Lilacinus Strain Research Articles

SELECTION OF INDIGENOUS STRAINS (Paecilomyces lilacinus) PARASITIZE Meloidogyne spp. ISOLATED FROM BA RIA – VUNG TAU PROVINCE

Twenty two Paecilomyces lilacinus strains were isolated from forest soils and black pepper rhizospheres in Ba Ria –Vung Tau Province. The ability to degrade chitin of PB 3.3, PB 2.9, QT2, and QT5 strains was high. The ability to degrade casein of PB 1.3, PB 2.10, KL5, and KL6 strains was efficient. And then, these strains were parasitized females and egg masses of Meloidogyne spp. in vitro. In female parasitism test, the rates of parasitizing female nematodes reached more than 50 % after treating for 2 days. Four strains of PB 2.10, PB 1.3, KL6 and QT5 belonged to the first group achieved the highest parasitic (> 90 %) effects on female after 3 days of incubation. In egg masses parasitism test, three strains of PB 1.3, PB 2.10 and QT5 exhibited 83.33 %, 75 % and 75 % parasitism on egg masses after 11 days of incubation. The rates of parasitizing female were higher than egg masses. Three selected strains from the experiments were PB 1.3, PB 2.10 and QT5.

Management of Root-knot Nematode (Meloidogyne incognita) on Pittosporum tobira Under Greenhouse, Field, and On-farm Conditions in Florida.

Root-knot nematodes are important pests of cut foliage crops in Florida. Currently, effective nematicides for control of these nematodes on cut foliage crops are lacking. Hence, research was conducted at the University of Florida to identify pesticides or biopesticides that could be used to manage these nematodes. The research comprised on-farm, field, and greenhouse trials. Nematicide treatments evaluated include commercial formulations of spirotetramat, furfural, and Purpureocillium lilacinum (=Paecilomyces lilacinus) strain 251. Treatment applications were made during the spring and fall seasons according to manufacturer's specifications. Efficacy was evaluated based on J2/100 cm3 of soil, J2/g of root, and crop yield (kg/plot). Unlike spirotetramat, which did not demonstrate any measurable effects on Meloidogyne incognita J2 in the soil, furfural and P. lilacinum were marginally effective in reducing the population density of M. incognita on Pittosporum tobira. However, nematode reduction did not affect yield significantly. Although furfural and P. lilacinum have some potential for management of M. incognita on cut foliage crops, their use as a lone management option would likely not provide the needed level of control. Early treatment application following infestation provided greater J2 suppression compared to late application, suggesting the need for growers to avoid infested fields.

Effect of plant resistance and BioAct WG (Purpureocillium lilacinum strain 251) on Meloidogyne incognita in a tomato-cucumber rotation in a greenhouse.

The effectiveness of combining resistant tomato with BioAct WG (Purpureocillium lilacinum strain 251, Pl251) against Meloidogyne incognita was assessed in a tomato-cucumber rotation in a greenhouse over 2 years. Additionally, the enzymatic activity of the fungus, the percentage of fungal egg and juvenile parasitism, cardinal temperatures and the effect of water potential on mycelial growth and the soil receptivity to Pl251 were determined in vitro. Plant resistance was the only factor that suppressed nematode and crop yield losses. Percentage of egg parasitism in plots treated with BioAct WG was less than 2.6%. However, under in vitro conditions, Pl251 showed protease, lipase and chitinase activities and parasitised 94.5% of eggs, but no juveniles. Cardinal temperatures were 14.2, 24-26 and 35.4 °C. The maximum Pl251 mycelial growth was at -0.25 MPa and 25 °C. Soil temperatures and water potential in the greenhouse were in the range of the fungus. However, soil receptivity was lower in greenhouse soil, irrespective of sterilisation, than in sterilised sand. Plant resistance was the only factor able to suppress nematode densities, disease severity and yield losses, and to protect the following cucumber crop. Environmental factors involved in soil receptivity could have negatively affected fungus effectiveness. © 2016 Society of Chemical Industry.

Genome and Transcriptome Sequences Reveal the Specific Parasitism of the Nematophagous Purpureocillium lilacinum 36-1.

