浙江省柑橘绿霉病菌对嘧菌酯的敏感性研究

采用孢子萌发法和生长速率法测定了2000~2006年间采自浙江衢州、杭州、金华、丽水的65个柑橘绿霉病病菌Penicillium digitatum菌株对嘧菌酯的敏感性。结果表明:嘧菌酯对供试菌株 孢子萌发和菌丝生长的EC50值均呈单峰分布,分别介于0.020 1 ~0.260 0 μg/mL和0.005 3 ~0.079 4 μg/mL 之间,平均值分别为0.042 6 μg/mL 和0.025 0 μg/mL。敏感性频次分析结果表明,该65个菌株孢子萌发和菌丝生长对嘧菌酯的敏感性频率分布均符合正态分布,其EC50平均值0.042 6±0.030 4 μg/mL 和0.025 0±0.012 9 μg/mL可分别作为柑橘绿霉病菌孢子萌发和菌丝生长对嘧菌酯的敏感基线。     

8种杀菌剂对核桃炭疽病病原菌胶孢炭疽菌的室内毒力

由胶孢炭疽菌Colletotrichum gloeosporioides引起的核桃炭疽病是目前危害山东省核桃生产的主要病害。为筛选防治该病害的高效药剂,在确定了最适菌丝生长和分生孢子萌发温度的基础上,采用菌丝生长速率法和孢子萌发法,测定了8种常用杀菌剂对胶孢炭疽菌的毒力,评估了温度对咪鲜胺和戊唑醇毒力的影响,检测了17个胶孢炭疽菌菌株对咪鲜胺和戊唑醇的敏感性,同时评价了这2种杀菌剂的预防和治疗作用。结果显示:在胶孢炭疽菌菌丝生长和孢子萌发的最适温度28℃下,供试8种杀菌剂中,咪鲜胺、戊唑醇和三唑酮对供试菌株菌丝生长的抑制作用最强,平均EC50值分别为0.07、1.45和3.04 mg/L;异菌脲、代森锰锌和咪鲜胺对分生孢子萌发的抑制作用最强,平均EC50值分别为21.07、25.14和25.18 mg/L。咪鲜胺对菌丝生长的抑制作用受温度影响较小,而戊唑醇对菌丝生长的抑制作用随温度降低而增强;供试17个菌株对咪鲜胺和戊唑醇均有较高敏感性,平均EC50值分别为0.08 和 1.03 mg/L。建议在核桃炭疽病发病的不同时期,轮换使用咪鲜胺、戊唑醇、三唑酮、异菌脲和代森锰锌等杀菌剂,以有效控制该病害。     

新杀菌剂对番茄灰霉病菌的室内毒力及田间防效

室内采用菌丝生长速率法、孢子萌发法和黄瓜子叶法测定了咯菌腈、抑霉唑、福美双、吡唑醚菌酯和嘧霉胺对番茄灰霉病菌( Botrytis cinerea)的抑制作用。结果表明,菌丝生长速率法和孢子萌发法的测定均以咯菌腈毒力最高,EC 50分别为0.005 2 μg/mL和0.087 6 μg/mL;黄瓜子叶法测定以抑霉唑毒力最高,其EC 50为0.675 3 μg/mL。田间药效试验结果表明：50%咯菌腈可湿性粉剂90 g/ hm2对番茄灰霉病的田间防效达到90%以上,显著高于对照药剂50%啶酰菌胺水分散粒剂300 g/hm2和40%嘧霉胺悬浮剂 480 g/hm2的防效。     

Strains of Botrytis cinerea resistant to dicarboximide and benzimidazole fungicides in New Zealand vineyards

