Interactions Among the Aphid Diuraphis noxia , the Entomopathogenic Fungus Paecilomyces fumosoroseus and the Coccinellid Hippodamia convergens

Paecilomyces fumosoroseus (Wize) Brown & Smith is under development as a mycoinsecticide for control of the Russian wheat aphid, Diuraphis noxia Kurdjumov. Interactions with other natural enemies within the agro-ecosystem, such as the coccinellid Hippodamia convergens Guerin, require evaluation before its potential can be realized. In laboratory bioassays H. convergens adults were sprayed with suspensions of P. fumosoroseus conidia at different concentrations (including potential field rates) and mortality assessed. Although a proportion of coccinellids succumbed to infection (the greatest proportion was 22% when the ladybirds had suffered stress) it is unlikely that they would be at risk from infection as a direct result of a spray application unless there were prolonged periods of high humidity or the coccinellids were stressed. When provided with uninfected or P. fumosoroseus -infected D. noxia cadavers as prey, coccinellids consumed more uninfected aphids. The predators never consumed aphid cadavers from which the fungus was erupting or sporulating. Hippodamia convergens is, therefore, unlikely to be a significant intraguild predator of P. fumosoroseus . Predators contaminated with conidia of P. fumosoroseus using different methods (sprayed coccinellids, coccinellids foraging on sprayed aphids, and those foraging in the presence of sporulating D. noxia cadavers) were able to transfer conidia to healthy D. noxia populations and initiate infection in a proportion of those aphids. The proportion of aphids becoming infected was greatest when the coccinellids became contaminated when foraging amongst sporulating cadavers. Some coccinellids also succumbed to infection under these conditions.     

Modelling the Persistence of Quiescent Conidia of the Entomopathogenic Hyphomycete Paecilomyces fumosoroseus Exposed to Solar Radiation

Persistence of conidia of the entomopathogenic fungus Paecilomyces fumosoroseus exposed to artificial and solar radiation at a constant temperature was studied by monitoring the ability to germinate and to form colonies (colony - forming units , CFUs) . The photic effect of radiation on each of these variables was modelled by a decreasing function of UVB irradiation ( in J m 2) . Germination ability was represented by a logistic function and viability (log CFU) by an infinitely decreasing function . Experiments carried out under artificial conditions , at three different UVB irradiances ( from 0 . 3 to 1 . 6 W m 2) , similar to those observed in nature , confirmed the adequacy of the predictor variable and of the functions chosen for describing these data . The proposed models appeared to be irradiance independent . Under solar radiation , the models were able to describe data collected on three different summer days in France (48 o 51 N , 2 o 06 E) . However , it took a greater amount of solar UVB radiation to produce the same effect as that achieved indoors . This could be explained by differences in radiation spectra . For each model , one set of parameters was sufficient for representing all three sets of data: this constitutes an initial validation of the models proposed .     

Ovicidal and Larvicidal Activity of Conidia and Blastospores of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) Against Bemisia argentifolii (Homoptera: Aleyrodidae) with a Description of a Bioassay System Allowing Prolonged Survival of Control Insects

Fungi are the only effective entomopathogens of members of the Aleyrodidae and other homopterans because of the piercing and sucking feeding strategy of these insects. The laboratory assessment of the entomopathogenic activity of fungi often requires a prolonged period of observation. Leaf quality can be the limiting factor in bioassays of fungi against whiteflies that require longer observation periods or those that require conditions that are as close to natural ones as possible. A bioassay system is described that utilizes rooted cabbage leaves infested with the highly polyphagous whitefly, Bemisia argentifolii . Using this method, discriminating dosages of aerial conidia and blastospores of two isolates of Paecilomyces fumosoroseus (Pfr) were bioassayed against eggs and nymphs of B. argentifolii . Low, but significant, mortality (10-20%) of eggs was observed 14 days after exposure to 3.8 104 blastospores/cm2 for the Pfr 97 and European Biological Control Laboratory (EBCL) Pfr 42 isolates. Additionally, the majority of crawlers that had hatched from treated eggs died on the surface of the leaves. Exposure of early second-instar nymphs of B. argentifolii to 3.8 103 conidia or blastospores/cm2 of Pfr 97 resulted in mortalities of 27 and 77% respectively. Identical dosages of conidia and blastospores of the Pfr 42 isolate resulted in mortalities of 59 and 68% respectively. The bioassay method described enables the comparative evaluation of entomopathogenic fungi against whiteflies under diverse biotic and abiotic conditions.     

