防治小麦纹枯病和根腐病高效药剂的筛选及其与香菇多糖联用的防效评价

为实现对小麦纹枯病和根腐病节药防控,采用菌落直径法筛选了对小麦纹枯病菌和根腐病菌高效的杀菌剂,并将其与香菇多糖联用,通过小麦拌种处理,在盆栽条件下评价其对小麦纹枯病与根腐病的防治效果。结果表明,95%己唑醇对小麦纹枯病菌、根腐病菌的毒力最高,对这两种病原菌的EC₅₀分别为0.094、0.144 mg·L^-1;97%咯菌腈对小麦纹枯病菌、根腐病菌的EC₅₀值分别为0.312、0.766 mg·L^-1。剂量为1 g a.i.·100 kg^-1小麦种子的己唑醇施药后7 d对小麦纹枯病和根腐病的防效分别为77.5%和80.2%;剂量为4 g a.i.·100 kg^-1小麦种子的咯菌腈施药后7 d对小麦纹枯病和根腐病的防效分别为75.8%和82.5%。香菇多糖与己唑醇和咯菌腈混合拌种对两种小麦病害的防效均高于单剂处理,0.5 g a.i.·100 kg^-1小麦种子的己唑醇与4 g a.i.·100 kg^-1小麦种子的香菇多糖联用7 d后,对小麦纹枯病和根腐病的防效分别为75.2%和79.4%。2 g a.i.·100 kg^-1小麦种子的咯菌腈与4 g a.i.·100 kg^-1小麦种子的香菇多糖联用与己唑醇/香菇多糖联用防效相近。综上所述,己唑醇或咯菌腈与香菇多糖联合施用,可兼治小麦纹枯病和根腐病,有助于小麦生产节药控害,降低环境污染。     

几种生物制剂对小麦根腐病菌的毒力

为探索生物制剂对小麦根腐病的防控效果,采用菌丝生长法测定了6种生物制剂对禾谷镰刀菌、刺腐霉菌和小麦离蠕孢菌的毒力。结果表明,申嗪霉素、乙蒜素和春雷霉素具有良好的抑菌效果,其中申嗪霉素的毒力最强,对禾谷镰刀菌、刺腐霉菌和小麦离蠕孢菌的EC₅₀值分别为0.350 2 mg·L^-1、0.864 5 mg·L^-1和0.134 1 mg·L^-1,乙蒜素对刺腐霉菌和小麦离蠕孢菌的EC₅₀值分别为2.957 3 mg·L^-1和2.342 7 mg·L^-1,春雷霉素对刺腐霉菌和禾谷镰刀菌的EC₅₀值分别为0.864 5 mg·L^-1和5.090 9 mg·L^-1。室内盆栽试验表明,申嗪霉素和乙蒜素对禾谷镰刀菌的防治效果显著优于春雷霉素,防治效果分别为75.73%和74.68%;乙蒜素对刺腐霉菌的防治效果最好,防效为86.28%;申嗪霉素和乙蒜素对离蠕孢菌的防效分别为87.68%和83.25%。综上所述,申嗪霉素和乙蒜素能有效抑制禾谷镰刀菌、刺腐霉菌和小麦离蠕孢菌三种病原菌的生长,对小麦根腐病防治具有很大应用潜力。     

几种杀菌剂对玉米顶腐病病原菌的毒力测定及防治效果研究

亚粘团镰孢霉引起的玉米顶腐病是我国玉米生产上的一种新病害。在室内采用菌丝生长速率法测定8种杀菌剂对亚粘团镰孢霉的抑菌效果。结果表明,25 g/L咯菌腈悬浮种衣剂的EC₅₀最小,病原菌对其敏感性最高,抑菌效果最好;60 g/L戊唑醇悬浮种衣剂和80%多菌灵可湿性粉剂的EC₅₀较小,病菌对其敏感性也较高,抑菌效果也较好;97%烯酰吗啉可湿性粉剂的EC₅₀ 最大,病菌对其敏感性最低,抑菌效果最差。通过温室种子包衣效果,生产上可使用25 g/L咯菌腈悬浮种衣剂和60 g/L戊唑醇悬浮种衣剂来防治玉米顶腐病。同时通过室内毒素平皿培养进一步明确了经咯菌腈、戊唑醇和多菌灵对玉米种子包衣处理后,不同浓度的亚粘团镰孢霉毒素滤液对玉米胚根和胚芽生长的影响。     