In a survey of New Zealand vineyards at harvest 1985, isolates of Botrytis cinerea resistant to benzimidazole and to dicarboximide fungicides were common. The mean frequency of resistance in the major vine-growing districts ranged from 8 to 41% for benzimidazoles, and from 51 to 59% for dicarboximides. All benzimidazole-resistant isolates showed high levels of resistance (EC50 greater than 100 mg/l carbendazim based on radial growth response), and all dicarboximide-resistant isolates showed low levels of resistance. Two subgroups of dicarboximide-resistant isolates were recognized, distinguished in the first instance by their osmotic response. Low-level resistant isolates, which formed a dense margin on osmotically amended medium, exhibited an EC50 for mycelial growth on iprodione of c. 3-2 mg/l; ultra-low-level resistant isolates, which formed a fibrillose margin on osmotically amended medium identical to that of sensitive isolates, exhibited an EC50 of c. 1-3 mg/1. In agar culture, radial growth rate, and conidial and sclerotial production of both subgroups were similar to those of sensitive isolates. Virulence (lesion size) and conidial production on grape berries were highest in sensitive isolates, intermediate in ultra-low-level dicarboximide-resistant isolates, and lowest in low-level dicarboximide-resistant isolates. Evidence is presented indicating that ultra-low-level dicarboximide-resistant strains have progressively replaced low-level dicarboximide-resistant strains in the vineyard population. The presence of dicarboximide-resistant strains was linked with a partial loss of fungicide efficacy.     

氰烯菌酯对禾谷镰孢菌分生孢子萌发及菌丝生长的影响

氰烯菌酯(2-氰基-3-氨基-3-苯基丙烯酸乙酯,JS399-19) 是一种对禾谷镰孢菌Fusarium graminearum具有专化活性的新型杀菌剂。离体条件下,采用菌丝生长速率法测定了该药剂对禾谷镰孢菌抗性菌株和敏感菌株的生长抑制活性;同时采用孢子萌发法测定了其对禾谷镰孢菌分生孢子萌发的影响。结果表明,氰烯菌酯能够强烈地抑制禾谷镰孢菌敏感菌株菌丝的生长,EC50值分布在0.092~0.141 μg/mL之间;并可降低敏感菌株分生孢子的萌发速率,以及影响其萌发的方式,使芽管从分生孢子基部和中间细胞萌发的比率增加;同时氰烯菌酯使敏感菌株分生孢子膨大、畸形,并使其芽管肿胀、扭曲,明显抑制其芽管的伸长生长;但对抗性菌株的抑制作用和致畸作用不明显。     

六种杀菌剂对烟草赤星病菌菌丝生长和分生孢子萌发的抑制作用

采用菌丝生长速率法和孢子萌发法测定了烟草赤星病菌Alternaria alternata对6种杀菌剂(氟硅唑、异菌脲、菌核净、嘧菌酯、醚菌酯及多菌灵)的敏感性。结果表明:6种杀菌剂对烟草赤星病菌菌丝生长和分生孢子萌发均表现出了不同程度的抑制活性。其中,对菌丝生长抑制活性最强的是氟硅唑,EC50平均值为(0.34±0.11)mg/L,其次为菌核净[(1.13±0.68)mg/L]和异菌脲[(2.08±0.24)mg/L];对分生孢子萌发抑制活性最强的是嘧菌酯协同100 mg/L水杨肟酸,EC50平均值为(0.28±0.09)mg/L,其次分别为单独处理的嘧菌酯[(5.79±2.76)mg/L]、醚菌酯[(11.93±3.93)mg/L]、菌核净[(19.95±15.94)mg/L]和异菌脲[(23.33±11.33)mg/L]。多菌灵对烟草赤星病菌菌丝生长和分生孢子萌发的抑制活性均最差,不宜用于烟草赤星病的防治,而异菌脲、氟硅唑、嘧菌酯和醚菌酯均有必要进一步针对烟草赤星病进行田间防效试验。     