Impact of carbon and nitrogen nutrition on the quality, yield and composition of blastospores of the bioinsecticidal fungus Paecilomyces fumosoroseus

The impact of growing cultures of Paecilomyces fumosoroseus in liquid media containing four combinations of glucose and casamino acids (8 g l^–1 or 80 g l^–1 glucose, 1.32 g l^–1 or 13.2 g l^–1 casamino acids) was evaluated, based on blastospore production, germination rate, viability after freeze-drying and short-term storage stability. When blastospores were produced using a high casamino acid concentration, blastospore yields and germination rates were significantly higher (13.2–18.5×10⁷ blastospores ml^–1, 50–60% germination after 4 h), compared to cultures grown in media containing lower casamino acid concentrations (0.4–2.3×10⁷ blastospores ml^–1, 10–20% germination after 4 h). Chemical analyses of blastospore composition showed that accelerated blastospore germination may be related to increased proteinaceous reserves rather than to glycogen or lipid accumulation. Tolerance to freeze-drying by blastospores suspended in spent medium was enhanced by a high initial casamino acid concentration in the culture medium (75% survival) and by the residual glucose concentrations in the spent medium. Under the conditions of this study, the storage stability of blastospores of P. fumosoroseus was unaffected by the nutritional condition in which they were produced.     

腺苷蛋氨酸发酵条件及发酵培养基的优化

腺苷蛋氨酸具有转甲基、转硫和转氨丙基等重要生理作用 ,已成为治疗疾病的重要药物。研究了腺苷蛋氨酸发酵条件及发酵培养基的优化。结果表明 :发酵培养基的最适初始pH值为5.0 ;最佳发酵温度为 30℃ ;最适底物浓度为 1 % ;8%蔗糖为最佳碳源 ;0.5 %的NH4NO3 为最佳氮源 ;无机离子的最佳组合为 0.01 %MgSO4·7H2 O、0.03%CaCl2 、0.04%FeSO4·7H2 O和 0.01%LiCl。     

Isolation and characterization of microsatellite loci from the entomopathogenic hyphomycete,Paecilomyces fumosoroseus

Nine microsatellite markers were isolated from the entomopathogenic haploid fungus Paecilomyces fumosoroseus. Genetic diversity was assessed in 26 P. fumosoroseus isolates originated from the whitefly Bemisia tabaci collected in various geoclimatic areas. Eight loci were polymorphic with an observed number of alleles ranging from two to six. The loci differentiated some isolates and group of isolates according to their geographical location, showing promise for the study of gene flow. All loci failed to give clear amplifications in P. fumosoroseus isolates from hosts other than B. tabaci. These microsatellite markers provide powerful tools for ecological, epidemiological, and population genetic studies.     

Comparison of air-drying methods for evaluating the desiccation tolerance of liquid culture-produced blastospores of Paecilomyces fumosoroseus

Various drying methods were tested to identify a standard procedure for evaluating the desiccation tolerance of liquid culture-produced blastospores of Paecilomyces fumosoroseus. Since our work is focused on optimizing fermentation conditions for the production of P. fumosoroseus, the criteria for selecting a drying method included ease of use, moderate spore survival after drying and limited variation in spore survival. Three air-drying methods were tested: P. fumosoroseus blastospores mixed with silica gel, with sand, or with diatomaceous earth. Humidity controlled drying was used in the diatomaceous earth drying method. Blastospore survivals after drying were 19% (C.V. range, 32 to 45%), 82% (C.V. range, 26 to 43%), and 2% (C.V. range 32 to 50%) for the silica gel, sand, and diatomaceous earth methods, respectively. Blastospores dried using the silica gel and sand methods had been rinsed in 0.7 m polyethylene glycol before drying and rehydrated in the same solution for determination of survival. The variation observed within each method was similar. The silica gel drying method was selected as most appropriate for our studies based on moderate blastospore survival (19%) and ease of use.     

