Prospects of a fungus-contamination device for the control of tsetse fly Glossina fuscipes fuscipes

The prospects of the fungus Metarhizium anisopliae (Metsch.) Sorok. applied in contamination devices (Cds) to control tsetse fly Glossina fuscipes fuscipes Newstead was tested in a field experiment in Lake Victoria from 2 March 1999 to 31 August 2000. One hundred and sixty pyramidal traps mounted with Cds were deployed along the lakeshore and rivers on Mfangano Island. Contamination devices were loaded with 1.5-2.0 g of dry conidia/Cd. On the second island, Nzenze Island, four pyramidal traps fitted with plastic bags were deployed and served as the conventional 'trap and kill' population suppression method. A third island, Ngodhe Island, remained untreated and served as a control. Cds were recharged monthly with fresh conidia; plastic bags were also changed monthly. The apparent changes in population density were monitored weekly using biconical traps set at random on the three islands. To assess the incidence of M. anisopliae in tsetse flies on Mfangano Island, flies captured during monitoring were maintained in the laboratory and their mortality recorded. Fly population was reduced to 82.4 and 95.8% relative to untreated control on Mfangano and Nzenze islands, respectively, during the experimental period. Compared to the fungus-treated island, the number of flies caught in monitoring traps increased considerably in 'trap kill' treatment at 5 months after the treatments were removed. The incidence of M. anisopliae in fly populations was low during the 12 weeks following the initiation of the experiment but increased afterward until termination of the treatment. M. anisopliae could still be recovered from fly populations at 3 months after termination of the treatment, although the incidence was low. The results of this study have shown that application of M. anisopliae in a contamination device can suppress the population of G. fuscipes fuscipes comparable to the 'trap and kill' technology.     

Effects of chemical and botanical insecticides used for locust control on Metarhizium anisopliae var. acridum conidia after short- to medium-term storage at 30°C

The short- to medium-term viability and growth of Metarhizium anisopliae var. acridum conidia were investigated when combined with six insecticides, at three different concentrations. All of the insecticides used in this study were suitable for immediate spraying with M. anisopliae var. acridum conidia except for fenitrothion. Fipronil, teflubenzuron, and fenitrothion formulations significantly reduced conidial viability over time. The 10% teflubenzuron treatment caused loss of viability relatively quickly with 9.9% germination after 28 days. Mycelial growth was affected by all the treatments except fenitrothion.     

Interaction Between the Entomopathogens Beauveria bassiana, Metarhizium anisopliae and Paecilomyces fumosoroseus and the Mycoparasites Clonostachys spp., Trichoderma harzianum and Lecanicillium lecanii

Biocontrol agents of numerous insect pests and fungal pathogens exist but virtually nothing is known about their interaction if used simultaneously. Our objective was to investigate the compatibility of the entomopathogens Beauveria bassiana, Metarhizium anisopliae and Paecilomyces fumosoroseus, and the broad host-range mycoparasites Clonostachys spp., Trichoderma harzianum and Lecanicillium lecanii. In vitro host-range tests revealed that M. anisopliae was highly susceptible to all mycoparasites tested. B. bassiana was attacked by Clonostachys rosea, and P. fumosoroseus. was resistant to mycoparasites. M. anisopliae but not P. fumosoroseus killed nymphs of Bemisia tabaci in bioassays. B. bassiana and M. anisopliae proved lethal to Cosmopolites sordidus, Diatraea saccharalis and Sitophilus oryzae. Coapplication of mycoparasites with entomopathogens did not affect their biocontrol efficacy in vivo, although the reisolation success of entomopathogens could be significantly reduced, especially from smaller insect species. Trichoderma spp. were reisolated from mycoparasite-treated insects more frequently than C. rosea. The coapplication of the highly susceptible M. anisopliae generally enhanced mycoparasite recovery. Mycofungicide preparations caused some insect mortality but less than a copper hydroxide fungicide which is still permissible in organic agriculture. We concluded that the tested entomopathogens and mycoparasites are compatible elements of integrated pest management.     