小麦纹枯病菌对九种麦田除草剂的敏感性

为了明确麦田除草剂对小麦纹枯病发生的影响,采用菌丝生长速率法测定了小麦纹枯病菌对九种麦田除草剂的敏感性。结果表明,酰胺类除草剂对小麦纹枯病菌毒力较强,异丙甲草胺、乙草胺、丁草胺的毒力（EC₅₀）分别为56.0、83.5和142 mg·L^-1,病菌在含药培养基上易出现轮纹状菌落;二硝基苯胺类和芳氧苯氧基丙酸酯类除草剂对纹枯病菌毒力较弱,在1 000 mg·L^-1时抑制率尚达不到50%,前者易使菌落发生扇形突变,且菌丝稀疏,后者对菌落形态无显著影响。     

噻呋酰胺对河南省小麦纹枯病菌的抑制活性

为明确噻呋酰胺对河南省小麦纹枯病菌的抑制活性,采用菌丝生长速率法测定了噻呋酰胺对2016年从河南省15个地市分离的98株病菌的毒力。结果表明,供试菌株对噻呋酰胺的EC_(50)值分布于0.009～0.405μg·mL~(-1),小麦纹枯病菌群体中存在对噻呋酰胺敏感性较低的亚群体,将其中呈连续单峰频次正态分布的大多数菌株的平均EC_(50)值(0.043±0.019μg·mL~(-1))作为病菌对噻呋酰胺的敏感性基线;方差分析及聚类分析显示,同一地市内的菌株对噻呋酰胺的敏感性(即EC_(50)值)差异较大,EC_(50)最大值和最小值之比为1.78～34.89,而不同地市的菌株对噻呋酰胺的敏感性差异不明显,噻呋酰胺EC_(50)平均值为0.035～0.155μg·mL~(-1),EC_(50)最大值是最小值的4.41倍,病菌对噻呋酰胺的敏感性与菌株的地理来源无明显相关性;噻呋酰胺对病菌的毒力与苯醚甲环唑、戊唑醇、井冈霉素及甲基立枯磷的毒力间无明显相关性。综上所述,河南省大部分小麦纹枯病菌菌株对噻呋酰胺较为敏感,可将其作为综合防控的备选药剂;生产中可将噻呋酰胺与苯醚甲环唑、戊唑醇、甲基立枯磷、井冈霉素4种药剂轮换或交替使用,以延长其使用寿命。     

小麦白粉病菌对嘧菌酯和三唑酮的敏感性反应

为了解小麦白粉病菌对嘧菌酯和三唑酮的敏感性差异,采用与田间实际用药条件相似的离体叶段喷雾法比较了2014年河南、河北麦区的小麦白粉病菌对嘧菌酯和三唑酮的敏感性。结果表明,供试菌株对三唑酮的EC₅₀为53.93 mg·L^-1,抗性水平为15.14,抗性频率高达93.57%;对嘧菌酯的EC₅₀为0.235 mg·L^-1,抗性水平为0.539,未发现嘧菌酯抗性菌株。嘧菌酯对三唑酮敏感菌和抗药菌的毒力分别是三唑酮的59倍和1 396倍。嘧菌酯与三唑酮之间无交互抗性,可见嘧菌酯具有防治小麦白粉病的应用前景。     

纳米ZnO-Ag复合材料对小麦根腐病菌侵染下小麦幼苗生长的影响

为探讨纳米杀菌剂对小麦根腐病害的防控效果,以小麦京东8号为供试材料,通过盆栽试验,探究土壤接种麦根腐平脐孺孢（Bipolaris sorokiniana）情况下,自制纳米ZnO-Ag复合材料对B.sorokiniana的抑菌效果和小麦幼苗生长的影响。结果表明,纳米ZnO-Ag复合材料能显著抑制小麦根腐菌菌丝的生长,抑制作用随ZnO-Ag浓度的增加而增强;200 μg·mL^-1ZnO-Ag对病菌菌丝的抑制率高达91.17%,有效中浓度（EC₅₀）为34.15 μg·mL^-1;在土壤接菌情况下,经大于12.5 μg·g^-1ZnO-Ag复合材料处理,小麦种子的发芽势和发芽率、幼苗的根长、株高、地上部鲜重和干重、地下部鲜重和干重均显著高于对照组（未加纳米材料）,小麦幼苗发病率显著低于对照组;浓度大于12.5 μg·g^-1ZnO-Ag处理组的小麦幼苗根长/株高和根冠比显著低于对照组。由此可得,纳米ZnO-Ag复合材料能够有效抑制土壤中小麦根腐病菌的生长,促进小麦种子萌发和幼苗生长,降低幼苗发病率。此结果为ZnO-Ag防控小麦根腐害提供了理论依据。     

