美国大豆中镰刀菌的分离鉴定

为加强对美国输华大豆真菌病害的监测力度,降低外来生物入侵风险,本文通过对美国进境大豆病菌分离,共得到32个菌株,并对其中3株镰刀菌进行了形态学和分子生物学鉴定,确认了它们分别是尖孢镰刀菌(Fusarium oxysporum)、木贼镰刀菌(F.equiseti)和拟枝孢镰刀菌(F.sporotrichioides)。本研究从32个分离菌株中得到的3株镰刀菌分属于不同种,不仅证实了美国大豆中镰刀菌的多样性,也可为港口的植物检疫工作提供借鉴。     

河北廊坊大豆枯萎病病原镰刀菌的分子鉴定

 为明确河北廊坊中国农科院植保所试验基地大豆孢囊线虫病田内大豆枯萎病病原镰刀菌的种类,对362份罹病枯萎大豆植株进行病原真菌分离,得到335株真菌;使用镰刀菌通用引物鉴定出镰刀菌(Fusarium spp.) 279株,占分离菌株83.3%;镰刀菌特异性引物、测序等分子生物学技术结合形态学特征进一步鉴定镰刀菌种类,鉴定出尖孢镰刀菌(F. oxysporum)189株,占分离菌株56.4%;茄病镰刀菌(F. solani)67株占20.0%、禾谷镰刀菌(F. graminearum)16株占4.8%、木贼镰刀菌(F. equiseti)3株、层出镰刀菌(F. proliferaum)2株、燕麦镰刀菌(F. avenaceum)和厚孢镰刀菌(F. chlamydosporum)各1株;致病性测试结果表明数量最多的尖孢镰刀菌(F. oxysporum)中约92.8%菌株具有不同程度的致病力;这些结果表明该试验基地大豆枯萎病的优势病原菌为尖孢镰刀菌(F. oxysporum);研究结果可为大豆枯萎病的防治提供科学依据,并为大豆孢囊线虫与尖孢镰刀菌复合侵染大豆的研究奠定基础。     

水花生病原菌——蕉斑镰刀菌菌株的筛选及其致病性测定

蕉斑镰刀菌 Fusarium stoveri是从自然界水花生植株上分离的、可致水花生表现萎蔫、地上茎腐烂、叶片上呈现褐色斑或黄化的生防真菌.室内研究表明,蕉斑镰刀菌菌丝生长和产孢的适宜温度范围在25～28℃,多数菌株的最适温度为28℃;菌株间的产孢量有较大差异.在供试菌株中,32-6菌株的产孢量最大;供试的9个蕉斑镰刀菌菌株对水花生均有较强的致病力,但菌株间的致病力有所差异.根据菌株的生长速率、产孢量和致病力等因素,菌株32-6被选为水花生生防菌的优选菌株.采用生产上常见农作物、蔬菜、经济作物及物候上与水花生一致的杂草等42种植物对菌株32-6进行寄主专化性测定,结果表明,蕉斑镰刀菌菌株32-6具有高度的寄主专化性,只对水花生表现出较强的致病性,对其他植物均不致病.     

浙江省铁皮石斛根腐病病原真菌的鉴定

为明确铁皮石斛根腐病病原真菌,于其主产地浙江省金华市武义县收集铁皮石斛根腐病病株,采用平板分离方法对病原真菌进行分离,使用镰刀菌种特异性引物并结合ITS和TEF序列分析及形态学鉴定确定该镰刀菌的分类地位。结果表明,共分离纯获得真菌117株,其中有105株镰刀菌;经分子生物学分析及形态学鉴定结果显示,分离出的镰刀菌为层出镰刀菌Fusarium prolife‐mum、茄病镰刀菌F. solani、尖孢镰刀菌F. oxysporum和厚垣镰刀菌F. chlamydosporum四个种,其中层出镰刀菌在数量上具有优势地位,占总镰刀菌数的44.8%;茄病镰刀菌、尖孢镰刀菌、厚垣镰刀菌分别占总镰刀菌数的21.0%、15.2%和19.0%。在致病性测定中发现层出镰刀菌和茄病镰刀菌并不具备致病性,尖孢镰刀菌的致病性明显弱于厚垣镰刀菌,表明厚垣镰刀菌为浙江省金华市武义县铁皮石斛根腐病的主要致病菌。     