Biological control of Strophosoma spp. (Coleoptera: Curculionidae) in greenery (Abies procera) plantations using Hyphomycetes

In Abies procera plantations Strophosoma melanogrammum and S. capitatum cause economic damage due to the adult stage feeding on the needles. No chemical treatments of these weevils are allowed in Denmark, so the potential of biological control was evaluated. We studied pathogenicity of thirteen isolates of entomopathogenic fungi and the field effect of soil application of Metarhizium anisopliae against Strophosoma spp. All of the tested isolates were capable of causing infections under laboratory conditions and average survival time at 20°C ranged between 13 and 23 days for S. melanogrammum and between 23 and 28 days for S. capitatum when dipped in a fungal suspension adjusted to 1×10⁷ conidia mL^-1. Under field conditions up to 90% of the living collected individuals died due to M. anisopliae infection in the treated plots, whereas less than 1% died of M. anisopliae infection in control plots. In accordance, the population of Strophosoma spp. was reduced in plots where the fungus was applied compared to control plots.     

Environmental contamination with Metarhizium anisopliae from fungal bands for control of the Asian longhorned beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae)

Our objective was to determine whether conidia from non-woven fiber bands impregnated with Metarhizium anisopliae F 52 could be spread to other parts of the environment, and whether Anoplophora glabripennis could become infected with conidia dispersed from fungal bands. In the field, bands containing M. anisopliae were hung at 3 m height on 15 trees. Bark samples were taken 10, 20, and 30 cm above the bands and 10, 30, and 60 cm below the bands 2, 5, and 9 days after band placement to quantify conidial densities. There were more conidia in samples taken below bands compared with samples taken above bands. A significant positive correlation was found between rainfall and the occurrence of conidia on any of the bark samples. A laboratory study was conducted to determine whether conidia from M. anisopliae fungal bands could be spread to other parts of the environment by A. glabripennis adults and whether A. glabripennis could become infected by conidia dispersed from fungal bands. One or five adult A. glabripennis were used to contaminate artificial environments with conidia. All adults subsequently exposed to contaminated environments were killed by fungal infection. Beetles exposed to environments that had been contaminated by five beetles died in fewer days compared with environments contaminated by one beetle. Beetles in both density treatments died in fewer days than beetles exposed to environments without M. anisopliae conidia. Our results indicate that environmental contamination with conidia from fungal bands can occur, and that adult A. glabripennis can acquire infection from a contaminated environment.     

Persistence of Conidia of Metarhizium anisopliae in Sugarcane Fields: Effect of isolate and formulation on persistence over 3.5 years

Metarhizium anisopliae is being used in Australia as a biopesticide for control of sugarcane whitegrubs in soil. The field persistence in sugarcane soil of two isolates of M. anisopliae each in four formulations was tested by mixing the formulation with soil which was then placed in PVC rings and buried in sugarcane fields. The two isolates used were FI-1045, M. anisopliae var. anisopliae, the active ingredient in BioCane™ currently used for greyback canegrub control, Dermolepida albohirtum (Coleoptera: Scarabaeidae: Melolonthinae), and FI-147, M. anisopliae var. lepidiotum, being tested as a biopesticide for Lepidiota spp. (Coleoptera: Scarabaeidae: Melolonthinae) and other species of canegrub. The four formulations were rice granules (as in BioCane™), a wettable powder derived from conidia screened from the rice granules, conidia off rice suspended in water and conidia produced on agar plates, dried, and then mixed with water for adding to soil. FI-1045 was tested at three different sites in north Queensland with a range of soil types and climatic conditions while FI-147 was tested at three similarly diverse sites in southern Queensland. The PVC rings were destructively sampled every 6 months for 3.5 years and the number of viable conidia remaining determined by plating onto a selective medium. The exponential decay was determined. Monthly decay rates ranged from 0.0309 to 0.0835 (mean 0.0512). A small proportion of conidia survived the 3.5 years at all sites and all formulations. Overall, isolate FI-147 persisted better than FI-1045, but was used at the more Southerly sites. Rainfall and soil type had negligible effects on persistence. The agar-produced FI-147 conidia declined most slowly, while the two rice-produced but water-formulated conidia gave similar results. Isolate FI-1045 survived best as the BioCane™ formulation and this rice granule formulation was almost as persistent as the agar conidia with FI-147. A small proportion of conidia, in some formulations and at some sites, were recovered from immediately below the rings. This movement was thought to be due to activity of earthworms or mites. The results suggest that 3 years would be the maximum period for a BioCane™ formulation to provide some level of infection in the target pest unless augmented by conidia from infected grubs. The effectiveness of these new conidia may be reduced due to their highly aggregated distribution.     