黄瓜褐斑病防治药剂的离体活性筛选

离体条件下针对黄瓜褐斑病菌对19种杀菌剂进行了活性筛选。结果表明,不同杀菌剂对褐斑病菌菌丝生长和孢子萌发抑制作用不同。对褐斑病菌菌丝生长具有强烈抑制作用的杀菌剂为苯醚甲环唑、咪鲜胺、代森锰锌及嘧霉胺,其EC50分别4.21、4.67、5.59 μg/mL及4.11 μg/mL。甲氧基丙烯酸酯类杀菌剂及防治卵菌病害的药剂对褐斑病菌菌丝生长几乎没有影响。烯肟菌酯、福美双、代森锰锌、烯酰吗啉、百菌清和多菌灵对褐斑病菌孢子萌发具有强烈抑制作用,其EC50分别为3.34、6.62、0.28、3.54、0.53 μg/mL及0.26 μg/mL。50 μg/mL的嘧霉胺虽对孢子萌发抑制作用较小,但10 μg/mL时即可导致萌发的芽管出现明显卷曲、畸形。     

不同生育阶段黄瓜菌核病菌对几种三唑类杀菌剂的敏感性

采用菌丝生长速率法测定了6种三唑类杀菌剂和4种其他杀菌剂抑制黄瓜菌核病菌Sclerotinia sclerotiorum(Lib.)de Bary菌丝生长的毒力,同时测定了其对菌核形成及萌发的抑制作用。结果表明,甲基硫菌灵抑制菌丝生长的毒力最低,EC50值为65.75 μg/mL;己唑醇和戊唑醇的抑制活性较高, EC50值分别为0.09和0.16 μg/mL,毒力分别是甲基硫菌灵的763.7和423.4倍;其次是丙环唑、氟硅唑、腈菌唑,毒力是甲基硫菌灵的137.3~286.6倍;再次为三唑酮,毒力仅为甲 基硫菌灵的20.6倍;腐霉利、菌毒清抑制菌丝生长的毒力较低,EC50值均大于10 μg/mL。在EC50值 浓度下,所有供试药剂对菌核形成及其数量均没有影响,但三唑类杀菌剂对菌核单重影响较大,各处理所形成的菌核单重降低率均在70%以上;而当药剂浓度在10 μg/mL以下时,己唑醇等三唑类杀菌剂对菌核萌发均没有影响。     

不同杀菌剂对番石榴枝枯病病原菌的毒力和田间防效

为有效防治我国近些年新发现的番石榴枝枯病,本研究采用菌丝生长速率法和孢子萌发法,测定了8种杀菌剂对番石榴枝枯病菌(小新壳梭孢)的毒力,筛选出高效药剂,并进行田间防治试验。结果表明:30%咪鲜胺CS对小新壳梭孢的抑菌能力最强,EC_(50)为0.2 mg/L;其次是60%苯醚甲环唑WG和35%苯甲·嘧菌酯SC,EC_(50)分别为0.23和0.29 mg/L。30%咪鲜胺CS和35%苯甲·嘧菌酯SC对小新壳梭孢分生孢子萌发的抑制作用最强,EC_(50)分别为0.07和0.09 mg/L;30%咪鲜胺CS和60%苯醚甲环唑WG的预防作用和治疗作用效果也最好;田间试验结果表明,使用30%咪鲜胺CS和60%苯醚甲环唑WG防治番石榴枝枯病的防效最好,达到56.87%和52.40%,有较大的应用潜力。     

铁皮石斛黑斑病菌室内药效试验

通过供试的18种药剂对铁皮石斛黑斑病菌体外抑制作用测试结果表明,除克菌特外,所有药剂对其孢子萌发都有显著的抑制作用,其中代森锰锌、易保、代森锌和炭疽福美可完全抑制孢子萌发,霉克特、扑海英、使百克、新太生、甲基托布津和世高对孢子萌发有较强烈的抑制作用。与对照比较,克菌特促进孢子萌发率高于对照23.34%,克菌特和庄园乐都能促进芽管生长。18种药剂对石斛黑斑病菌菌丝体的抑制作用测定结果显示,所有药剂对菌丝生长都有显著的抑制作用,其中使百克和世高对菌丝体抑制效果最好,抑菌率都达91.28%,其次是施佳乐、福星和扑海英。     

