一株粪生毛壳菌的分离鉴定及其对辣椒枯萎病的防治效果

本文采用平板对峙法和抑菌圈法从76株粪生真菌中筛选出1株辣椒枯萎病生防菌株LJ-S2L1,并利用菌落直径法、纸片扩散法、室内毒力测定和盆栽试验评价了其防病效果。结果表明,菌株LJ-S2L1对辣椒枯萎病菌抑菌率达71.67%,可使辣椒枯萎病菌菌丝发生隘缩或断裂,抑菌圈直径达32 mm;菌株LJ-S2L1发酵液和无菌发酵滤液均对辣椒枯萎病菌菌丝生长有抑制作用,抑制率分别达61.57%和56.48%。毒力测定结果表明,菌株LJ-S2L1发酵液对辣椒枯萎病菌的抑制率在1000μL/m L时达到72.10%,抑制中浓度为300.63μL/m L;盆栽试验防治效果达到71.8%。根据形态学特征结合其分子系统发育树分析,将菌株LJ-S2L1鉴定为球毛壳菌Chaetomium globosum。     

油菜菌核病菌拮抗海洋细菌GM-1菌株的种类鉴定及抑菌作用研究

从连云港海域分离到1株对油菜菌核病菌有显著抑制作用的海洋细菌菌株GM-1,对其进行种类鉴定、抗菌作用测定及盆栽防病效果测定.通过形态特征观察、生理生化试验及16SrDNA序列、gyrB基因序列分析,将该菌株鉴定为芽胞杆菌属(Bacillus)的解淀粉芽胞杆菌(Bacillus amylolique faciens).抑菌作用测定结果表明:GMl菌株和无菌发酵液对油菜菌核病菌菌丝的生长具有明显的抑制作用,培养7d的抑菌带宽度分别达到30mm和16mm,GM-1菌株和无菌发酵液对菌丝细胞结构有明显的破坏作用,导致菌丝细胞壁变厚、膨大;同时对菌核的萌发有明显的抑制作用,菌液较无菌发酵液的抑制作用更显著.盆栽防病效果测定表明:该菌株菌液对油菜菌核病具有明显的防治作用,防治效果达68％,同时能够促进油菜种子萌发,显示出良好的开发应用前景.     

黄瓜白粉病拮抗细菌的筛选与鉴定及其防病机理

通过室内盆栽试验,筛选到对黄瓜白粉病具有显著防治效果(≥90.0%)的细菌12个菌株进行田间小区防病试验,结果表明其中10个菌株具有显著的防治效果,菌株XJT-7、NZT-14-84和BDT-25的防治效果较好,分别为79.02%、67.51%和57.38%。对该3株生防细菌的防病机理初步研究证明他们的胞外代谢产物具有防病作用。通过分类鉴定,确定菌株XJT-7为坚强芽孢杆菌。     

海洋细菌L1-9菌株对小麦的促生防病作用研究

采用平板对峙法和打孔法测定了海洋细菌L1-9菌株对小麦根腐叶枯病菌Bipolaris sorokiniana和小麦赤霉病菌Fusarium graminearum的抑制作用,结果表明:L1-9菌株及其发酵液对两种病原真菌的菌丝生长和分生孢子萌发均有明显的抑制作用.种子发芽试验和盆栽试验结果表明:L1-9菌株发酵液和无菌发酵液分别处理小麦种子后,能显著提高小麦种子的发芽率、发芽势、出苗率以及小麦幼苗的株高、根长和干重,促进小麦幼苗的生长.该菌株对小麦根腐叶枯病和小麦赤霉病具有较好的防病效果,发酵液的防效分别达到82.00%和73.84%,发酵液的抑菌防病作用显著高于无菌发酵液.     

娄彻氏链霉菌XL-6的抑菌活性及对茄子幼苗的防病促生效应

本文研究了娄彻氏链霉菌Streptomyces rochei XL-6无菌发酵液在自然状态下的抑菌活性及对茄子幼苗的防病促生效果。结果表明,菌株XL-6发酵液的抑菌活性物质可耐70℃高温,在pH 5~8其抑菌活性保持稳定;该抑菌活性物质不受紫外线、蛋白酶K和胰蛋白酶的影响,在4℃条件下贮藏28 d仍可保持良好的抑菌活性。采用不同浓度的发酵液处理茄子幼苗均可提高茄苗对青枯病的抗性,其中,施用40倍发酵液显著降低茄子青枯病发病率和病情指数并显著提高PAL和PPO酶活性,对盆栽茄子的防治效果达64.78%。同时,40倍发酵液显著提高茄子种子发芽率、鲜重、叶绿素含量及根系活力,较病原菌菌体处理和无菌水处理,茄苗干重增幅分别达15.81%和27.95%,对茄苗的促生效果显著。说明适宜浓度的拮抗菌XL-6发酵液兼具防治茄子青枯病和促进植株生长的效果。     