Laboratory investigations on the potential of entomopathogenic fungi for biocontrol of Helicoverpa armigera (Lepidoptera: Noctuidae) larvae and pupae

The susceptibility of third instar Helicoverpa armigera to seven strains of three entomopathogenic fungal species, i.e. Metarhizium anisopliae, Beauveria bassiana and Paecilomyces fumosoroseus, was tested under laboratory conditions using the larval immersion method. High efficacies ranging from 68 to 100% corrected mortality were recorded with more profound effects in treatments with B. bassiana and P. fumosoroseus strains. The median lethal concentration (LC₅₀) for L3 was 6.0×10⁵ in M. anisopliae 79, 1.5×10⁵ in B. bassiana 124 and 4.2×10⁴ in P. fumosoroseus 14. These three strains were further used to characterize the age-dependent mortality of different larval stages (L2-L5) and the effect against pupae of H. armigera. Larval stages did not differ in their mortality but differed i in median lethal time, with shorter values recorded in the second instar. Tested fungi also caused a high reduction between 74.4 and 100% in the emergence of pupae using the soil inoculation method and the pupal immersion technique. All three fungal species, especially P. fumosoroseus, have a high potential for biocontrol of H. armigera larvae and also as a soil treatment targeting the pupae.     

中国西南高黎贡山绿僵菌物种多样性及其垂直分布特征

云南高黎贡山具有多样化的生态系统和生物资源。为探清该地区绿僵菌属(Metarhizium)真菌的物种多样性及其不同海拔的垂直分布特征, 沿海拔梯度(600-3,800 m)在7种典型植被类型(I: 干热河谷; II: 季风常绿阔叶林; III: 暖性针叶林; IV: 中山暖性常绿阔叶林; V: 山地苔藓矮林; VI: 寒温性灌丛或草甸; VII: 流石滩稀疏植被)中调查绿僵菌资源。从生境土壤中分离菌株, 通过多基因(nrSSU、nrLSU、EF-1α、RPB1和RPB2)系统发育分析进行物种鉴定。结果表明, 高黎贡山绿僵菌物种资源丰富, 获得的161株菌株分属于12个物种(Metarhizium rileyi, M. viridulum, M. lepidiotae, M. brunneum, M. pingshaense, M. anisopliae, M. robertsii, M. guizhouense, M. indigoticum, M. pemphigi, M. campsosterni和Metacordyceps neogunnii), 其中M. indigoticum为中国新记录种, M. anisopliae complex中的物种(8种)较集中; 同时还采集到了绿僵菌的近缘属Nigelia属物种N. martiale。高黎贡山绿僵菌广泛分布于除类型VII (海拔3,600-3,800 m)外的6种植被类型(海拔600-3,400 m)中。中低海拔植被类型(I-IV)中菌株数量较多(≥23株)、物种多样性较高(4-9种), 而高海拔植被类型(V-VI)中菌株数量较少(2-8株)、物种较单一(1-2种)。中海拔的常绿阔叶林中绿僵菌资源最丰富, 其中季风常绿阔叶林(植被类型II)中的菌株数量(52株, 占总数的32.3%)和物种数(9种)最多; 中山湿性常绿阔叶林(植被类型IV)为其次(47株, 占总数的29.2%; 7种)。高黎贡山绿僵菌优势种现象明显, M. brunneum为最优势物种, 其菌株数占总数的46.6%, 在生境条件差异很大的6种植被类型(I-VI)中都存在, 说明该物种生态适应能力最强。     

Review on safety of the entomopathogenic fungus Metarhizium anisopliae

The entomopathogenic fungus Metarhizium anisopliae (Metschn.) Sorokin is widely used for biocontrol of pest insects, and many commercial products are on the market or under development. The aim of this review is to summarise all relevant safety data of this fungus, which are necessary for the commercialisation and registration process. The review contains the following sections: (1) identity, (2) biological properties (history, natural occurrence and geographical distribution, host range, mode of action, production of metabolites/toxins, effect of environmental factors), (3) methods to determine and quantify residues, (4) fate and behaviour in the environment (mobility and persistence in air, water and soil), (5) effects on non-target organisms (microorganisms, plants, soil organisms, aquatic organisms, predators, parasitoids, honey bees, earth worms, etc.), (6) effects on vertebrates (fish, amphibia, reptiles, and birds), and (7) effects on mammals and human health (allergy, pathogenicity/toxicity). On the basis of the presented knowledge, M. anisopliae is considered to be safe with minimal risks to vertebrates, humans and the environment.     

