不同杀菌剂及混剂对番茄灰霉病菌的室内抑制效果研究

[目的]筛选高效、低毒的番茄灰霉病杀菌剂,缓解和治理其抗药性.[方法]在室内离体条件下,采用生长速率法及抑制孢子萌发法测定了几种杀菌剂对番茄灰霉病菌的敏感性.[结果]30;爱苗、50;福美双、40;施灰乐、50;扑海因,对病原菌菌丝生长的EC_(50)值在0.347 6～0.724 2 μg/mL,均小于1 μg/mL,番茄灰霉病菌对上述杀菌剂均处于比较敏感的阶段;50;农利灵和65;乙霉威的EC_(50)均大于1 μg/mL,敏感程度相对较低.孢子萌发试验中,30;爱苗、50;福美双、50;扑海因对番茄灰霉菌孢子萌发的抑制活性高,EC_(50)值在1.308 5～1.336 4 μg/mL;50;农利灵和40;施灰乐的抑制活性次之,EC_(50)分别为1.525 4和1.777 4 μg/mL;65;乙霉威的抑制活性相对较低,EC_(50)为2.173 8 μg/mL.[结论]将不同作用机理的杀菌剂50;扑海因与50;福美双以1∶1和1∶2的比例混配,联合毒力测定和评价结果表明相互作用为增效.     

打瓜白粉病的发生及化学药剂防治试验

打瓜白粉病是打瓜上最严重病害之一,给生产带来了严重影响.探讨白粉病的发生特点、防治具有很重要的意义.2008年通过调查得出,福海县打瓜白粉病的发病初期为7月初,气候条件适宜时,7月底8月初瘸害达到高峰值,发病率可达100;,发生面积广,危害程度重.2007年通过药剂筛选试验,筛选出防治效果较好的药剂为福星、敌力康,防治效果达77.02;、73.90;.因此,控制好打瓜白粉病的严重危害,必须抓住防治关键时期,于病害发生前期,即6月底7月初进行喷药预防,以后每隔7～10 d喷药防治一次,喷3～6次,可以取得好的防治效果.     

几种新杀菌剂对柑桔炭疽病的防治效果

炭疽病是危害柑桔的重要病害之一,造成柑桔树落花落果,树势衰退,减产甚至失收,药剂防治仍然是目前最有效的防治方法之一.2007年秋季进行了几种新杀菌剂防治柑桔炭疽病的田间试验,结果表明:20%苯醚甲环唑水乳剂、25%凯润乳油、70%品润干悬浮剂等药剂对炭疽病有良好的防治效果,施药3次后的防治效果分别达到80.07%,78.78%和76.47%,是防治柑桔炭疽病的优良药剂,建议进一步在柑桔产区示范和推广应用.     

六种杀菌剂对向日葵白锈病的田间防治效果

六种药剂对向日葵白锈病的田间防效试验结果表明:25;甲霜灵WP 1 000倍液、50;安克WG 2 500倍液的防效较高,分别为87.6;和86.8;;显著优于防效次之的64;杀毒矾WP 800倍液(防效75.7;)和其他3种杀菌剂.52.5;抑快净WG 1 000倍、72;霜疫必克WP 600倍和80;乙磷铝WP 600倍的防效相当,均未达到50;,是供试药剂中防效较低的3种杀菌剂.经方差分析三者间差异显著.     

防治烤烟棒孢霉叶斑病药剂试验

采用9种药剂防治烤烟棒孢霉叶斑病的盆钵烟株及田间小区药效试验,结果表明:代森锰锌对烤烟棒孢霉叶斑病的防治效果较好,防效的校正值(下同)达83.8%,在喷药后经历连续雨天的情况下,病指迅速下降并保持较为平稳的低病指,是可用于大田生产的农药;多菌灵的防效虽然较好,达84.3%,但其含有硫磺粉,不宜在烤烟采烤期使用;扑菌特与百菌清的防效分别为81.6%和68.5%;甲基托布津的防效较差,仅为31.2%.代森锰锌可作为烤烟大田发生棒孢霉叶斑病的防治药剂.     

PS04菌株的抗真菌活性

前一阶段分离得到1株具有抗真菌活性的细菌菌株PS04,室内测定结果表明,该菌株培养物乙醇抽提物对水稻纹枯病、稻瘟病等多种植物病害的病原真菌具有抗菌活性,对水稻纹枯病病原的抑制中浓度为99.4μg/mL,作用于植物病原真菌,导致菌丝畸形,菌丝体节间缩短,菌丝体顶端分枝增多。该抑菌活性物质稳定性好,在温度40~100℃,pH6.2~7.0范围内稳定。     

Sensitivity of Uncinula necator to quinoxyfen: evaluation of isolates selected using a discriminatory dose screen

