nematode in cucumber production

The highly-damaging root-knot nematode(Meloidogyne spp.,RKN)cannot be reliably controlled using only a nematicide such as fosthiazate because of increasing pest resistance.In laboratory and greenhouse trials,we showed that chloropicrin(CP)or dazomet(DZ)synergized the efficacy of fosthiazate against RKN.The combination significantly extended the degradation half-life of fosthiazate by an average of about 1.25 times.CP or DZ with fosthiazate reduced the time for fosthiazate to penetrate the RKN cuticle compared to fosthiazate alone.CP or DZ combined with low or medium rate of fosthiazate increased the total cucumber yield,compared to the use of each product alone.A low-dose fosthiazate with DZ improved total yield more than a low dose fosthiazate with CP.Extending the half-life of fosthiazate and reducing the time for fosthiazate or fumigant to penetrate the RKN cuticle were the two features that gave the fumigant-fosthiazate combination its synergistic advantage over these products used singularly.This synergy provides the opportunity for farmers to use a low dose of fosthiazate which lowers the risk of RKN resistance.Farmers could combine DZ at 30 g m^-2 with fosthiazate at a low rate of 0.375 g m^-2 to control RKN and adequately control two major soil-borne diseases in cucumber greenhouses.

Effects of Two Composted Plant Pesticide Residues,Incorporated with Trichoderma viride,on Root-Knot Nematode in Balloonflower

Plant pesticide residues, such as chinaberry （Melia toosendan） residue and sand cypress （Sabina vulgaris） residue, are pesticidal plant materials discarded after the bioactive ingredient has been extracted with organic solvents. The only option for botanical pesticide residue utilization has been as landfill. Chinaberry residue （CBR） and sand cypress residue （SCR） were collected and composted in Yangling, Shaanxi Province, China. We studied the effects of chinaberry residue compost （CBRC）, CBRC incorporated with Trichoderma viride （CBRCT）, sand cypress residue compost （SCRC）, and SCRC incorporated with T. viride （SCRCv） on the root-knot nematode, Meloidogyne incognita, infesting the balloonflower （Platycodon grandiflorum）. Bioassay results indicated that stock solutions of the CBRCT and SCRCT extracts significantly inhibited egg hatching and caused high larval mortality, followed in degree by the CBRC and SCRC extracts. The CBR and SCR extracts caused very low inhibition of eggs and larvae. Supplementing potting mixtures with these four composts reduced the severity of root galling and increased the proportion of marketable roots. The severity of root galling decreased and the average weight of the marketable roots increased with an increase in all the composts when supplemented at rates from 5 to 30%. CBR- and SCR-supplemented pot soils also inhibited the nematodes, but CBR and SCR applied to the soil had a phytotoxic effect and inhibited balloonflower growth. Supplementing field soil with the composts reduced the severity of root galling and the populations of southern root-knot nematodes in the soil. CBRCT and SCRCT clearly enhanced the average weight of the marketable roots by 30.45 and 26.64%, respectively. Continuous supplementation with CBRCT or SCRCT in the same field significantly enhanced the control of the root-knot nematode, and the populations of nematodes continued to decrease with second inoculations. The populations of total Trichoderma spp. were distinctly enhanced and were maintained at high levels for a long time in the supplemented soils.

Morphology and Molecular Identification of Root-knot Nematode in Partial Tobacco-growing Areas in Yunnan Province

[Objectives]The species and distribution of root-knot nematodes in tobacco growing regions of Yunnan were investigated,in order to provide reference for comprehensive prevention of root-knot nematodes disease and tobacco variety layout. [Methods]Fifty-four samples of root-knot nematode host on tobacco crops were collected from Kunming,Qujing and Yuxi cities in Yunnan from August to October in 2015. The species of root-knot nematodes were identified by observing perineal patterns and molecular biological testing（ PCR of ribosomal DNA of ITS region and sequence characterized amplified region,SCAR）. [Results] There were 24 samples belonging to Meloidogyne arenaria,accounting for 44. 44%; seven M. incognita samples,accounting for 12. 96%; one M. javanica sample,accounting for 1. 85%. Eleven samples were compound populations of M. javanica and M. arenaria,accounting for 20. 37%. Five were compound populations of M. incognita and M. arenaria,accounting for 9. 26%. Three were compound populations of M. incognita and M. javanica,accounting for 5. 56%. Three belonged to compound population of M. incognita,M. javanica and M. arenaria,accounting for 5. 56%. [Conclusions] The species of root-knot nematodes in tobacco growing areas of Yunnan mainly include M. incognita,M. javanica and M. arenaria. M. arenaria is the dominant population.