2株拮抗放线菌复合防治番茄青枯病的研究

为克服单一拮抗菌抑菌活性不够稳定、防治效果差等不足,本文研究了2株优良放线菌菌株之间亲和性及其复合对番茄青枯病的防治效果表明,2株菌之间无明显拮抗作用,将亲和性菌株FX81和FX28等比例同时复合发酵,复合发酵液对番茄青枯病菌的抑菌圈直径达36.0 mm,抑菌效果明显高于单一菌株FX81（27.0 mm）和FX28（28.8 mm）。将2株拮抗菌制成复合菌剂BOF8128对番茄青枯病的盆栽防效为82.03%,比单一菌剂分别提高了8.13%（BOF81）和18.63%（BOF28）,同时复合菌剂显著促进了番茄地上部分的生长,干重增加76.58%。由此表明,2株放线菌在防治番茄青枯病方面具有协同增效的作用,有望用于进一步菌肥的开发和应用。     

辣椒溶杆菌NF87-2防治瓜类蔬菜蔓枯病的研究

由黑腐球壳菌Didymella bryoniae引起的瓜类蔬菜蔓枯病是一种重要真菌土传病害,造成瓜类蔬菜生产上重大的经济损失。本研究以蔓枯病菌DB-20为靶标菌,采用平板对峙培养法,测定了拮抗细菌及其代谢产物对蔓枯病菌菌丝生长和孢子萌发的的室内抑制作用,拮抗细菌和蔓枯病菌同时接种后,测定西瓜种子的发芽率和出苗率,采用盆栽试验研究拮抗细菌对黄瓜蔓枯病的防治效果。结果表明,辣椒溶杆菌Lysobacter capsici NF87-2对蔓枯病菌菌丝生长的室内抑制率为81.6%,菌株NF87-2及其次生代谢物对蔓枯病菌孢子萌发的抑制率分别为59.4%和67.2%。蔓枯病菌DB-20处理的京欣一号西瓜种子发芽率和出苗率分别为48%和38%,菌株NF87-2＋DB-20同时接种处理组的西瓜种子发芽率和出苗率分别为83%和82%。菌株NF87-2发酵液及其代谢产物对黄瓜蔓枯病的盆栽防治效果分别为81.6%和66.5%。辣椒溶杆菌NF87-2是一株具有较好生防应用潜力的拮抗菌株,有望开发成防治瓜类蔬菜蔓枯病的生物杀菌剂。     

小麦茎基腐病生防菌株YB-161的分离鉴定及防效测定

为筛选防治小麦茎基腐病的高效生防菌株,采用稀释涂布法从小麦茎基腐病病土中分离细菌,以假禾谷镰孢Fusarium pseudograminearum为靶标菌,通过平板对峙培养法和室内盆栽试验筛选优良菌株并测定其田间防治效果,分析优良菌株发酵滤液对假禾谷镰孢的抑菌能力,并结合形态特征、Biolog微生物自动鉴定系统和gyrA序列分析对其进行种类鉴定,以及测定该菌株的抑菌谱。结果表明,10份供试土样中共分离到98株细菌,对假禾谷镰孢的菌丝生长抑制率超过40.00%的菌株有14株,其中菌株YB-161对假禾谷镰孢的菌丝生长抑制率最高,达63.50%。室内盆栽试验结果显示,菌株YB-161处理小麦的病情指数最低,为31.40,对小麦茎基腐病的防治效果最好,为68.15%,其对小麦也表现出较好的促生作用。田间调查结果显示,菌株YB-161菌液拌种处理对小麦茎基腐病的田间防治效果高于52.35%,并对小麦具有一定的增产作用。菌株YB-161的发酵滤液5倍稀释液和10倍稀释液对假禾谷镰孢的菌落抑制率分别达66.67%和44.33%,该菌株被鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens。此外,菌株YB-161对辣椒炭疽病菌Colletotrichum capisci、烟草疫霉病菌Phytophthora parasitica等5种植物病原真菌均有较好的拮抗作用。表明生防菌株YB-161对绿色防控小麦茎基腐病具有良好的开发利用潜能。     

