玫烟色棒束孢与球孢白僵菌对桃蚜致病力对比

为选取具有杀蚜潜力的虫生真菌,采用喷雾法比较研究了玫烟色棒束孢IF-1106和球孢白僵菌BB-1339对桃蚜成蚜的致病力,并利用时间-剂量-死亡率模型估计了2菌株对桃蚜的致死剂量与致死时间。结果表明,菌株IF-1106侵染桃蚜后菌丝如棉絮状,形成淡玫瑰色分生孢子,且菌丝侵染速度快于菌株BB-1339;菌株BB-1339侵染桃蚜后菌丝短而致密,形成白色分生孢子。菌株IF-1106在浓度为1×10⁸ CFU/mL时,累计死亡率达到91.7%,而菌株BB-1339最高仅为55.0%。时间-剂量-死亡率模型中Hosmer-Lemeshow方法拟合异质性检验表明模型拟合良好,在接种后7 d,菌株IF-1106和BB-1339对桃蚜的半致死浓度分别为1.20×10⁵ CFU/mL和8.15×10⁷ CFU/mL;当浓度为1×10⁸ CFU/mL时,2菌株对桃蚜的半致死时间分别为4.2 d和6.8 d。表明菌株IF-1106对桃蚜的致病力高于菌株BB-1339,更具开发潜力。     

Cd与Zn复合胁迫对麦长管蚜生命参数及繁殖的影响

为了明确Cd与Zn复合胁迫对麦长管蚜Sitobion avenae(Fabricius)生长发育与繁殖的影响,在室内采用不同含量Cd~(2+)与Zn~(2+)溶液交互处理土壤-小麦-麦长管蚜系统,利用特定年龄生命表研究在不同含量Cd与Zn复合胁迫下麦长管蚜生命参数及繁殖的变化规律。结果表明,Cd、Zn以及Cd与Zn交互作用均极显著影响麦长管蚜的生命参数与繁殖,其中Zn对麦长管蚜种群参数的影响最大。在40 mg/kg Cd与400 mg/kg Zn复合胁迫下,麦长管蚜种群的内禀增长率、净增值率显著高于单一Cd胁迫;但不同含量Cd与800、1 600 mg/kg高含量Zn或不同含量的Zn与120、240 mg/kg高含量Cd复合胁迫时,其内禀增长率与净增值率却逐渐下降;其平均世代周期在复合胁迫条件下显著低于单一Cd胁迫。生殖力曲线面积的变化规律与种群参数的变化规律相同,推测40 mg/kg和400 mg/kg分别为Cd与Zn复合胁迫的关键含量。研究表明,低含量Cd与Zn复合胁迫能显著促进麦长管蚜生长发育,而高含量Cd与Zn复合胁迫并不能促进麦长管蚜的生长发育。     

高温胁迫对禾谷镰孢生长和致病力的影响

为探究高温胁迫对禾谷镰孢生长和致病力的影响, 本研究测定了禾谷镰孢5株耐高温菌株和4株温度敏感型菌株在25℃和30℃下的菌丝生长速率、产孢量、孢子萌发率以及不同胁迫压力下的生长速率、致病力和DON毒素含量等。结果表明, 不论耐高温菌株还是温度敏感型菌株, 30℃高温对其菌丝生长均有抑制作用, 但对产孢量和孢子萌发有促进作用;30℃高温能减轻NaCl和CaCl2胁迫对禾谷镰孢生长的抑制, 但是不影响KCl、刚果红, SDS和H2O2对病原菌的抑制作用;在30℃下, 大部分耐高温菌株的致病力不变或降低, 而大部分温度敏感型菌株的致病力反而增加, 30℃对大部分菌株的DON毒素产量有一定促进作用。研究结果可为研究气候变化下小麦赤霉病的流行和预测提供理论基础。     

桃小食心虫高致病力白僵菌菌株筛选

对来源于不同地点或寄主的14株球孢白僵菌进行僵虫率、在虫体上菌丝生长时间、产孢时间及单虫产孢量测定,综合评价各菌株对桃小食心虫幼虫的致病力,选择较好的菌株进行毒力测定。结果表明：基于僵虫率、菌丝生长时间、产孢时间及单虫产孢量4个指标,筛选出 3 株具有较强致病力的优良菌株Bb7、Bb9和Bb14;在孢子浓度为1.0×107 孢子/mL时,对桃小食心虫幼虫的致死率分别为73.33%、77.78%和80.00%, LT50分别为8.45、7.49、8.42 d;LC50分别为1.76×105、3.03×106、2.10×105孢子/mL。     

蝉拟青霉不同来源菌株的生长特性及其对蚜虫的致病性

为了筛选到生防效果好的高效蝉拟青霉菌株,对其12个不同来源菌株的生长速率、产孢量、孢子萌发率、抗紫外线能力、耐热性以及对蚜虫的致病力等进行比较。结果表明,SL和3L菌株菌落生长最快,SL5和FY菌株产孢量最高,FY和3L菌株孢子萌发率最高,FY和FJS菌株抗紫外线能力最强,3L和3716菌株耐热性最强,LB、3L菌株和3716菌株对蚜虫的致病性高,孢子和代谢物对蚜虫的致死率都在80.00%以上。经综合比较,LB菌株在致病力、产孢量、抗紫外线、抗热性等方面表现优良。     