Bacterial artificial chromosome library construction of root-knot nematode resistant pepper genotype HDA149 and identification of clones linked to Me3 resistant locus

Pepper （Capsicum annuum. L.） is a widely cultivated vegetable crop worldwide and has the second largest planting area and the first largest vegetable output and value in China. Pepper root-knot nematode （Meloidogyne spp.） is one of the most serious pests of pepper, which caused huge losses every year. Previous studies showed that the Me3 gene is resistant to a wide range of Meloidogyne species, including M. arenaria, M. javanica, and M. incognita. HDA149, a double haploid pepper genotype, harboring the root-knot nematode resistance gene Me3, was used to construct bacterial artificial chro- mosome library （BAC） via the vector of CopyControFM pCC1 in this study. The library consists of 210 200 BAC clones and is equivalent to 5.3 pepper genomes. The average insert size is 95 kb, and most of them are 90-120 kb; but the empty clones are less than 3%. In order to screen the BAC library easily, 550 super pools with 384 BAC clones of each pool were further developed in this study. Specific primers from Me3 gene locus were used for BAC library screening, and more than 20 positive BAC clones were obtained. Then the selected positive BAC clones were analyzed by restriction enzyme digestion, BAC-end sequencing, marker development, and new positive BAC clones exploration, respectively. Finally, the contig with total length of about 300 kb linked to the Me3 locus was constructed based on chromosome walking strategy, which made a solid foundation for the cloning of the important root-knot nematode resistance gene Me3.

Preliminary Study on Mixed Use of Agaricus bisporus Residue and Microbial Agent to Control Cucumber Root-knot Nematode

Single or mixed use ofAgaricus bisporus residue and microbial agent had better control effect on cucumber root-knot nematode disease in greenhouse. The results showed that the control effect of single use of A. b/sporus residue was 32.9% - 34.7%, and the yield increasing rate was 2.1% - 8.7% ; the control effect of mixed use ofA. b/sporus residue and microbial agent was 59. 1% - 63. 6%, and yield increasing rate was 2.6% - 3.5%. The experimental dose had no ad- verse effects on soil physical and chemical properties. The mixed use of A. b/sporus residue and microbial agent was one of the effective ways to control root-knot nematode disease.

RNAi of <i>MiASB</i>caused high mortality of <i>Meloidogyne incognita</i>juveniles and inhibited the nematode disease

The southern root-knot nematode, Meloidogyne incognita, is one of the most prevalent and damaging plant-parasitic nematodes in the world and causes serious damages to agricultural production. We cloned a mitochondrial ATP synthase b subunit gene fragment of M. incognita (MiASB) based on the nematode genomics prediction. By soaking in the MiASB dsRNA solution, the hatching of RNAi treated eggs was reduced by 60% compared to negative control and by 64% compared to untreated control. Mortality of RNAi treated second stage juvenile (J2) was 8.6 times higher than that of negative control and 26 times higher than the untreated control. Inoculating the RNAi treated egg masses and J2 to tomato seedlings showed the pathogencity was significantly reduced. For the RNAi treated egg masses, the amount of root galls on silence treated seedlings was reduced by 92% compared to that on the negative control seedlings, and reduced by 93% compared to that on untreated control seedlings. For the treated J2, the amount of root galls on silence treated seedlings was reduced by 83% and 86% compared to negative and untreated control seedlings, respectively. The study revealed the MiASB silence had a positive effect on prevention and control of root-knot nematode disease, and also showed that the MiASB may be involved in the pathogenesis of nematode, which provided new ideas and ways to the research of nematode pathology and nematode disease control.