Purpureocillium lilacinum is a promising nematophagous ascomycete able to adapt diverse environments and it is also an opportunistic fungus that infects humans. A microbial inoculant of P. lilacinum has been registered to control plant parasitic nematodes. However, the molecular mechanism of the toxicological processes is still unclear because of the relatively few reports on the subject. In this study, using Illumina paired-end sequencing, the draft genome sequence and the transcriptome of P. lilacinum strain 36-1 infecting nematode-eggs were determined. Whole genome alignment indicated that P. lilacinum 36-1 possessed a more dynamic genome in comparison with P. lilacinum India strain. Moreover, a phylogenetic analysis showed that the P. lilacinum 36-1 had a closer relation to entomophagous fungi. The protein-coding genes in P. lilacinum 36-1 occurred much more frequently than they did in other fungi, which was a result of the depletion of repeat-induced point mutations (RIP). Comparative genome and transcriptome analyses revealed the genes that were involved in pathogenicity, particularly in the recognition, adhesion of nematode-eggs, downstream signal transduction pathways and hydrolase genes. By contrast, certain numbers of cellulose and xylan degradation genes and a lack of polysaccharide lyase genes showed the potential of P. lilacinum 36-1 as an endophyte. Notably, the expression of appressorium-formation and antioxidants-related genes exhibited similar infection patterns in P. lilacinum strain 36-1 to those of the model entomophagous fungi Metarhizium spp. These results uncovered the specific parasitism of P. lilacinum and presented the genes responsible for the infection of nematode-eggs.

Liquid culture production of microsclerotia of Purpureocillium lilacinum for use as bionematicide

The production of microsclerotia by Purpureocillium lilacinum in liquid culture for use as a biocontrol agent for management of root-knot nematode, Meloidogyne incognita, has not been described. To investigate the potential for microsclerotia production, P. lilacinum strain CQPL01 was cultured in liquid media containing various concentrations of ferrous sulphate. Under these conditions mycelia began to form microsclerotia. The maximum yield (11.8 × 104 microsclerotia ml−1) was obtained in medium containing 0.2 g l−1 ferrous sulphate and the greatest production of conidia (1.3 × 108 conidia g−1) was obtained by the culture of air-dried microsclerotia in aqueous agar medium. Subsequently, the viability of microsclerotia, including stress resistance, storage stability and pathogenicity against M. incognita, was investigated. The microsclerotia exhibited excellent nematophagous ability and greater thermotolerance and UV-B radiation tolerance compared to conidia. These results suggested that microsclerotia propagules might be superior to the use of conidia in P. lilacinum biocontrol products.

In vitro effect of Purpureocillium lilacinum (Thom) Luangsa-Ard et al. and Pochonia chlamydosporia var. catenulata (Kamyschko ex Barron & Onions) Zare & Gams on the root -knot nematodes [Meloidogyne incognita (Kofoid & White) chitwood and Meloidogy ...

IN VITRO EFFECT OF Purpureocillium lilacinum (Thom) Luangsa-Ard et al. AND Pochonia chlamydosporia var. catenulata (Kamyschko ex Barron & Onions) Zare & Gams ON THE ROOT-KNOT NEMATODES [P. chlamydosporia (Kofoid & White) Chitwood AND Meloidogy nemayaguensis Rammh & Hirschmann]
 Purpureocillium lilacinum strain PL-11 and Pochonia chlamydosporia strain JL-1 fungal strains, are a biological alternative to reduce plant parasitic nematodes on the roots of plants. The objective of this research was to determine the most effective concentration of P. lilacinum strain PL-11 and P. chlamydosporia strain JL-1, for the management of root-knot nematode (Meloidogyne spp.). In the Plant Pathology laboratory, at University of Caldas, in a completely randomized design, 1 mL of P. lilacinum (1 x 109 spores / mL) were added to 32 bacteriological Petri dishes with agar; subsequently, 16 of them were inoculated with a 30 mL suspension containing 10 eggs of P. chlamydosporia and Meloidogyne mayaguensis and, the other 16, were inoculated with a 30 mL suspension containing 10 juveniles (J2) of the two Meloidogyne species. Fungal infection of eggs and mortality of juveniles (J2) of the two species of Meloidogyne were evaluated at 24, 72, 120 and 168 h. The same procedure was performed with P. chlamydosporia, the combination P. lilacinum and P. chlamydosporia, P. lilacinum and P. chlamydosporia in combination with Carbofuran at concentrations between 1 x 103 and 1 x 109 spores / mL. The positive and negative controls were Carbofuran and water, respectively. Results demonstrated that mixing P. lilacinum and P. chlamydosporia (1 x 106 spores / L) in combination with Carbofuran, and the mixture P. lilacinum and P. chlamydosporia (1 x 108 spores / mL), caused the highest infections on eggs with 85% and 80%, respectively, and caused the highest mortality of juvenile (J2) of M. incognita and M. mayaguensis with 93% and 75%, respectively, compared to the water treated group, at 168 h.