2019年浙江省部分地区小麦赤霉病菌种群组成及其对杀菌剂的敏感性调查

为了解2019年浙江省小麦赤霉病菌的种群组成及其对杀菌剂的敏感性,调查了浙江省3个地区（杭州市萧山区、杭州市桐庐县、宁波市象山县）麦田的稻桩带菌率和小麦病穗率,利用PCR和DNA测序技术鉴定病菌的种群组成。结果显示,3月份3个地区田间稻桩的赤霉病菌子囊壳携带率为26.4%～55.4%,其释放的子囊孢子能正常萌发长出菌丝并快速形成菌落;小麦田间3月份空气中赤霉病菌游动孢子数量最多,4-5月份数量有所下降;田间小麦于4月份中旬开始出现病穗,4月下旬病穗率快速攀升;从386个分离菌株中随机选择的32个菌株均被鉴定为亚洲镰孢菌(Fusarium asiaticum);72个菌株被认定为多菌灵（10 mg·L_-1）抗性菌株,约占分离菌株的18.65%。采用菌丝生长速率法检测16个分离菌株对杀菌药剂的敏感性,发现75%肟菌·戊唑醇水分散粒剂和30%唑醚·戊唑醇悬浮剂对分离菌株的EC₅₀值（有效抑制中浓度）均低于5.0 mg·L_-1,40%戊唑·咪鲜胺微乳剂和25%氰烯菌酯悬浮剂对分离菌株的EC₅₀值均低于2.0 μL·L_-1,表明上述4种药剂的抑菌效果均良好;进一步对这4种杀菌药剂进行两两混配,检测对16个分离菌株的抑菌效果,发现混配方案“75%肟菌·戊唑醇水分散粒剂”+“30%唑醚·戊唑醇悬浮剂”对分离菌株的抑菌效果最强。     

噻呋酰胺种衣剂防治小麦纹枯病效果及安全性研究

为探讨噻呋酰胺应用于小麦种衣剂的可行性,测定了噻呋酰胺对小麦纹枯病的防效及对种子的安全性。结果表明,噻呋酰胺对小麦纹枯病有很好的毒力,EC₅₀为0.075 mg·L^-1; 噻呋酰胺FS以不同比例包衣后能够显著提高种子发芽势及发芽率;噻呋酰胺包衣能够显著提高小麦出苗率和植株鲜重,对根长及茎长的影响不显著; 1∶200和1∶400包衣对拔节期小麦纹枯病的防效分别为90.32%和87.79%,显著高于同等剂量下对照药剂防效。说明噻呋酰胺作为小麦种衣剂应用于纹枯病的防治是安全高效的。     

不同杀菌剂在麦穗中的消解动态及对小麦赤霉病防效评估

为探明不同杀菌剂对小麦赤霉病及籽粒DON的防效,分别检测6种杀菌剂对亚洲镰刀菌（F.asiaticum）的室内毒力,采用超高效液相色谱－串联质谱法（UPLC-MS/MS）分别检测、分析了6种杀菌剂施药1次和2次在麦穗中的消解动态及其对小麦赤霉病和籽粒DON的防效。结果表明,6种杀菌剂对亚洲镰刀菌菌丝生长抑制度表现为咪鲜胺>戊唑醇>氰烯菌酯>氟唑菌酰羟胺>吡唑醚菌酯>嘧菌酯。6种杀菌剂在麦穗中消解动态均符合一级动力学方程,50%咪鲜胺WP、430 g·L^-1戊唑醇SC、25%氰烯菌酯SC、200 g·L^-1氟唑菌酰羟胺SC、250 g·L^-1吡唑醚菌酯EC和250 g·L^-1嘧菌酯SC施药1次消解半衰期分别为2.081 5、3.094 4、2.365 7、3.026 8、3.209 0和3.136 4 d,施药2次消解半衰期分别为2.044 7、3.332 4、2.529 7、3.397 8、3.300 7和3.179 6 d。200 g·L^-1氟唑菌酰羟胺SC施药1次和2次病指防效分别为85.96%和94.88%,DON防效分别为81.43%和88.91%。430 g·L^-1戊唑醇SC、25%氰烯菌酯SC和50%咪鲜胺WP施药1次和2次病指防效分别为61.48%~73.62%和75.33%~86.15%,DON防效分别为53.88%~69.70%和60.09%~79.45%。250 g·L^-1吡唑醚菌酯EC和250 g·L^-1嘧菌酯SC施药1次病指防效分别为63.76%和50.47%,DON防效分别为41.03%和-28.95%;施药2次病指防效分别为79.51%和61.10%,DON防效分别为52.75%和-18.08%。综上所述,氟唑菌酰羟胺对赤霉病和籽粒DON防效最佳,而吡唑醚菌酯和嘧菌酯对小麦赤霉病和籽粒DON防效不突出,甚至增加毒素污染。     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