中国北方稻田及其周边环境中根结线虫种类鉴定

【目的】了解我国北方稻田及其周边环境中根结线虫的种类,为进一步制定水稻根结线虫病的防治策略提供参考。【方法】2020和2021年春季从我国河南、山东、宁夏、北京、吉林、黑龙江、新疆、甘肃、河北、辽宁、山西、陕西和内蒙古13个省(直辖市/自治区)的连片稻田、周围田埂、旱地等采集了1032份土样,每份土样与灭菌河沙混合后平均分成3等份分别放入花盆中,盆中一半播水稻一半播番茄,50 d后检测水稻或番茄根系是否有根结产生。挑取阳性样品根结中的雌成虫,制作会阴花纹玻片,对根结线虫种类进行形态鉴定;同时利用我国常见6种根结线虫特异性引物对土样中的根结线虫种类进行分子鉴定。【结果】生物测定结果显示,有119份土样能够引起水稻或番茄幼苗产生根结,总检出率为11.53%,其中宁夏回族自治区土样检出率最高,为33.33%。在根结线虫种类鉴定中发现,拟禾谷根结线虫(Meloidogyne graminicola)为北方水稻产区优势种,占鉴定样品的96.83%;花生根结线虫(M.arenaria)、北方根结线虫(M.hapla)、南方根结线虫(M.incognita)、象耳豆根结线虫(M.enterolobii)和爪哇根结线虫(M.javanica)分别占鉴定样品的84.13%,52.38%,31.75%,15.87%和3.17%。受1,2,3,4,5和6种根结线虫侵染的土样比例分别为11.11%,28.57%,28.57%,28.57%,3.18%和0%。其中最常见的为拟禾谷根结线虫、南方根结线虫、花生根结线虫和北方根结线虫混合侵染(23.81%),其次为拟禾谷根结线虫和花生根结线虫混合侵染(22.22%),再次为拟禾谷根结线虫、花生根结线虫和北方根结线虫混合侵染(15.87%),其他不同种类根结线虫混合侵染的田块比例不超过10.00%。【结论】根结线虫广泛分布于我国北方稻田及其周边环境中,其中拟禾谷根结线虫为优势种,象耳豆根结线虫也已适应低温由南向北扩散,今后应加大研究根结线虫在北方露地低温环境下的适应能力及扩散和危害风险,制定相应的防治措施。

广西水稻产区稻-菜轮作田水稻根结线虫病发生情况调查及病原鉴定

为了明确广西水稻产区稻-菜轮作田根结线虫发生情况及其病原分类地位,在广西14个市27个乡(镇)的171块水稻产区稻-菜轮作田进行了采样调查,并进行致病线虫分离,根据2龄幼虫形态、雌虫会阴花纹特征等,结合核糖体ITS区和28S rDNA D2D3区序列分析方法对病原线虫种类进行鉴定。结果表明,共有64个田块发生根结线虫为害,水稻种植季根结线虫检出率为37.4%,蔬菜轮作季根结线虫检出率为25.7%。广西水稻根结线虫病病原为拟禾本科根结线虫Meloidogyne graminicola。说明拟禾本科根结线虫病在广西稻-菜轮作田发生已经相当普遍,应当引起重视。

海南火龙果园土壤肥力与根结线虫数量调查

为了明确海南岛火龙果园土壤肥力状况和根结线虫危害情况,采集了海南岛68家火龙果园的土壤样品共204份,分析测定了土壤氮、磷、钾、钙、镁等矿质营养元素含量及根结线虫的数量,并采用模糊综合评判法对果园土壤综合肥力状况进行评价,分析了根结线虫数量与土壤养分状况的相关性。结果表明:海南岛火龙果园土壤pH为6.4,整体呈中性或弱酸性;有机质含量为19.9 g·kg^(-1),碱解氮含量为63.9 mg·kg^(-1),速效钾含量为95.8 mg·kg^(-1),均处于缺乏状态,而有效磷、交换性钙含量为丰富及以上等级,交换性镁处于中量水平;土壤pH与有机质、交换性钙、镁含量呈显著正相关,表明维持中性的pH水平有利于土壤有机质的积累,对钙、镁的有效性有重要意义;土壤有机质含量与碱解氮、有效磷、速效钾、交换性钙、镁含量呈显著正相关,说明土壤有机质的提高有助于提升土壤基础矿质养分的含量;各火龙果园根结线虫数量差异较大,其中,每100克干中土根结线虫2龄幼虫(J2)数量最多的可达736条,而较少的仅有14条;根结线虫发生轻重情况南北差异较大,整体上北部地区的火龙果园根结线虫数量低于南部地区;土壤pH、有机质、有效磷、交换性钙与根结线虫数量呈正相关。调查结果显示,海南岛火龙果园土壤综合肥力指数处于较高水平。