烟草尖孢镰刀菌拮抗真菌的筛选鉴定及促生作用研究

为获得烟草镰刀菌根腐病拮抗真菌菌株,试验以河南省豫中烟区烟草根际土壤为试材,以主要致病菌尖孢镰刀菌Fusarium oxysporum为主要靶标,采用稀释涂布平板法分离获得土壤真菌371株,平板对峙培养法测定获得1株具有明显抑制效果的拮抗菌株,利用形态学和分子生物学的方法将其鉴定为棘孢木霉Trichoderma asperellum Tr-0111。抑制效果测定表明,该菌株对尖孢镰刀菌的抑制率最高可达93.13%,对根串珠霉菌、拟茎点霉、链格孢菌等其他8种烟草病原菌均具有较强的抑制效果。促生作用测定结果表明,菌株发酵液使烟草种子萌发率提高5.34%,烟苗根长增长率为62.39%,对盆栽烟草的最大叶面积和地上部鲜重也具有显著的促生效果。为进一步相关机理的研究和生防菌剂的研制奠定了基础。     

黑龙江省马铃薯干腐病菌种类鉴定及致病性

本研究将采自黑龙江省不同地区的马铃薯干腐病病样进行分离和病原菌纯化,得到27个镰刀菌菌株,通过致病性鉴定,其中的18个菌株具有致病性。运用培养性状和形态特征综合分析的方法,对上述18个菌株进行鉴定,结果显示为6种镰刀菌,分别为拟枝孢镰孢(Fusarium sporotrioides)、茄镰孢(F.solani)、接骨木镰孢(F.sam-bucinum)、拟丝孢镰孢(F.trichothecioides)、燕麦镰孢(F.avenaceum)和茄病镰孢蓝色变种(F.solanivar.coerule-um)。同时对上述6种镰刀菌进行致病性测定,结果表明不同种类镰刀菌致病性不同,以接骨木镰孢、燕麦镰孢和拟丝孢镰孢致病力最强,拟枝孢镰孢致病力最弱。     

宁夏回族自治区马铃薯镰刀菌根腐病病原菌的分离鉴定与致病性测定

为明确宁夏回族自治区马铃薯镰刀菌根腐病的病原菌种类,2015—2018年从宁夏回族自治区固原市、吴忠市、中卫市和石嘴山市4个市12个区县采集马铃薯病样,采用组织分离法对病样进行分离纯化,利用形态学鉴定方法和基于rDNA-ITS与EF-1α序列分析的分子鉴定方法对分离物进行鉴定,并按照柯赫氏法则对其致病性进行测定。结果显示,经组织分离法共获得真菌菌株347株,其中230株镰刀菌属真菌菌株引起马铃薯镰刀菌根腐病,这些镰刀菌分属于5个种,分别为尖孢镰刀菌Fusarium oxysporum、茄病镰刀菌F. solani、锐顶镰刀菌F. acuminatum、木贼镰刀菌F. equiseti、接骨木镰刀菌F. sambucinum,这5种镰刀菌分别为67、29、50、39和45株,分离频率分别为29.13%、12.61%、21.73%、16.95%和19.56%;这5种镰刀菌的致病性有差异,其中接骨木镰刀菌和茄病镰刀菌的发病率分别为91.81%和99.99%,病情指数分别为69.56和82.23,均高于其它3种镰刀菌,是引起宁夏回族自治区马铃薯镰刀菌根腐病的优势病原菌。     

陕西省蔬菜根结线虫拮抗真菌的分离与初步鉴定

为了了解陕西省内的根结线虫生防资源,筛选更好的根结线虫生防菌,在陕西省9个县市采集了118份感染根结线虫的蔬菜植株根部样品,采用直接分离法从根结线虫卵、卵囊及雌成虫体上共分离到199株拮抗真菌.除43株不产孢及疑难种未鉴定外,其余分属于镰刀菌属、拟头孢霉属、芽枝霉属、拟青霉属、链格孢属、掘氏梅里霉属、单顶孢属、青霉属等22个属.其中镰刀菌属、拟头孢霉属及芽枝霉属真菌出现频率较高,约占总分离数的53%,且不同地区间拮抗真菌的种类与数量也存在较大差异.     

非致病性尖孢镰刀菌及其在生物防治中的应用

综述了尖孢镰刀菌的非致病性菌株作为尖孢镰刀菌致病菌生防因子的研究现状并对非致病性菌株的作用模式作了归纳总结,阐述了非致病性尖孢镰刀菌在生物防治中的应用价值及前景。     