Liquid-culture production of blastospores of the bioinsecticidal fungus<Emphasis Type="Italic"> Paecilomyces fumosoroseus</Emphasis> using portable fermentation equipment

The production of fungal spores using on-site, non-sterile, portable fermentation equipment is technically constrained. Very little information is available on the production requirements, such as medium concentration, inoculum stabilization, required fermentation times, and maintenance of axenic growth. In this study, we developed a two-part, liquid concentrate of the production medium that remains stable and soluble at room temperature. We also examined inoculum stability and showed that freeze- or air-dried blastospore preparations were stable for 7 days after rehydration when stored at 4 °C. The use of a low-pH (pH 4), relatively rich complex medium provided a growth environment deleterious to bacterial growth yet conducive to rapid sporulation by Paecilomyces fumosoroseus. High concentrations of blastospores (7.9×10⁸/ml) of P. fumosoroseus were produced in a 40-h fermentation with very low levels of bacterial contamination when the fermentor was charged with a blastospore production medium with a starting pH of 4 and inoculated with blastospore concentrations greater than 1×10⁶ spores/ml. These studies demonstrate that the use of disinfected, portable fermentation equipment has potential for on-site production of high concentrations of blastospores of the bioinsecticidal fungus P. fumosoroseus.     

Production of a Laccase and Decrease of the Phenolic Content in Canola Meal during the Growth of the Fungus Pleurotus ostreatus in Solid State Fermentation Processes

Solid state fermentation of canola meal was carried out with the fungus Pleurotus ostreatus DAOM 197961, which is a producer of laccase. The aim of this study was to examine the effects of moisture content, inoculum size, homogenisation of inoculum and particle size of canola meal on the growth of the fungus, the production of a laccase and the decrease of the content of sinapic acid esters (SAE) in a solid state process. The results showed that the optimum moisture content, which was varied in the media between 50% and 75%, for the growth and enzyme production was 60%. The initial rate of SAE content decrease was faster in the media with 70% and 75% moisture than in those with lower moisture levels. In the study of the effects of inoculum concentration in the range of 1.1 mg to 5.5 mg/g of the medium, it was found that larger amounts of biomass and enzyme were produced in the media with inoculum concentrations from 1.1 mg to 3.3 mg/g of the medium than in the media with a higher inoculum concentration. The final and approximately the same concentrations of SAE were reached at the same time regardless of the inoculum concentration. Considering that the fungus formed pellets under the conditions at which it was grown during the inoculum preparation, it was necessary to break them by homogenisation prior to their utilisation as an inoculum. The homogenisation was carried out during a period between 15s and 200s. Although higher biomass concentrations and enzyme activities were obtained in the media which were inoculated with the inoculum homogenised for 15s and 30s, the maximum enzyme activities and biomass concentrations were reached in the media inoculated with the inoculum, which was homogenised for 120s and 200s. The time of inoculum homogenisation did not influence the kinetics of the SAE decrease. When the effects of the particle size of canola meal on the process were studied, it was found that larger particles of the meal in the solid media were more favourable for the production of the biomass and enzyme, and for a faster decrease of the SAE content than those of smaller sizes. From the obtained results it can be concluded that the tested variables have a significant influence on the growth of the fungus Pleurotus ostreatus DAOM 197961, the production of laccase and the decrease of the SAE content in canola meal. The data could be useful for the development of a solid state process for the production of laccase and for the decrease of the phenolics content in canola meal.     

Interactions of Paecilomyces lilacinus strain 251 with the mycorrhizal fungus Glomus intraradices: Implications for Meloidogyne incognita control on tomato

The interactions of Paecilomyces lilacinus strain 251 with the arbuscular mycorrhizal fungus Glomus intraradices and their significance for the control of Meloidogyne incognita on tomato were investigated in greenhouse experiments. Application of P. lilacinus had no effect on the frequency and intensity of tomato root colonization by G. intraradices. Likewise, the decline of the nematophagous fungus densities after single application in soil was not affected by the presence of the mycorrhizal fungus. Single application of P. lilacinus, as pre-planting soil treatment, resulted in significant reduction of nematode damage. In contrast, mycorrhizal inoculation did not provide sufficient biocontrol. Combined application of the two agents did not enhance root protection compared to single treatments. Double treatment of mycorrhized seedlings with P. lilacinus, as seedling drench and pre-planting soil treatment, 4 and 1 week before transplanting, respectively, resulted in the highest reduction of the nematode damage. These results indicate the potential of the commercial P. lilacinus strain 251 and mycorrhiza for integration in nematode control strategies.     