先玉335、郑单958和京科968抗虫能力的比较研究

以先玉335、郑单958、京科968为材料,以玉米螟(Ostrinia furnacalis)、黏虫(Mythimna separata)和禾谷缢管蚜(Rhopalosiphum padi)为供试昆虫,探究玉米品系大喇叭口期对玉米螟和黏虫及抽雄期对禾谷缢管蚜抗性差异,测定其主要抗虫化合物丁布类物质的含量。结果发现,京科968对玉米螟及禾谷缢管蚜抗性均高于另外两个品系;对黏虫的抗性,郑单958和京科968高于先玉335。大喇叭口期京科968中丁布类物质含量最高,抽雄期郑单958和京科968中主要丁布成分含量均高于先玉335,上述组织中丁布合成相关基因在郑单958及京科968中的表达量也均高于先玉335。本研究揭示杂交玉米抗虫性与抗性相关化合物含量及其相关基因表达间存在正向相关关系,为抗虫玉米分子育种提供理论参考。     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

Evaluation of fungicides to control Petri disease pathogens in the grapevine propagation process

The efficacy of fourteen selected fungicides against Phaeomoniella chlamydospora and Phaeoacremonium aleophilum was evaluated in vitro by mycelial growth and conidial germination assays. Azoxystrobin, carbendazim and tebuconazole were the most effective fungicides against P. chlamydospora, while carbendazim and didecyldimethylammonium chloride were the most effective against P. aleophilum. An assay was also conducted with cubiet, hydroxyquinoline sulphate and didecyldimethylammonium chloride to determine their potential to prevent infections caused by these pathogens during the hydration stage in grapevine propagation. The results of this experiment demonstrated that P. chlamydospora and P. aleophilum were able to infect healthy cuttings during the hydration stage and showed that didecyldimethylammonium chloride was consistently the best treatment as a disinfectant soak for grapevine cuttings. Additionally, semi-commercial trials were conducted in two grapevine nurseries to evaluate the effectiveness of several strategies with carbendazim, flusilazole and hydroxyquinoline sulphate at different nursery stages. Soaking planting material in carbendazim during the hydration stage was the most effective treatment since neither P. chlamydospora nor P. aleophilum were isolated from planting material in either nursery.     

Screening for resistance to early blight (Alternaria solani) in potato (Solanum tuberosum L.) using toxic metabolites produced by the fungus

Summary The phytotoxic components of the culture filtrate of the fungusAlternaria solani Sor, which causes early blight in potato, were used in this study to differentiate between resistant and susceptible genotypes selected to represent a range of reactions when screened in the field. Detached leaflet assays, using spores and toxic metabolites from the culture filtrate, were compared with field ratings and a whole-plant glasshouse test. Rank correlations between several detached leaflet tests were highly significant (P<0.01) but the correlations between these tests and the glasshouse and field tests were poor. The disease ratings obtained in the various tests were clustered into four groups and assigned to resistance classes. For many of the genotypes there was a good correspondence between resistance classes for all test methods. Divergent results between tests were associated with foliage maturity characteristics of the genotypes. Contribution no. 3879050 of the Lethbridge Research Station.     

Evaluation of diploid potato clones for resistance to tuber soft rot induced by strains ofErwinia carotovora subsp.atroseptica,E. carotovora subsp.carotovora andE. chrysanthemi

Summary Tubers of clones from a diploid hybrid population ofSolanum phureja andS. stenotomum were screened for resistance to tuber soft rot caused by strains ofErwinia carotovora subsp.atroseptica (Eca),E. carotovora subsp.carotovora (Ecc) andE. chrysanthemi (Ech). Significant, positive correlations between resistance to the different strains and species were observed, indicating that screening for resistance to tuber soft rot could be accomplished by using just one of the three pathogens. Strains of Ecc and Ech were found to be much more virulent than strains of Eca. Inoculating with Ecc and Ech resulted in more distinct differences among susceptible, moderately resistant and resistant clones than inoculating with Eca.     

B9601-Y2溶磷解钾固氮能力及促玉米生长效果研究

为了明确淀粉芽孢杆菌B9601-Y2(Y2)的促生长机制,通过摇瓶培养,检测其溶磷解钾固氮活性;通过盆栽试验,探索Y2对玉米生长量和溶磷解钾量的影响。结果表明,在第7天时,Y2固氮量为2.9 mg/L,解钾量为13.5μg/mL;在第4天时,溶磷量达732μg/mL。与空白对照相比,Y2发酵液能增加玉米株高28.29%,根长27.21%,叶宽18.56%,鲜重80.93%,干重66.67%;提高土壤中速效氮、速效磷和速效钾含量分别为20.42%、111.01%和17.24%,提高植株氮、磷、钾含量45.46%、120.17%、68.45%。研究结果表明,Y2活化土壤中难溶性磷、钾和具有固氮能力,并能促进植株对氮、磷、钾营养的吸收利用。