拟康宁木霉T-51菌株生物学特性及其生物防治潜力

为进一步扩宽拟康宁木霉Trichoderma koningiopsis T-51菌株的生防应用范围,该研究测定T-51菌株菌丝生长、产孢和分生孢子萌发的最适温度、光照和碳氮源条件及其对灰葡萄孢Botrytis cinerea菌核的重寄生能力和对12种植物病原真菌的生防潜力。结果表明,拟康宁木霉T-51菌株在26℃下菌丝生长最快,生长速度达到2.5 cm/d,在20℃光照条件下产孢量最大,达到1.64×109个/皿,26～28℃光照条件下适宜T-51菌株分生孢子萌发;供试氮源中硫酸铵和硝酸铵适宜T-51菌株菌丝生长、产孢和分生孢子萌发,供试碳源中葡萄糖和可溶性淀粉适宜T-51菌株菌丝生长和分生孢子萌发,果糖和乳糖适宜T-51菌株产孢;T-51菌株能够重寄生灰葡萄孢菌核,当分生孢子悬浮液浓度为1×108个/mL时,重寄生效果最好;T-51菌株对核盘菌属Sclerotinia和丝核菌属Rhizoctonia植物病原真菌重寄生能力较强,对镰刀菌Fusarium spp.、暹罗刺盘孢菌Colletotrichum siamense、桃褐腐病菌Monilinia fructicola和稻瘟菌Mag...     

Prevalence and pathogenicity of spinach root pathogens of the genera Aphanomyces, Phytophthora, Fusarium, Cylindrocarpon, and Rhizoctonia in Sweden

In a 4-year disease survey in commercial spinach fields, pathogens were isolated from spinach root pieces placed on selective agar media. Aphanomyces cladogamus was the most abundant pathogen, followed by Phytophthora. cryptogea and Fusarium oxysporum. Rhizoctonia solani was found only occasionally. Other pathogens isolated were F. redolens, F. sambucinum and Cylindrocarpon destructans. P. cryptogea was the most severe pathogen, causing death of most plants, but A. cladogamus also caused severe root damage. Isolates of F. oxysporum ranged from highly pathogenic, i.e. P. oxysporum f.sp. spinaciae race 1. to moderately pathogenic and non-pathogenic, Rhizoctonia solani isolates also varied widely in their pathogenicity. Only a small number of the F. redotens and F. sambucinum isolates were pathogenic and most C. destructans isolates were weakly pathogenic. Isolation frequencies were relatively stable from year to year, but P. cryptogea was isolated more frequently in autumn than in spring. No clear relationships were found between pathogen prevalence and disease severity index of surveyed field plants, between pathogen prevalence and plant developmental stage, or between prevalence of the different pathogens isolated.     

北京地区西洋参根腐病病原鉴定及其致病性

根腐病是北京地区栽培西洋参的主要病害之一,为了明确引起该类病害的病原菌,对北京怀柔区罹病西洋参参根进行了病原菌的分离及鉴定。结合形态学以及rDNA ITS区、转录延伸因子TEF 1α区的分子序列特征,对分离菌株的鉴定结果显示,分离频率较高的11个菌株分属于茄镰孢（Fusarium solani）、尖镰孢（F.oxysporum）、三线镰孢（F. tricinctum）、多育镰孢（F. proliferatum）、毁灭柱孢（Cylindrocarpon destructans）。通过柯赫氏法则验证,F. solani和F. oxysporum是引起北京地区栽培西洋参根腐病的主要病原菌;致病性测定结果发现F. solani不同菌株的致病性及致病力表现出明显差异。     

AM真菌和根结线虫互作对黄瓜生长及生理特征的影响

通过盆栽试验研究了丛枝菌根真菌Arbuscularmycorrhiza（AM）和南方根结线虫Meloidogyneincognita互作对黄瓜幼苗生长及生理特征的影响。结果表明,预先接种地表球囊霉Glomusversi—forme再接种线虫处理的鲜、干重较只接种线虫的处理显著增加;预先接种AM真菌再接种线虫处理的根结线虫病情指数、AM真菌侵染率较只接种线虫的处理明显降低;接种线虫使黄瓜植株的过氧化物酶（POD）、过氧化氢酶（CAT）及苯丙氨酸解氨酶（PAL）、总酚含量有不同程度提高,其中预先接种根内球囊霉G．intraradices对黄瓜植株起到了较好的保护作用;与对照相比,只接种线虫处理的叶片磷含量降低了25．26％,预先接种AM真菌再接种线虫处理的叶片磷含量较只接种根结线虫的含量高。     

淡紫拟青霉对大豆胞囊线虫卵及2龄幼虫的影响

研究了淡紫拟青霉M-14、IPC菌株对大豆胞囊线虫卵孵化及2龄幼虫活性的影响。结果表明,M-14滤液及其菌丝内溶物、IPC滤液、ZnCl_2溶液等不同处理间存在极显著差异(P<0.01)。代谢产物对卵生理活性的影响因试验菌株的不同而异,M-14菌株发酵滤液及其内容物对大豆胞囊线虫卵的孵化具有强烈的抑制作用,而IPC菌株的影响则较弱。大豆胞囊线虫2龄幼虫在M-14发酵滤液原液及1倍稀释液中均表现为麻痹僵直,线虫死亡率随时间的延长而增加,72h后幼虫死亡率分别达到96.8％和90.5％。将经M-14原液处理24h的幼虫置于清水中,仅有极少数能够恢复活性,证明M-14代谢产物具有很强的杀线虫活性。     