寡糖联合淡紫紫孢菌对化学杀线剂防治烤烟根结线虫病效果的影响

为更好地控制烟草根结线虫的危害,降低化学杀线剂的用量,将寡糖免疫诱导剂与噻唑膦、阿维菌素及淡紫紫孢菌协同使用进行田间小区试验,研究其对烟草根结线虫的防治效果。结果表明,壳寡糖15 L/hm^(2)、几丁寡糖15 L/hm^(2)分别与噻唑膦22.5 kg/hm^(2)协同使用,对烟草根结线虫的防治效果高于噻唑膦单独使用效果。相对防效由噻唑膦单独使用的45.20%分别提高到64.42%和65.38%。进一步试验发现,几丁寡糖1 kg/hm^(2)、淡紫紫孢菌15 kg/hm^(2)及噻唑膦16.875 kg/hm^(2)(减少25%)协同使用,对烟草根结线虫病相对防效及对烟草生长总体效应优于与噻唑膦正常用量(22.5 kg/hm^(2))组和噻唑膦减少50%(11.25 kg/hm^(2))组合效果。寡糖诱导剂单独或与淡紫紫孢菌协同使用,显著提高了噻唑膦对烟草根结线虫病的防治效果,减少了农药使用量,为烟草根结线虫病害的防控提供了一种新的技术手段。

生物炭肥对易感根结线虫病烤烟根际菌群和理化性质的影响

为明确生物炭肥对烟草根结线虫病及根际土壤的影响,通过田间试验研究拌塘施用不同量生物炭肥对烟草根结线虫病株根际土壤的影响。结果表明,常规施肥减量10%拌塘施用酵素生物炭肥能够显著降低烟草根结线虫病的病情指数,其中酵素生物炭肥施用量为350 g·株^(-1)时,根结线虫病防治效果较好,防治效果达23.98%,且烟株农艺性状表现较好;根际土壤中过氧化氢酶、脲酶和磷酸酶活性较高,酚酸物质含量降低,化感自毒作用减弱。各处理土壤真菌数量均随生育期的推进呈先增高后降低趋势,其中酵素生物炭肥施用量为350 g·株^(-1)时,根际土壤中的细菌量随生育期推进逐步降低。各生育期土壤中均表现为真菌数量较高,细菌数量较低,真菌/细菌值较高,说明在烟草种植中,减量施肥10%同时拌塘施用酵素生物炭肥350 g·株^(-1)能提高土壤中真菌数量,降低土壤中细菌数量,显著提高土壤肥力及土壤酶活性,为生物炭肥对易感根结线虫病根际微生态调控提供了科学依据。

作物根结线虫病化学防治研究进展

根结线虫Meloidogyne spp.是严重威胁农业生产的重要病原生物,对世界上大多数作物都存在负面影响。在我国,随着保护地栽培模式的扩大及作物复种指数的不断提高,根结线虫病的发生日趋严重,而目前的管理措施尚不能完全控制根结线虫的危害。使用化学杀线虫剂仍然是目前防治根结线虫最常见的短期管理策略。本文总结了目前我国作物根结线虫病的发生现状,介绍了生产中防治该病害的主要化学药剂,分析了其化学防治存在的主要问题,并讨论了目前化学杀线虫剂及其应用技术的优化;展望了未来根结线虫化学防治的研究方向;提出根结线虫的化学防治应该与其他管理措施相结合,实现根结线虫高效、安全、可持续发展的综合治理。

根结线虫病对烟草植株根际土壤微生物群落及其功能的影响

为明确烟草植株根际土壤微生物对烟株根结线虫病的响应特征,采用Illumina MiSeq高通量测序技术测定健康烟株(FH-H)、发病烟株(FH-D)根际土壤细菌16S rDNA和真菌内转录间隔区(ITS)序列,测定其根际土壤理化性质和酶活性,并借助PICRUSt2软件和FUNGuild数据库进行分析。结果表明,与健康烟株相比,发病烟株根际土壤pH、硝态氮含量、碱解氮含量、过氧化氢酶活性和微生物群落α多样性显著降低;发病烟株根际土壤微生物种类和相对丰度发生改变,细菌群落中放线菌门、厚壁菌门、芽孢杆菌属和Unclassified_Ktedonobacteraceae属相对丰度均显著升高,真菌群落中子囊菌门、担子菌门、青霉属、粗糙孔菌属相对丰度均显著升高。发病烟株根际土壤细菌群落在碳水化合物代谢、氨基酸代谢、辅助因子和维生素代谢等功能丰度上显著高于健康烟株根际土壤,功能真菌类型的相对丰度明显区别于健康烟株根际土壤,其中腐生营养型功能真菌相对丰度显著高于健康烟株根际土壤。方差分解分析结果表明,土壤有效磷含量对烟株根际土壤细菌相对丰度影响最大,烟株根际土壤真菌相对丰度主要与土壤脲酶活性、土壤硝态氮含量和土壤酸碱度有显著相关性。本研究结果为根结线虫病的绿色防控和土壤保育提供了理论依据。