7种杀菌剂对3种林木腐烂病菌的毒力测定及活性评价

林木腐烂病是苹果树、梨树和杨树等林木枝干的重要真菌性病害。为了筛选出对苹果树腐烂病菌Valsa mali var. mali、梨树腐烂病菌V. mali var. pyri和杨树腐烂病菌V. sordida等3种不同寄主腐烂病菌都能有效防控的杀菌剂,本研究开展室内毒力试验比较了7种杀菌剂对3种腐烂病病原菌菌丝生长和分生孢子萌发的抑制效果,并进一步通过田间活性测定试验比较7种杀菌剂对梨树腐烂病病斑扩展和分生孢子发生的防治效果,同时测定了增效剂8.6%聚乙二醇(PEG)对7种杀菌剂的增效作用。毒力测定结果表明,苯醚甲环唑、戊唑醇、吡唑醚菌酯和丙唑·多菌灵对3种腐烂病病原菌菌丝生长和分生孢子萌发的抑制作用较强,其中EC50平均值最低的是苯醚甲环唑,而戊唑醇的MIC平均值最低,在0.33 mg/L浓度下对3种腐烂病病原菌的菌丝生长和分生孢子萌发抑制率均达到100%。田间试验结果表明,45%苯醚甲环唑SC、43%戊唑醇SC和35%丙唑·多菌灵SE对梨树腐烂病病斑扩展和分生孢子萌发的防治效果突出,其中45%苯醚甲环唑SC 30.00 mg/L对病斑扩展防治效果达到82.23%,孢子萌发抑制效果达到85.96%,田间防治效果最好。10%丙硫唑SC+8.6% PEG处理组对病斑扩展防治效果提高了15.39百分点,达到73.46%,分生孢子萌发抑制率提高了23.75百分点,达到83.06%,增效作用显著。本研究为苹果树、梨树和杨树等3种寄主腐烂病的化学防控提供了科学依据。     

爵床提取物对辣椒炭疽病菌的抑制作用及其苗期防效

爵床(J usticia procumbens L.)是一种传统的中药材.为探明爵床提取物对辣椒炭疽病菌的抑制作用,采用生长速率法和孢子萌发法分别测定了爵床提取物对辣椒炭疽病菌菌丝生长、孢子产生和孢子萌发的抑制作用,采用苗期盆栽试验观察爵床提取物对辣椒炭疽病的防治效果.结果表明,爵床甲醇提取物可抑制辣椒炭疽病菌菌丝生长、孢子产生和孢子萌发,其活性随着浓度的提高而增强,抑制中浓度分别为4.23、2.16和2.98 mg/mL.通过对爵床提取物处理后病菌孢子萌发形态显微观察,发现病菌孢子芽管长度受到明显抑制甚至不能萌发.当提取物浓度为16mg/mL时对苗期辣椒炭疽病的防效达73.08％.     

4种戊烷脒同系物对灰霉病的防治效果

采用载玻片萌发法、抑制菌丝生长速率法、组织测定法，结合田间小区试验，系统研究了戊烷脒及其同系物乙烷脒、丙烷脒、丁烷脒对番茄灰霉病菌的抑制活性和田间防治效果。结果表明，各化舍物对灰霉病均有一定的抑制活性，其中丙烷脒和丁烷脒对灰霉病的抑制活性较高，二者抑制菌丝生长的EC50分别为0．6821mg／L和2．1599mg／L，抑制孢子萌发的EC50分别为2．7510mg／L和5．7362mg／L；丙烷脒和丁烷脒对番茄灰霉病有较高的保护和治疗作用；在田问试验条件下，连续2次施药后，以120g ai／hm^2施用剂量防治豇豆灰霉病，丙烷脒和丁烷脒的防治效果分别为78．03％和54．52％，以100gai／hm^2施用剂量防治草莓灰霉病，防治效果分别为71．97％和68．96％，均优于对照药剂施佳乐（450gai／hm^2）和速克灵（468．8gai／hm^2）。丙烷脒和丁烷脒具有开发成为农用杀菌荆的潜力。     