不同发酵方式和保存方法对3种生防菌活菌量的影响

为明确3株优良生防菌SC11、153、FO47在不同发酵方法和保存条件下活菌量变化规律,采用活菌平板计数法,测定3种生防菌12个月内活菌量变化及3种生防菌粉剂发酵初期和12月保存期后对茄子黄萎病的温室盆栽防效。结果表明,SC11、 153和FO47菌粉于4 ℃密封保存12个月后活菌量与其初始活菌量差异不显著（P<0.05）;FO47菌粉在4 ℃保存12个月后活菌量高于初始活菌量（P<0.05）;3种生防菌发酵液初始活菌量较菌粉低1～2个数量级,在保存期60 d内活菌量急剧下降,第6个月时接近于0。3种生防菌粉存放12个月后对茄子黄萎病仍保持较高的抑菌活性。说明,固体发酵菌粉可以得到较高数量级的初始活菌量,3种生防菌菌粉4 ℃密封保存12个月后活菌量及抑菌活性不变,且FO47菌粉活菌量略有上升;发酵液不利于生防菌的长期保存。     

Fermentation Kinetics of Media Optimization for the Production of Alpha Amylase by a New Isolate of Aspergillus Oryzae

The starch-degrading enzyme‘α-amylase’is widelydistributedin nature .This extracellular enzyme randomlyhydrolyzesα1~4 glucosidic linkage throughout the starchmolecule in an endo-fashion producing oligosaccharidesand monosaccharides including maltose ,…     

The effect of selected allelochemicals on germination of conidia and blastospores and mycelial growth of the entomopathogenic fungus,Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes)

Selected allelochemicals that protect plants from invasion by plant pathogenic fungi were investigated for their activity against the entomopathogenic fungus, Paecilomyces fumosoroseus. The alkaloids tomatine, solanine, and camptothecin; the furanocoumarin, xanthotoxin; and the phenolic, tannic acid were tested for their effects on germination of conidia and blastospores and growth of mycelia. The LC50 values (corresponding to 50% inhibition of germination) for tomatine, solanine, camptothecin, xanthotoxin and tannic acid were 51.6, 95.9, 55.9, 83.0 and 72.8 mg/l respectively. When blastospores were placed on media containing a concentration of the individual allelochemicals that inhibit germination in approximately 50% of conidia, all but blastospores on tomatine had significantly less germination than did aerial conidia. Growth rates of mycelia were slowest in the camptothecin medium, followed by those of tomatine and xanthotoxin and were not significantly different from controls in the media containing solanine and tannic acid. A multitude of biotic and abiotic factors are responsible for specificity and degree of pathogenicity of entomopathogens. The effect of crop plant chemistry on the efficacy of entomopathogens should be quantified further in order to maximize their potential when used concomitantly with resistant plant varieties. This revised version was published online in June 2006 with corrections to the Cover Date.     

Production of microsclerotia of the fungal entomopathogen Metarhizium anisopliae and their potential for use as a biocontrol agent for soil-inhabiting insects