Evaluation of the Entomopathogenic Fungi Metarhizium anisopliae and Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) for Control of the Green Leafhopper Empoasca decipiens (Homoptera: Cicadellidae) and Potential Side Effects on the Egg Parasitoid Anagrus atomus (Hymenoptera: Mymaridae)

The efficacy of Metarhizium anisopliae strain Ma43 and Paecilomyces fumosoroseus strain Pfr12 (both Deuteromycotina: Hyphomycetes) against adults of Empoasca decipiens (Homoptera: Cicadellidae) and potential side effects on the egg parasitoid Anagrus atomus (Hymenoptera: Mymaridae), were investigated in greenhouse cage and laboratory experiments. Treating leafhopper-infested faba bean plants at a dose rate of 1×10⁷ conidia mL^-1 resulted in up to 97% mortality 7 days after application and a 100% infection rate. Experiments on the residual effects revealed a significant decrease in adult E. decipiens mortality with increasing time from application to insect release. The decrease in mortality over time corresponded well with data from conidia germination tests. The germination of conidia on agar medium after washing them from the surafce of sprayed plants declined significantly from 95 and 96% immediately after application for M. anisopliae Ma43 and P. fumosoroseus Pfr12, respectively, to 29 and 27% 5 days later. Experiments on potential side effects of the entomopathogenic fungi on A. atomus showed that the tested isolates had no influence on adult emergence and longevity; however, the rates of parasitism were significantly reduced by the fungal treatments. The latter might be due to either density effects and/or could indicate that A. atomus avoids fungal-treated plants. However, the parasitoid is substantially less susceptible to the fungal strains tested than the host itself.     

A mathematical model on the effect of M. denticulata weed on different winter crops

Many weeds interfere with the productivity of wheat and other winter annual crops; however, one common weed Medicago denticulata, appears to have a beneficial effect. An experiment was conducted at Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, Jharkhand to observe the effect of M. denticulata (a legume) on different crops yield of barley (Hordeum vulgare Sensu lato), linseed (Linum usitatissimum L.), Indian mustard [Brassica juncea (L.) Czernj. & Cosson] and wheat (Triticum aestivum L.). The commensalisms interaction was studied, in which one species benefits, while the other is unaffected, between the crops, M. denticulata and other weeds, to observe the role of medicago as biological control agent of other weeds for enhancement of crop productivity. Further, a statistical test was performed to establish the effect of M. denticulata and weed infestations based on one-step Markov structure of the covariance matrix of the biomass. This permitted development of a mathematical model of a crop–M. denticulata–other weeds system and their interactions through direct and indirect competition for resources. Crops yield decreased considerably due to the presence of other weeds, while it increased due to introduction of medicago and hence medicago acted as a controlling agent in a crop–M. denticulata–other weeds system. Our mathematical analysis supported the experimental findings. The model parameters are estimated through a nonlinear least square and stochastic differential equations. Moreover, some thresholds for the growth of medicago population came out from our analysis that may be used as a biological control threshold for the enhancement of crop productivity.     