宛氏拟青霉提取物与阿维菌素配施对番茄根结线虫病的防治效果

为明确宛氏拟青霉提取物(ZNC)对番茄根结线虫病的防治潜力,采用盆栽试验,以清水为对照,研究ZNC(0.5、1.0μg·株-1灌根)、阿维菌素(5 mg·株-1底施处理)及两者配施对番茄生长和果实品质的影响及其对根结线虫病的防治效果。结果显示,与清水处理相比,ZNC能够显著提高番茄根质量,降低根结数量,同时能够显著增加番茄的叶长、叶宽,提高番茄的株高和地上部鲜质量,还可提升植株抗氧化能力和果实品质;与阿维菌素配施对番茄根结线虫病防效可达88.89%,显著高于阿维菌素单施,同时番茄生长状况和果实品质得到提升。表明ZNC能够促进番茄生长,与阿维菌素配施后可提高番茄根结线虫病的防治效果。

不同药剂对黄瓜根结线虫病的防治效果研究

为有效防治黄瓜根结线虫病,保证黄瓜安全生产,本试验选择10.5%阿维·噻唑膦颗粒剂、0.5%阿维菌素颗粒剂和10%噻唑膦颗粒剂等药剂进行了黄瓜根结线虫病的田间药剂防治试验。结果表明,施药40 d,每667 m^(2)用10.5%阿维·噻唑膦颗粒剂1500~1800 g和10%噻唑膦颗粒剂1800 g较其他处理防治效果显著,防治效果达到77%以上,药剂的持效期长;试验期间观察各药剂处理区黄瓜的叶片颜色、株型等,均未见药害,亦未见药剂处理促进或抑制黄瓜生长的现象,说明各药剂在试验用量下对黄瓜生长安全。建议生产中交替使用阿维·噻唑膦复配制剂和噻唑膦单剂,不仅能够有效防治黄瓜根结线虫病,还可以延缓抗药性的产生和发展。

生防菌剂与噻唑膦减量配施对番茄根结线虫及根际土壤微生物的影响

减少化学农药的使用,提高生物农药在田间使用效率对实现化学农药减施及农产品质量安全具有重要意义。本研究以番茄‘新金丰一号’为试验材料,采用盆栽接种根结线虫的方法研究噻唑膦与生防菌剂以不同剂量配施对番茄根结线虫的防效及对根际土壤微生物的影响。结果表明:噻唑膦减量50%配施50%生防菌剂处理后,土壤中的根结线虫数量和番茄根系的根结指数相比单独使用噻唑膦或生防菌剂及清水处理均显著降低,番茄移栽后60 d,根结线虫减退率为49.61%,根结指数为32.50,防治效果达64.77%。与仅用噻唑膦处理相比,噻唑膦减量50%配施50%生防菌剂处理还显著增加了番茄根际土壤中可培养细菌、放线菌数量及微生物的总量,其中细菌和放线菌数量较仅用噻唑膦处理增加76.21%和47.96%,微生物总量增加69.60%。此外,放线菌门、子囊菌门的相对丰度也显著增加,而酸杆菌门和芽胞杆菌门的相对丰度则正好相反。无论使用生防菌剂还是噻唑膦减量配施生防菌剂均显著增加了番茄根际土壤中髌骨细菌门、浮霉菌门和木霉属的相对丰度,但仅使用噻唑膦处理则显著降低了木霉属的相对丰度。综上,噻唑膦减量50%配施50%生防菌剂可通过增加番茄根际土壤中可培养微生物数量及放线菌门和木霉属等有益微生物的丰度来提高对番茄根结线虫的防效。

不同药剂对温室黄瓜根结线虫防效和黄瓜生长的影响

以内蒙古奈曼旗温室黄瓜根结线虫为研究对象,比较了枯草芽孢杆菌、淡紫拟青霉、厚垣轮枝菌及嗜小红卵菌HNI-14种生防药剂及化学药剂噻唑磷对根结线虫的防治效果和对黄瓜植株生长的影响。结果表明,4种生防药剂中淡紫拟青霉对黄瓜根结线虫防效最好,达76.10%。淡紫拟青霉对黄瓜植株的株高、茎粗、有效叶数、叶面积和根系活力均有促生作用。因此,淡紫拟青霉可推荐为该地区防治蔬菜根结线虫的可替换生防药剂。