石榴皮萃取物对番茄灰霉病菌抑制作用及防病效果

试验测定了石榴皮萃取物对番茄灰霉病菌室内抑菌作用和对番茄灰霉病的温室盆栽防治作用。室内抑菌试验分别采用生长速率法和孢子萌发法测定对番茄灰霉病菌菌丝生长和孢子萌发的抑制作用,结果表明：正丁醇萃取物对病原菌菌丝的抑制活性最高,EC50为50.28 g/L;浓度为200 g/L对番茄灰霉病菌分生孢子的产生具有显著的抑制作用,抑制作用与浓度呈正相关关系。在温室盆栽试验中, 正丁醇萃取物稀释100倍的处理对番茄灰霉病的保护防治效果达到46.41%,治疗防治效果达到48.00%。     

多菌灵等4种杀菌剂对烟草灰霉病菌的室内生物活性

采用菌丝生长速率法和孢子萌发法,分别测定了烟草灰霉病菌对多菌灵、嘧霉胺、异菌脲和丙环唑的敏感性,同时通过离体叶片法评估了这4种杀菌剂对烟草灰霉病的保护和治疗作用。结果表明:4种杀菌剂对烟草灰霉病菌的菌丝生长和孢子萌发均表现出了不同程度的抑制活性,并对灰霉病同时具有保护和治疗作用。其中多菌灵对菌丝生长的抑制活性最强,EC₅₀平均值为0.06 mg/L,其次为丙环唑、嘧霉胺和异菌脲,EC₅₀平均值分别为0.36、0.53和0.60 mg/L;异菌脲和丙环唑对烟草灰霉病菌孢子萌发的抑制活性较强,EC₅₀平均值分别为2.05和2.21 mg/L,其次为嘧霉胺和多菌灵,EC₅₀平均值分别为10.56和131.23 mg/L。异菌脲和多菌灵对灰霉病的保护作用和治疗作用均最强,当药剂质量浓度为200 mg/L时,其对离体叶片的保护和治疗作用防效分别为100%、100%和98.3%、91.8%。研究结果可为烟草灰霉病的科学防治提供依据。     

香蕉弯孢霉叶斑病菌生物学特性及对杀菌剂敏感性研究

香蕉弯孢霉叶斑病菌［Curvularia lunata (Wakker) Boed］适合生长的培养基有PSA、PDA和OMA;菌落生长、产孢和孢子萌发最适宜的温度为25～30 ℃,pH要求不严格为5～9;在碳源和氮源中,蔗糖、葡萄糖、尿素、磷酸氢二氨和硝酸钠有利于病菌生长和产孢;分生孢子萌发对湿度有严格的要求,RH≥80%以上分生孢子萌发,随湿度增加萌发率增高;光照对菌丝体无显著影响,光暗交替有利于孢子的形成; 孢子致死温度为55 ℃(10 min)。药物敏感性测定结果表明,6%戊唑醇微乳剂、25%丙环唑乳油、25%咪鲜胺水乳剂、25%戊唑醇乳油和25%苯醚甲环唑乳油对香蕉弯孢霉叶斑病菌菌丝生长均有较好的抑制效果,其中25%咪鲜胺水乳剂和25%苯醚甲环唑乳油的抑菌效果最好。     

韭菜灰霉病防治烟剂的筛选与评价

为筛选适合制备安全、高效防治韭菜上灰霉病烟剂的杀菌剂品种,从原药抑菌活性、烟雾毒力作用、成烟率、安全性和田间防效5个方面,对9种常用杀菌剂制备成韭菜灰霉病防治烟剂的可行性进行了评价.室内毒力测定结果表明:氟啶胺、咯菌腈和啶菌噁唑抑制韭菜灰霉病菌菌丝生长的EC50值分别为0.13、0.05和0.12 mg/L;吡唑萘菌胺...     