Laboratory and glasshouse evaluation of entomopathogenic fungi against the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), on tomato, Lycopersicon esculentum

Forty isolates of entomopathogenic fungi from six genera were assessed against the two-spotted spider mite, Tetranychus urticae, in a single dose, direct application laboratory bioassay on tomato leaflets. Only three isolates caused greater mortality than the control: these were Metarhizium anisopliae 442.99, Hirsutella spp. 457.99, and Verticillium lecanii 450.99. These isolates were assessed in a multiple dose bioassay, together with three isolates cultured from commercial biopesticides as follows: Beauveria bassiana 432.99 (cultured from 'Naturalis-L', Troy Biosciences, Phoenix, TX, USA); Hirsutella thompsonii 463.99 (cultured from 'Mycar', Abbott Laboratories USA); and V. lecanii 19.79 (used in 'Mycotal' Koppert BV, The Netherlands). Beauveria bassiana 432.99, H. thompsonii 463.99, M. anisopliae 442.99, and V. lecanii 450.99 were all pathogenic to T. urticae in this bioassay. In addition, it was found that the mortality caused by B. bassiana 432.99 and Naturalis-L was increased when the mites were exposed to tomato leaflets sprayed previously with conidia suspensions, compared to spraying the mites directly. In a glasshouse experiment, sprays of B. bassiana 432.99, H. thompsonii 463.99, M. anisopliae 442.99, V. lecanii 450.99 and Naturalis-L reduced T. urticae populations in a tomato crop grown according to commercial practice. Naturalis-L reduced T. urticae numbers by up to 97%. In a second glasshouse experiment, single sprays of Naturalis-L and the acaricide fenbutatin oxide (Torq) were compared as supplementary treatments to release of the predatory mite, Phytoseiulus persimilis. Supplementary sprays of fenbutatin oxide reduced the numbers of T. urticae nymphs (80% reduction), while Naturalis-L reduced numbers of T. urticae adults, nymphs and eggs (98% reduction in all three cases). It is concluded that Naturalis-L has the potential to be used against T. urticae on glasshouse tomato crops.     

超声波对铜绿微囊藻与蛋白核小球藻生理特征及竞争生长的影响

铜绿微囊藻是常见的水华蓝藻,常常在湖泊中与蛋白核小球藻共存或竞争生长。超声波可用于藻华即时治理,能够降低藻类生理活性,影响藻类生长,还可能改变藻类种间竞争关系。为了探究超声胁迫(35 kHz,0.035 W·cm^-3)对铜绿微囊藻与蛋白核小球藻的生理特征及种间竞争的影响,本研究设置纯藻组和1:1混合组(细胞浓度比)进行试验。结果表明: 铜绿微囊藻对超声胁迫更加敏感。超声处理600 s后,铜绿微囊藻的光合活性(F_v/F_m)和酯酶活性存在显著变化,纯藻组和混合组的F_v/F_m分别降低了51.8%和64.7%。而各组中蛋白核小球藻的光合活性变化较小。同时,铜绿微囊藻释放的荧光溶解性有机物(类色氨酸、类酪氨酸、类富里酸物质)含量多于蛋白核小球藻。两种藻的细胞浓度对超声波的响应也不同,蛋白核小球藻变化较小,而铜绿微囊藻的细胞浓度出现不同程度的下降。尤其是600 s超声处理大幅降低了混合组中铜绿微囊藻的细胞浓度(-42.6%),在超声胁迫解除后的8 d内蛋白核小球藻占优势,种间关系由铜绿微囊藻单边抑制蛋白核小球藻转变为两者互相抑制。在超声处理后,铜绿微囊藻的活性能够逐渐恢复,为了提高控藻效果的持久性,建议在一周后再次进行超声处理。     

基于多基因分析对我国红曲霉属Monascus真菌的系统发育研究

红曲霉属Monascus具有重要的经济和生态价值,但对该属的物种识别和系统发育学研究有限。本研究首先对红曲霉属红色组内物种开展ITS和LSU序列的测定并综合分析,结合GenBank中相关物种序列及菌株的形态学特征,探讨红曲霉属的系统发育关系,鉴定出红色组3个种,弗罗里达组7个种。其次采用红曲霉色素表型控制基因簇部分基因pksKS序列进行分析,以期解决ITS和LSU等基因序列分析无法有效区分红色红曲与紫色红曲不同形态种的问题。通过分子克隆测序与直接测序结果的比较,以及对3个血红红曲菌株单核苷酸多态性的分析,解析了血红红曲种内遗传差异,首次在红曲霉属真菌中发现疑似红色红曲血红自然杂交种。最后综合ITS、LSU、pksKS序列和形态学分析的结果,统一了红曲霉属内物种的系统发育关系,确认红色组包括3个种：红色红曲M. ruber、紫色红曲M. purpureus、血红红曲M. sanguineus;发现3个变种：红色红曲发白变种M. ruber var. albidulus、紫色红曲橙色变种M. purpureus var. aurantiacus及紫色红曲火红色变种M. purpureus var. rutilus;弗罗里达组包括7个种：弗罗里达红曲M. floridanus、苍白红曲M. pallens、新月红曲M. lunisporas、阿根廷红曲M. argentinensis、累西腓红曲M. recifensis、黄色红曲M. flavipigmentosum、蜂蜜红曲M. mellicola。另外,发现1个疑似杂交种：红色红曲血红杂种M. ruber × sanguineus。结果表明,红曲霉属具有丰富的物种多样性,而且通过多基因和形态学分析可以将相近种区分开来。     