Microsclerotia (MS), overwintering structures produced by many plant pathogenic fungi, have not been described for Metarhizium anisopliae. Three strains of M. anisopliae – F52, TM109, and MA1200 – formed MS in shake flask cultures using media with varying carbon concentrations and carbon-to-nitrogen (C:N) ratios. Under the conditions of this study, all strains produced MS, compact hyphal aggregates that become pigmented with culture age, in addition to more typical blastospores and mycelia. While all strains formed desiccation tolerant MS, highest concentrations (2.7–2.9 × 10⁸ L⁻¹ liquid medium) were produced in rich media with C:N ratios of 30:1 and 50:1 by strain F52. All three strains of M. anisopliae produced similar biomass concentrations when media and growth time were compared. Strain MA1200 produced higher concentrations of blastospores than the other two strains of M. anisopliae with highest blastospore concentrations (1.6 and 4.2 × 10⁸ blastospores ml⁻¹ on days 4 and 8, respectively) in media with the highest carbon and nitrogen concentrations. Microsclerotial preparations of M. anisopliae containing diatomaceous earth survived air-drying (to <5 % moisture) with no significant loss in viability. Rehydration and incubation of air-dried MS granules on water agar plates resulted in hyphal germination and sporogenic germination to produce high concentrations of conidia. Bioassays using soil-incorporated, air-dried MS preparations resulted in significant infection and mortality in larvae of the sugar beet root maggot, Tetanops myopaeformis. This is the first report of the production of sclerotial bodies by M. anisopliae and provides a novel approach for the control of soil-dwelling insects with this entomopathogenic fungus.     

Trials of Beauveria bassiana, Paecilomyces fumosoroseus and imidacloprid for management of Trialeurodes vaporariorum (Homoptera: Aleyrodidae) on greenhouse grown lettuce

Mineral oil-based emulsifiable preparations of Beauveria bassiana (Bb) and Paecilomyces fumosoroseus (Pfr) conidia were separately applied alone or together with low rates of imidacloprid 10% WP at 4.7% (Im 1), 14.0% (Im 2), and 23.3% (Im 3) of its recommended application rate, respectively, against the greenhouse whitefly, Trialeurodes vaporariorum, on lettuce grown in the greenhouse. Besides eight fungal treatments, the three low application rates of imidacloprid in the oil-based carrier and a blank control (CK) were also included as treatments of the trials conducted in 2002 and 2003. For the 12 treatments of each trial with three replicates, 1,000-fold aqueous dilutions were sprayed twice on transplanted lettuce at a 15-day interval at a rate of ∼1.43×10¹³ conidia ha^-1 for each fungal treatment or at one of the low rates of imidacloprid using a backpack hand-operated hydraulic sprayer. Based on whitefly densities, mortalities, relative efficacies and percent density declines estimated from whitefly counts made at 5-day intervals, all B. bassiana and P. fumosoroseus sprays were highly effective against T. vaporariorum compared to CK and Im 1-3 in both trials. In trial 1, the estimates of whitefly density decline and relative efficacy ranged from 44 and 72% (Bb) to 79 and 90% (Pfr+Im 2-3) on day 10 after the first spray and exceeded 94% for all fungal treatments 10 days after the second spray. Similar trends in whitefly control were also achieved in the corresponding treatments of trial 2. A more desirable and faster control resulted from fungal sprays containing more imidacloprid, but none of the three low imidacoprid rates alone suppressed the whitefly population more effectively than any fungal treatment despite a varying degree of efficacy. Moreover, P. fumosoroseus tended to be more effective against T. vaporariorum than B. bassiana when applied alone or together with the same low rate of imidacloprid but the difference in whitefly control eventually achieved was not significant between the two fungal agents. Thus, the emulsifiable preparations of both fungal agents can be considered as alternatives for whitefly management and for a slightly faster control can be applied together with imidacloprid at around 15% of its common application rate. An economic balance between the efficacy of whitefly control and the ease and cost of conidial production is needed when both fungi are incorporated into whitefly management.     

菜青虫感染玫烟色拟青霉后血淋巴蛋白质含量及几种保护酶活力的变化

对玫烟色拟青霉Paecilomyces fumosoroseus侵染3、4龄菜青虫Pieris rapae后,其血淋巴中蛋白质含量、体内保护酶及谷胱甘肽S-转移酶活力进行了研究。结果表明,感病的3、4龄菜青虫血淋巴中蛋白质含量明显低于同期未感染的幼虫;感病虫体内超氧化物歧化酶、过氧化氢酶和过氧化物酶的活力发生了不同程度的改变,其中对3龄菜青虫体内酶活力的影响比4龄幼虫大。此外被侵染的3、4龄菜青虫体内谷胱甘肽S-转移酶活力在感病前期显著高于同期未感染的菜青虫,而在感病后期明显低于同期未感染的菜青虫。     

Influence of formulation additives on the desiccation tolerance and storage stability of blastospores of the entomopathogenic fungus Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes)