Quinoxyfen is a protectant fungicide that provides excellent control of many powdery mildew diseases. Prior to the launch of quinoxyfen in vines in 1998, a leaf disc sporulation assay was developed to assess the sensitivity of Uncinula necator (Schw) Burr to quinoxyfen. The distribution of EC(50) values from 56 monoconidial U. necator isolates collected from six countries between 1993 and 1996 was found to range from less than 0.03 to 2.6 mg litre(-1). Although this range of EC(50) values was quite broad, the inability to establish a minimum inhibitory concentration (MIC) for the majority of these isolates, including some of the most sensitive isolates, was unexpected and suggested that the leaf disc sporulation assay may not reflect the true activity of quinoxyfen in the field. In 2002, following the detection of isolates resistant to quinoxyfen in Blumeria graminis Speer f. sp. tritici Marchal, a discriminatory dose screen was developed to test large populations of U. necator for rare individuals with significantly decreased sensitivity to quinoxyfen. The individual isolates selected by this method were tested with the leaf disc sporulation assay. Although a significant proportion were found to have EC(50) values within the original distribution, a number of isolates with apparent reduced sensitivity to quinoxyfen were also detected. However, further examination of a subset of these isolates in a more quantitative germination/germ tube elongation inhibition assay suggested that the magnitude of the reduction in sensitivity for some of these isolates was much less than predicted by the sporulation assay. Thus, for an exclusively protectant fungicide such as quinoxyfen, a leaf disc sporulation assay may overestimate the frequency of isolates with significantly reduced sensitivity and the threat of decreased performance due to resistance.     

Efficacy of methyl iodide and synergy with chloropicrin for control of fungi

Efficacy of soil fumigation with methyl bromide and methyl iodide against Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum, Gliocladium virens, Phytophthora citricola, Phytophthora citrophthora, Pythium ultimum, Rhizoctonia solani and Verticillium dahliae was determined in laboratory experiments in closed fumigation chambers. Pythium ultimum was the most sensitive fungal species with EC₅₀ values for methyl bromide and methyl iodide of 15.5 and 8.6 µM , respectively. R solani was the least sensitive with EC₅₀ values of 253.4 and 161.4 µM for methyl bromide and methyl iodide, respectively. Relative potency ([methyl bromide]/[methyl iodide]) values ranged from 5.2 for P citricola to 1.5 for F oxysporum. Methyl iodide was 2.7 more efficacious than methyl bromide averaged over all fungal species. Methyl bromide/chloropicrin and methyl iodide/chloropicrin applied jointly were 2.2 and 2.8 times more efficacious, respectively, against F oxysporum than when the compounds were applied singly. Combining methyl bromide and methyl iodide with chloropicrin resulted in a significant synergistic increase in activity against F oxysporum. © 2000 Society of Chemical Industry     

北方五省(区)马铃薯晚疫病菌对甲霜灵和精甲霜灵的敏感性检测

为了明确我国不同地区马铃薯晚疫病菌对甲霜灵和精甲霜灵的抗性状况,2007-2009年从河北、黑龙江、吉林、辽宁和内蒙古马铃薯主产区采集马铃薯晚疫病菌,采用菌丝生长速率法和叶盘漂浮法测定其对甲霜灵的敏感性,采用叶盘漂浮法测定其对精甲霜灵的敏感性.结果表明:以菌丝生长速率法检测的380株晚疫病菌中和以叶盘漂浮法检测的222株晚疫病菌中对甲霜灵的抗性菌株分别占80％和73.5％;菌丝生长速率法检测结果显示,河北省对甲霜灵的抗性菌株所占频率从2007年的100％降为2008年的66.4％,2009年又回升至74.2％,而吉林和黑龙江两省对甲霜灵的抗性菌株分布频率呈上升趋势.叶盘漂浮法检测的95个菌株中对精甲霜灵的抗性菌株占54.5％,其中河北省40个菌株对精甲霜灵的中间型菌株占优势(62.5％),抗性菌株仅占34.9％,而其他4省55个菌株对精甲霜灵的抗性菌株占优势(69.1％).受检测的北方五省(区)马铃薯晚疫病菌群体中对甲霜灵和精甲霜灵的抗性菌株已占优势,马铃薯晚疫病菌已普遍对甲霜灵及精甲霜灵产生抗性.在对甲霜灵和精甲霜灵普遍产生抗性的地区,应优先选用与甲霜灵、精甲霜灵作用机理不同的药剂防治马铃薯晚疫病.     

江西槟榔芋疫病病原菌鉴定及室内药剂筛选

为明确江西省九江市槟榔芋疫病的病原菌并有针对性地对该病害进行防治,本研究采集具有典型芋疫病症状的芋叶片和叶柄对病原菌进行分离纯化,结合形态学观察、致病性测定及基于ITS、Ypt1和β-tubulin基因联合系统发育分析对该病原菌进行鉴定,并测定了其对7种杀菌剂的敏感性。根据病原菌菌落、卵孢子形态等特征初步鉴定为芋疫霉Phytophthora colocasiae,基于多基因联合系统发育分析结果与形态学结果一致,确定该病原菌为芋疫霉。室内药剂筛选结果表明,23.4%双炔酰菌胺SC对菌丝生长抑制效果最好,EC₅₀为0.006μg/mL;96.8%烯酰吗啉TC、0.3%丁子香酚SL、20%氟吗啉WP、500 g/L氟啶胺SC、97%霜脲氰TC对菌丝生长的抑制效果也较好,EC₅₀介于0.094～1.272μg/mL之间,研究结果可为槟榔芋疫病的化学防治提供参考。