黄河三角洲盐碱地不同植被模式的土壤改良效应

黄河三角洲是我国滨海盐碱地的重要分布区,种植植被是盐碱地绿色改良的主要生态修复措施。为探讨滨海盐碱地不同植被模式的土壤改良效应,探索适宜植被模式,选取黄河三角洲盐碱地竹柳+NyPa草、旱柳+NyPa草、柽柳+紫花苜蓿、白蜡+柽柳+紫花苜蓿4种林草措施为研究对象,以纯竹柳为对照,测定土壤水分物理参数、盐碱含量、土壤养分及微生物数量等20个指标,并利用主成分分析、聚类分析和模糊数学隶属函数等统计方法评价了不同植被模式的土壤改良效应。结果表明: 林草复合模式可显著改善滨海盐碱地的土壤理化性能,增加土壤孔隙度和贮水量,降低土壤密度,提高土壤有机质、速效养分含量和土壤微生物数量。其中,白蜡+柽柳+紫花苜蓿的乔灌草混交模式在压碱抑盐、增加土壤养分和微生物数量的效果最好,而旱柳+NyPa草的乔草混交模式改良土壤水分物理性能的效果最好。不同植被模式对黄河三角洲滨海盐碱地的综合改良效应表现为白蜡+柽柳+紫花苜蓿>旱柳+NyPa草>竹柳+NyPa草>柽柳+紫花苜蓿。     

云南滇池入侵虾虎鱼类的共存策略

虾虎鱼类是入侵种的一个重要来源,常数种共同入侵同一区域,其种间如何实现共存是当前鱼类入侵生态学的一个重要科学问题。本研究通过形态分析、空间分布调查及摄食分析等方法,从形态分化和生态位分化角度揭示滇池新入侵的粘皮鯔虾虎鱼与先期入侵近缘种的共存策略。结果表明: 粘皮鯔虾虎鱼与小黄黝鱼、子陵吻虾虎鱼、波氏吻虾虎鱼等先期入侵种在形态上存在显著差异。其空间分布在研究区域上与上述物种存在显著差异,空间生态位指数显著高于其余物种。摄食分析显示,粘皮鯔虾虎鱼的食物多样性指数显著高于其余物种;其主要摄食种类为圆形盘肠溞和腺介虫等,与其他虾虎鱼类主要摄食种类也存在明显差异。在摄食生态位上,滇池入侵虾虎鱼类存在显著分化。这说明形态差异、空间生态位分化及营养生态位分化降低了种间竞争强度,促进了粘皮鯔虾虎鱼与先期入侵虾虎鱼类实现共存。粘皮鯔虾虎鱼可能凭借摄食策略上的优势在种群数量、占据栖息地范围上优于竞争对手,成为研究区域入侵虾虎鱼类中的优势种群。     

Host specificity testing and suitability of a European biotype of the braconid parasitoid Microctonus aethiopoides as a biological control agent against Sitona lepidus (Coleoptera: Curculionidae) in New Zealand