Effect of application timing and method on efficacy and phytotoxicity of 1,3-D, chloropicrin and metam-sodium combinations in squash plasticulture

BACKGROUND: Metam-sodium, 1,3-dichloropropene (1,3-D) and chloropicrin are widely used soil fumigants. Combined application of metam-sodium and 1,3-D + chloropicrin is intended to improve efficacy and broaden spectrum of control, but little is known about the effect on crop safety. This study aimed to evaluate the effects of application timing of fumigant combinations on soilborne pest and disease control (nematodes, soil fungi and weeds) and growth of squash. Two separate tests with chisel-injected and drip-applied fumigant combinations and plant-back times ranging from 1 to 4 weeks were conducted in Tifton, GA, USA, in spring and fall 2002. RESULTS: Fumigant combinations using 1,3-D, chloropicrin and metam-sodium were as effective as methyl bromide in controlling Meloidogyne incognita (Kofoid & White) Chitwood, Pythium irregulare Buis., Rhizoctonia solani Kühn and Cyperus esculentus L. Chisel-applied combinations were more effective in terms of root-knot nematode control than drip-applied combinations. Root-knot nematode reduced squash yields by up to 60%. Phytotoxicity problems and lower yields were observed during spring, especially following 1,3-D + chloropicrin and when plant-back periods were shorter. CONCLUSION: The main problem with fumigant alternatives to methyl bromide may not be reduced efficacy but, in particular for 1,3-D products, loss of flexibility in terms of longer plant-back periods.     

施用生防菌菌剂与日光消毒和生物熏蒸相结合防治番茄根结线虫的研究

在温室条件下,研究了覆膜日光消毒、有机物料生物熏蒸和接种根结线虫拮抗菌Bacillus cereus X5对番茄生物量、根结线虫侵染以及根际土壤和土体土壤中微生物数量变化的影响。结果表明,对根结线虫滋生土壤进行覆膜日光消毒、生物熏蒸和接种拮抗菌的联合处理效果最佳,优于单一处理。联合处理的番茄生物量干重比对照增加了1.8倍;每株番茄根结线虫卵块数和每卵块的虫卵数量分别减少了190.4%和380.5%,对根结线虫的防治效果达到82.7%;根际土壤和土体土壤的细菌和真菌数量显著增加;土壤中根结线虫的数量显著减少。     

Reproduction and Development ofAphelenchoides Besseyi

The mode of reproduction of the Indian population ofAphelenchoides besseyi was studied under different temperatures and on different fungal species used for culturing the nematode. Although parthenogenetic reproduction in this species was recorded on all the fungi tested, the influence of the different fungal species on development and population buildup varied. There was a significant increase in nematode fecundity when one or two males were placed along with single females in the medium, as compared with when no male was introduced. Increasing the number of males further to eight depressed fecundity as compared with the treatment with two males.     

Pathogenicity of fungi associated with winter loss and injury in white lupin

Fungi isolated from diseased white lupin plants were tested for pathogenicity in standardized glasshouse tests to assess their potential as causes of plant death in winter in autumn-sown crops. Pleiochaeta setosa and, to a slightly lesser extent, Fusarium avenaceum caused lesions or plant death when inoculated onto hypocotyls of lupin seedlings. Disease was more severe when the hypocotyls were wounded before inoculation. F. avenaceum also caused injury when inoculated onto roots; wounding the roots had no effect. Some isolates of F. solani also caused injury, especially after root inoculation, but isolates of F. oxysporum and Cylindrocarpon destructans were only slightly or non-pathogenic. Isolates of Fusarium and C. destructans , but not of P. setosa , differed in pathogenicity. There were differences in susceptibility to disease among three lupin cultivars.     

淡紫拟青霉的培养和对南方根结线虫的防治试验

初步筛选出椰子汁及麦麸为大量繁殖淡紫拟青霉的最适培养基质。室内测定这种真菌对番茄南方根结线虫早期发育阶段卵的寄生率为54％。在室温移栽时,用4克和8克稻谷培养的菌剂处理,50天后线虫卵寄生率分别是35.3％和41.2％。蔬菜塑料大棚小区处理结果表明,移栽前一个月施用这种菌的麦麸加沙培养物,番茄植株平均高度比对照高4～5cm,花果数增加,根结根数和幼虫数量仅为对照的1/3到1/4。