海洋细菌解淀粉芽胞杆菌SH-27在大豆体内的定殖动态及促生防病作用

为明确海洋细菌SH-27在大豆体内的定殖动态及其促生长作用和对大豆疫病的防治效果，本研究采用抗利福平标记法和平板对峙生长法，筛选对利福平标记稳定且对大豆疫霉菌具有较好抑菌作用的标记菌株SH-27^Rif，培养10代后的标记菌株SH-27^Rif能够保持稳定，对大豆疫霉抑制率为56.92%。分别采用灌根和涂叶法研究其在大豆体内的定殖动态，灌根与涂叶法均可使标记菌株SH-27^Rif在大豆体内定殖，时间达31 d以上；灌根处理定殖量呈先升后降趋势，定殖量根 > 茎 > 叶，处理后第21 d根部定殖量达到最大（6.6×10⁵ cfu/g）；涂叶处理第1 d大豆叶片定殖量达到最大（6.3×10⁵ cfu/g），随后呈迅速下降趋势；定殖量叶>茎，根部未检测到标记菌株SH-27^Rif。盆栽促生试验结果表明，菌株SH-27发酵液灌根处理第15 d，处理组株高、根长、茎粗、鲜重、干重、叶绿素含量、根系活力等指标均显著高于对照组。盆栽防病试验结果表明：菌株SH-27发酵液灌根处理能显著降低大豆疫病的病情指数，对大豆疫病3、5、7和9 d的防效分别为83.44%、66.34%、57.18%和52.85%。以上研究结果表明海洋细菌SH-27是防治大豆疫病的潜在生防菌株，具有良好的开发和应用价值。     

巨大芽胞杆菌YB-3的筛选、鉴定及其对生姜青枯病的生防效果研究

青枯病（bacterial wilt）是生姜上的一种细菌土传毁灭性病害,化学防治易污染环境且常规化学药剂很难在土壤中起到持续控病的作用,生物防治是其理想的防治方法。为开发对生姜青枯病有效的生防措施,对从生姜根际土壤中分离的一株生防细菌YB-3进行了鉴定,并对其生物学特性及生防效果进行了研究,以丰富生防菌株资源库。采用抑菌圈法筛选拮抗细菌,对效果最好的拮抗菌株做盆栽试验,测定其对生姜青枯病的防治效果,根据形态特征、生理生化特性以及16S rDNA序列对筛选得到的优良菌株进行鉴定。试验结果表明,该拮抗菌在平皿上对青枯菌的抑菌率为50.67%,盆栽试验对青枯病的防治效果为60.86%;经16S rDNA序列分析,并结合形态学和生理生化特征,将菌株YB-3鉴定为巨大芽胞杆菌Bacillus megaterium。YB-3是一株具有开发利用价值的姜青枯病生防菌株。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Richtlinien der Verbände des ökologischen Landbaus zum Vorratsschutz

Zusammenfassung Verbände des ökologischen Landbaus wie z. B. Bioland, Gäa, Demeter; Naturland, Ernte für das Leben oder Bio Suisse beschränken ihre Mitglieder bei der Wahl von Vorratsschutzmaßnahmen. Vorrang besitzen Maßnahmen zur Vermeidung von Schädlingen gegenüber Bekämpfungsmaßnahmen. Fallen müssen zur Befallsüberwachung eingesetzt werden, um einen Befall durch Vorratsschädlinge frühzeitig zu erkennen. Diese Maßnahmen sollen den weitgehenden Verzicht auf chemisch-synthetische Mittel ermöglichen. In diesem Beitrag werden die Empfehlungen der Verbände mit den derzeit verfügbaren chemischen Mitteln für den Vorratsschutz abgeglichen. Erfahrung in der praktischen Umsetzung von physikalischen und biologischen Verfahren werden diskutiert und Defizite bei der Befallsüberwachung und Bekämpfung beschrieben.     

Development of protocols for detection of Colletotrichum acutatum and monitoring of strawberry anthracnose using real-time PCR

Real-time PCR (TaqMan®) assays were developed for the specific detection and discrimination of Colletotrichum spp., C. acutatum and C. gloeosporioides causing anthracnose in strawberry using the most divergent area of the internal transcribed spacers (ITS1 and ITS2) and 5·8S ribosomal RNA (rRNA) gene region. The specificity of the new assays was tested using DNA from six species of Colletotrichum and nine fungal species commonly found associated with strawberry material, and additionally by comparing the sequences with those from databases using a blast search. The sequences only showed identity with homologous sequences from the desired target organisms. The new assays were 10–100 times more sensitive than conventional PCR methods previously published for the diagnosis of strawberry anthracnose. When real-time PCR was compared with ELISA methods, PCR improved the sensitivity of the identification by obtaining positive results for samples of strawberry plant material that tested negative with ELISA. The development of C. acutatum was monitored using artificially infected strawberry crowns from two strawberry cultivars (Camarosa and Ventana) and a real-time PCR assay specific for this species between January and June 2006. The amount of C. acutatum detected using real-time PCR varied significantly by month ( P  < 0·001), but not by cultivar ( P  = 0·394). The new assays were shown to be useful tools for rapid detection and identification of these pathogens and to allow rapid and accurate assessment of the casual agents of anthracnose in strawberry.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.