The European biotype of the parasitoid Microctonus aethiopoides Loan (Hymenoptera: Braconidae) is being considered for release against Sitona lepidus Gyllenhal (Coleoptera: Curculionidae) in New Zealand. Host specificity was evaluated in the laboratory using both endemic and introduced weed biological control curculionid species, with 12 no-choice and three choice experiments carried out comparing the S. lepidus and test weevils. Two further no-choice tests used the Moroccan M. aethiopoides biotype to compare attack rate between European and Moroccan M. aethiopoides, the latter released in 1982 to control the lucerne pest S. discoideus. Across all experiments, total parasitism of S. lepidus was 69% compared with 15% for the test weevils. European M. aethiopoides was able to develop in the native weevils Irenimus aequalis, Nicaeana cervina, Catoptes cuspidatus, Protolobus porculus and Steriphus variabilis with parasitism rates of 13, 28, 2, 7 and 8%, respectively. These levels were significantly less than those in the corresponding S. lepidus control. Total parasitism of I. aequalis and C. cuspidatus increased significantly in the presence of S. lepidus than recorded under no-choice conditions. The presence of European M. aethiopoides caused minor, if any, test weevil mortality prior to the onset of prepupal emergence and there was no significant reproductive suppression in parasitoid-exposed test weevils. Parasitism of the introduced weed control agent R. conicus by European M. aethiopoides was significantly lower (1.1%) compared to the Moroccan biotype (47.5%). Based on these and other experiments, should the European M. aethiopoides be released as a biological control agent of S. lepidus, its ecological impacts are likely to be less severe than those already exhibited by the Moroccan M. aethiopoides.     

外来水生植物大聚藻的生态安全性初探

从外来水生植物大聚藻的耐寒性、再生能力和耐盐性等方面入手,研究比较了其与有害植物水花生对环境适应能力的差异。结果表明:大聚藻的越冬能力明显高于水花生;大聚藻断枝离体水培后复活快、发根与生长迅速,生长量与营养繁殖力也明显大于水花生;大聚藻具有很强的耐盐能力,其枝条在NaCl 盐浓度为0 g·L^-1～3 g·L^-1 的水体中能正常生长,4 g·L^-1～5 g·L^-1的浓度中可存活2～4 周。因此,大聚藻在自然生态环境中具有超强的生存能力和繁殖能力,存在一定的生态风险,对大聚藻的利用必须在有限范围内谨慎进行,应严格控制其群体在自然生态环境中的过量扩散与繁殖。     

Antiviral activity of the volatile oils of Melissa officinalis L. against Herpes simplex virus type-2

Melissa officinalis L. (Lamiaceae) has been used in a variety of practical applications in medical science. Our objective in the current study was to determine the effects of the volatile oil components of M. officinalis on Herpes simplex virus type 2 (HSV-2) replication in HEp-2 cells. Four different concentrations (25, 50, 100, 150 and 200 μg/ml) of volatile oils were examined. Experiments were carried out using HEp-2 cells. M. officinalis volatile oil was found to be non-toxic to HEp-2 cells up to a concentration of 100 μg/ml. It was, however, found to be slightly toxic at a concentration over of 100 μg/ml. The antiviral activity of non-toxic concentrations against HSV-2 was tested. The replication of HSV-2 was inhibited, indicating that the M. officinalis L. extract contains an anti-HSV-2 substance.     

Whey for mass production of Beauveria bassiana and Metarhizium anisopliae

Spore production of Beauveria bassiana and Metarhizium anisopliae was studied in a novel whey-based culture media. Spore yield and viability were determined for two B. bassiana (GHA-726 and CA-603) and two M. anisopliae (CA-1 and IMI 330189) isolates following production in three whey-based systems: solid, liquid, and a diphasic production system. Our study indicated that whey permeate can be used effectively for production of spores of entomopathogenic fungi. However, spore yield and viability were significantly influenced by fungal isolate, whey concentration, and the type of production process used. Under the conditions defined in the present study, spore yields ranging from 1.3 × 10⁹–10 × 10¹¹ spores l⁻¹ of whey medium could be obtained depending on the strain and production process used. Our study revealed that spores produced by all strains in whey-based solid and liquid media showed between 73–99 % viability; germination rates were comparable with those obtained using the standard SDA medium. In the two-stage production process, the viabilities of conidia produced by GHA-726, CA-603, and CA-1 were 35–86, 32–98, and 6–29 %, respectively; viability was correlated with whey concentration and isolates. Whey permeate can be used as a growth substrate for mass production of biocontrol fungi. We hypothesize that spore yield and viability could be improved by careful selection of whey content in the medium, incorporation of critical additives and optimization of culture conditions.