杀菌剂对辣椒疫霉不同形态菌体的毒力差异

室内离体条件下测定了9种杀菌剂对辣椒疫霉各生长阶段的抑制作用。结果表明:烯酰吗啉和氟吗啉对所测定的菌株P1319 4个发育阶段均有显著的抑制作用,EC50值分别为0.14~0.61 μg/mL 和0.18~0.68 μg/mL,EC95值均小于3 μg/mL;甲霜灵对菌丝生长和孢子囊形成有显著的抑制作用,但对休止孢和孢子囊萌发基本无影响;嘧菌酯和百菌清强烈抑制孢子囊形成、休止孢和孢子囊萌发,EC50值分别为0.03~6.15 μg/mL和0.07~1.97 μg/mL;较高浓度的代森锰锌可以抑制辣椒疫霉的孢子囊形成、休止孢萌发和孢子囊直接萌发,但对菌丝生长无抑制作用;三乙膦酸铝、p(ο)-丁酰基苯酚和邻-烯丙基苯酚对P1319的4个发育阶段的抑制作用较弱。     

Effects of fungicides on in vitro spore germination and mycelial growth of the phytopathogens Leptosphaeria maculans and L. biglobosa (phoma stem canker of oilseed rape)

BACKGROUND: Phoma stem canker, caused by the coexisting related fungal pathogens Leptosphaeria maculans (Des.) Ces. & de Not and L. biglobosa Shoemaker & H Brun, is a major disease of winter oilseed rape in the UK. Annually, over 90% of UK crops receive at least one foliar application of fungicide, but little is known about the sensitivity of the more damaging L. maculans and the less damaging L. biglobosa to these fungicides. The effects of flusilazole, tebuconazole and Methyl Benzimidazole Carbamate (MBC) fungicides (benomyl and carbendazim) on the germination of ascospores, conidia and germ tube growth of both species were examined. Isolates collected from different oilseed rape crops in England and Wales were assessed for their mycelial growth on fungicide‐amended medium, and ED₅₀ values were calculated. RESULTS: Leptosphaeria maculans and L. biglobosa differed in their sensitivity to fungicides. Conidial germination of L. maculans was more sensitive to these fungicides than that of L. biglobosa. Isolates of L. maculans had smaller ED₅₀ values for mycelial growth for all fungicides tested than isolates of L. biglobosa. CONCLUSION: These results suggest that fungicide applications might affect the structure of L. maculans/L. biglobosa populations in UK winter oilseed rape crops. Copyright © 2009 Society of Chemical Industry     

A rapid and simple method for determining fungicide resistance in Botrytis

A simple test based on the germination of conidia of Botrytis on agar media augmented with various fungicides has been developed. Average concentrations causing a 50% reduction of germ-tube growth (EC₅₀) of highly sensitive isolates were determined on 1% malt extract agar (thiophanate-methyl 0.090 ppm; iprodione 0.566 ppm; fludioxonil 0.026 ppm; fenhexamid 0.144 ppm), 1% malt extract agar with 100 ppm salicyl hydroxamic acid (QoI fungicides, viz. trifloxystrobin 0.009 ppm; pyraclostrobin 0.013 ppm; azoxystrobin 0.087 ppm), 0.5% yeast extract agar (boscalid 0.069 ppm) and 0.5% sucrose agar (cyprodinil 0.053 ppm). In order to detect different levels of resistance against these various fungicides, two discriminatory concentrations were identified for each compound. A routine assay method was developed in which drops of a conidial suspension harvested directly from diseased plant material or sporulating cultures were incubated on each of 20 different agar media. Because of a very short time-span of 24–48 h between sample collection and evaluation of results, field-specific information on the occurrence, frequency and types of resistance of Botrytis against common botryticides in soft-fruit production may be generated prior to the main fungicide spray season at blossom time.