球孢白僵菌生物学特性与其对小菜蛾致病力相关性分析

为明确球孢白僵菌的各项生物学指标与其对小菜蛾致病力间的相关性,对一株球孢白僵菌菌株GXU-Bb进行单孢分离,测定了菌株GXU-Bb及其分离子菌株GXU-Bb16、GXU-Bb10、GXU-Bb13和GXU-Bb05这5个菌株的生长速率、产孢量、孢子萌发率、胞外蛋白酶水平和几丁质酶水平等多项生物学指标。结果表明,各菌株间生长速率和孢子萌发率无显著差异;产孢量变化范围1.54×10^7-2.98×10^7个/ml;胞外蛋白酶水平变化范围1.04-1.19;几丁质酶水平变化范围1.05-1.14;各菌株间对小菜蛾二龄幼虫的致病力差异较大,校正死亡率变化范围为39.81%-83.79%。将各生物学指标与菌株对小菜蛾二龄幼虫的校正死亡率进行回归分析得出,球孢白僵菌对小菜蛾的致病力与菌株生长速率、孢子萌发率无显著相关关系;与产孢量、胞外蛋白酶水平呈极显著正相关关系;与几丁质酶水平呈显著正相关关系。     

模拟气候变暖对不同纬度带麦长管蚜和禾谷缢管蚜种群动态的影响

为明确气候变暖对不同纬度带麦田麦长管蚜Sitobion avenae和禾谷缢管蚜Rhopalosiphum padi种群动态的影响,在高纬度的河北省廊坊市(39°30′N,116°36′E)和相对低纬度的河南省原阳县(34°55′N,114°15′E)开展红外线辐射增温试验,调查廊坊市(+2.00℃)和原阳县(+1.18℃)2个试验点的增温处理小区和对照小区麦长管蚜和禾谷缢管蚜的种群动态,并计算其盛期发生比值。结果表明,增温使廊坊市试验点的麦长管蚜始见期、峰期分别提前21、7 d,使原阳县试验点的麦长管蚜始见期、峰期分别提前14、14 d;而禾谷缢管蚜的始见期和峰期仅在原阳县试验点提前31 d和7 d。增温使廊坊市试验点的麦长管蚜盛期蚜量、峰期蚜量分别显著增加了139.21%和77.83%,禾谷缢管蚜盛期蚜量和峰期蚜量分别显著增加了157.31%和130.16%;增温使原阳县试验点的麦长管蚜盛期蚜量、峰期蚜量分别显著增加了149.62%和176.52%,禾谷缢管蚜/麦长管蚜的盛期蚜量比值显著降低了43.21%。表明增温有利于高纬度地区(廊坊市)麦长管蚜和禾谷缢管蚜种群增长,而在低纬度地区(原阳县)仅有利于麦长管蚜种群增长。     

新烟碱类杀虫剂亚致死剂量对麦长管蚜和棉蚜取食行为的影响

为了明确新烟碱类杀虫剂亚致死剂量对麦长管蚜和棉蚜拒食作用的差异,通过铷标记法、蜜露法以及两种蚜虫体内总糖、总脂含量的测定研究了新烟碱类杀虫剂亚致死剂量对麦长管蚜和棉蚜取食的影响。结果表明,铷标记法和蜜露法测定的新烟碱类杀虫剂亚致死剂量对麦长管蚜的拒食率均在80%以上,而对棉蚜的拒食率均在25%以下。蚜虫体内总糖总脂含量测定结果表明,新烟碱类杀虫剂亚致死剂量处理后麦长管蚜体内总糖、总脂含量均显著低于对照,而棉蚜体内总糖、总脂含量与对照均无显著差异。三种方法测定结果一致表明新烟碱类杀虫剂亚致死剂量对麦长管蚜具有很强的拒食作用,而对棉蚜没有明显的拒食作用。     

海南芒果可可球二孢的致病力及其对多菌灵抗性

从海南5个芒果主产区采集分离芒果蒂腐病菌可可球二孢菌株,采用室内人工接种的方法对110个可可球二孢菌株进行致病力测定,采用区分剂量法和菌丝生长速率法测定其中106个菌株对多菌灵的抗性。结果表明:芒果蒂腐病自然发病率29.37%;人工接种的发病率100.00%,110株可可球二孢菌株中强致病力、中等致病力及弱致病力菌株分别占64.55%、25.45%和10.00%;在106株可可球二孢菌株中,抗性菌株发生频率为52.83%,其中高抗菌株可在含100 mg/L多菌灵培养基上生长,发生频率为45.28%,中抗菌株在含100 mg/L多菌灵培养基上不能正常生长,抗性频率为7.55%;没有发现低抗菌株。多菌灵对可可球二孢田间分离菌株EC_(50)的频率分布为不连续分布,研究结果表明海南地区危害芒果的可可球二孢对多菌灵抗性非常严重。     

烟草赤星病菌致病力分化与弱毒株抗性诱导作用的研究

对我国不同地区烟草赤星病菌(Alternaria alternata)20个菌株致病力的测定结果表明,病菌不同菌株致病力有明显的差异。菌株致病力的强弱与其生长量和产孢量有一定的关系。致病力强的菌株菌落生长慢、气生菌丝生长好、产孢量低,致病力弱的菌株则相反。据此选出11个弱毒株对烟草幼苗作诱导接种,其中菌株 TBA16可明显诱导烟苗对赤星病的抗性,当用菌株 TBA28和 TBA19挑战接种时,抗性诱导效应分别为50%—61%和60%—71.4%。     

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.     

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.     

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.     

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.