Blastospores of the entomopathogenic fungus Paecilomyces fumosoroseus were formulated with 10% lactose/1% bovine serum albumin (BSA) or various compositions of Fantesk™, a starch-oil composite prepared by jet-cooking an aqueous dispersion of starch and oil. Storage stability studies with wet blastospore formulations showed that maximum blastospore survival was achieved during low-temperature storage at -20°C with lactose/BSA formulations or starch-oil formulations supplemented with sucrose, zein protein, and whole milk. Under conditions of wet storage at -20°C, the addition of whole milk to starch-oil formulations significantly improved blastospore stability while the addition of sucrose or zein protein had no effect. In freeze-drying studies, no significant differences were seen in blastospore desiccation tolerance or in stability during storage at either 4 or -20°C when blastospores of P. fumosoroseus were formulated with lactose/BSA or starch-oil formulations with sucrose, zein protein, and whole milk. Freeze-dried blastospore formulations stored at 4°C showed no loss in blastospore viability after 3 months storage and blastospore formulations stored at -20°C showed no loss in viability during the entire 12-month study. For freeze-dried, starch-oil formulations, sucrose was shown to improve blastospore survival during the freeze-drying process. The addition of whole milk to starch-oil formulations significantly improved the stability of freeze-dried blastospores stored at 4°C. Compared to unformulated blastospore suspensions that showed blastospore settling after 30 min, suspensions of blastospores formulated with lactose/BSA or starch-oil composites remained stable for up to 2 h after mixing.     

Effect of various liquid culture media on morphology,growth, propagule production,and pathogenic activity to Bemisia argentifolii of the entomopathogenic Hyphomycete,Paecilomyces fumosoroseus

The entomopathogenic Hyphomycete Paecilomyces fumosoroseus was grown in five different liquid media, which have been developed for mass production of Beauveria spp. or P. fumosoroseus. Production was followed for 96 h by measuring both biomass and concentration of propagules. Maximal biomass was obtained with two media, Jackson and Catroux media (40–60 mg ml-1 suspension produced after 42 h incubation), where the exponential phase of growth began earlier than in the other media. While high concentrations of propagules (1.4–5.5 × 108 propagules ml-1) were produced in three media (Jackson, Paris, and Catroux media) after 48–72 h incubation, production of propagules was lower in the two other media, containing maltose as carbon source (Goral and Kondryatiev media) with 0.4–3.7 × 107 propagules ml-1 after 96 h incubation. P. fumosoroseus produced oblong blastospores in the three most productive media and conidiospore-like (ovoid to subspherical) propagules in the two other media. Infection potential of produced propagules was tested on the silverleaf whitefly ( Bemisia argentifolii). Whiteflies were sprayed as 2nd instars with P. fumosoroseus propagules produced in the five liquid media (1.9 × 103 and 1.9 × 104 propagules cm-2). All the media produced propagules that were infectious for larvae. With the lower dosage, mortality rates were significantly lower with propagules produced in one of the two least productive media (57%) (in the Kondryatiev medium) compared to those obtained with the three most productive media (>90%). However, when whiteflies were treated with the higher dosage, mortality rates (91–99%) between media were not significantly different. This revised version was published online in June 2006 with corrections to the Cover Date.     

Fermentation Kinetics of Media Optimization for the Production of Alpha Amylase by a New Isolate of Aspergillus Oryzae

The present study is concerned with the isolation and screening of different strains of Aspergillus oryzae for the production of alpha amylase. Ninety strains were isolated from soil and tested for the production of alpha amylase in shake flasks. Of all the strains tested, Aspergillus oryzae GCB-32 and Aspergillus oryzae GCB-35 gave maximum production of alpha amylase. Different culture media were screened for the production of alpha amylase by these two strains. M1 medium containing starch, yeast extract, NH₄Cl, MgSO₄·7H₂O and CaCl₂ gave the maximum production of alpha amylase by both the strains Aspergillus oryzae GCB-32 and Aspergillus oryzae GCB-35.Kinetic analysis revealed that the values of product yield coefficient(Y_p/x) and specific product yield coefficient(q_p) were found highly significant(p≤0.05) when medium M1 was used for the enzyme production.