A method to evaluate relative ovicidal effects of soil microfungi on thick-shelled eggs of animal-parasitic nematodes

Thick-shelled eggs of animal-parasitic ascarid nematodes can survive and remain infective in the environment for years. The present study evaluated a simple in vitro method and evaluation scheme to assess the relative effect of two species of soil microfungi, Pochonia chlamydosporia Biotype 10 and Purpureocillium lilacinum Strain 251 (Ascomycota: Hypocreales), on the development and survival of eggs of faecal origin of three ascarid species, Ascaridia galli (chicken roundworm), Toxocara canis (canine roundworm) and Ascaris suum (pig roundworm). Ascarid eggs were embryonated on water agar with or without a fungus, and the resulting viability of the eggs was evaluated on days 7, 14, 21, 28, 35 and 42 post exposure (pe) by observing eggs in situ. On days 7–42 pe, P. chlamydosporia had reduced the viability of A. galli and T. canis eggs by 64–86% and 26–67%. Corresponding reductions for P. lilacinum Strain 251 were only 15–29% and 4–28%. In contrast, A. suum eggs were extremely resistant to both fungi (2–4% reduction). The differences in results are likely due to different morphologies and chemistry of the egg shell of the three ascarid species. The current in vitro method and evaluation criteria allow for a simple, repeatable and non-invasive evaluation of the ovicidal effects of microfungi. This study demonstrates that P. chlamydosporia Biotype 10 may be utilised as a biocontrol agent to reduce A. galli and T. canis egg contamination of the environment.

The entomopathogenic fungal endophytes Purpureocillium lilacinum (formerly Paecilomyces lilacinus) and Beauveria bassiana negatively affect cotton aphid reproduction under both greenhouse and field conditions.

The effects of two entomopathogenic fungal endophytes, Beauveria bassiana and Purpureocillium lilacinum (formerly Paecilomyces lilacinus), were assessed on the reproduction of cotton aphid, Aphis gossypii Glover (Homoptera:Aphididae), through in planta feeding trials. In replicate greenhouse and field trials, cotton plants (Gossypium hirsutum) were inoculated as seed treatments with two concentrations of B. bassiana or P. lilacinum conidia. Positive colonization of cotton by the endophytes was confirmed through potato dextrose agar (PDA) media plating and PCR analysis. Inoculation and colonization of cotton by either B. bassiana or P. lilacinum negatively affected aphid reproduction over periods of seven and 14 days in a series of greenhouse trials. Field trials were conducted in the summers of 2012 and 2013 in which cotton plants inoculated as seed treatments with B. bassiana and P. lilacinum were exposed to cotton aphids for 14 days. There was a significant overall effect of endophyte treatment on the number of cotton aphids per plant. Plants inoculated with B. bassiana had significantly lower numbers of aphids across both years. The number of aphids on plants inoculated with P. lilacinum exhibited a similar, but non-significant, reduction in numbers relative to control plants. We also tested the pathogenicity of both P. lilacinum and B. bassiana strains used in the experiments against cotton aphids in a survival experiment where 60% and 57% of treated aphids, respectively, died from infection over seven days versus 10% mortality among control insects. Our results demonstrate (i) the successful establishment of P. lilacinum and B. bassiana as endophytes in cotton via seed inoculation, (ii) subsequent negative effects of the presence of both target endophytes on cotton aphid reproduction using whole plant assays, and (iii) that the P. lilacinum strain used is both endophytic and pathogenic to cotton aphids. Our results illustrate the potential of using these endophytes for the biological control of aphids and other herbivores under greenhouse and field conditions.

Improving suppression of Meloidogyne spp. by Purpureocillium lilacinum strain 251

The fungus Purpureocillium lilacinum (syn. Paecilomyces lilacinus) is marketed for control of plant-parasitic nematodes in several countries. Our objectives in this study were to determine whether suppression of Meloidogyne spp. by P. lilacinum strain 251 was affected by the crop plant and whether growing winter cover crops such as rye and crimson clover would improve suppression of M. incognita on cotton by the fungus. All experiments were conducted in a glasshouse using non-sterilised field soil. To determine the relative efficacy of P. lilacinum on cotton (Gossypium hirsutum), peanut (Arachis hypogaea) and maize (Zea mays), four concentrations of P. lilacinum (NemOut™) were applied in furrow: 336, 252, 168 and 0 g ha−1. Although the fungus reduced numbers of eggs of Meloidogyne spp. on all crops, percentage suppression was lower on maize than on cotton and peanut at all inoculum levels of P. lilacinum. When rye and crimson clover were grown in pots for 30 days and then killed with a herbicide prior to applying P. lilacinum and M. incognita and planting cotton, the fungus failed to suppress numbers of nematode eggs when the surface residues of the cover crops were removed. However, when the residues were left on the soil surface, percentage suppression (49% for clover and 63% for rye) was greater than when the soil was left fallow (36%). The residues could have created conditions that were more conducive than bare soil to the fungus, such as lower soil temperatures and increase moisture retention.

Biodegradation of feather wastes and the purification and characterization of a concomitant keratinase from Paecilomyces lilacinus.

Paecilomyces lilacinus strain PL-HN-16 was found to have the ability to degrade feathers. During the degradation process, the broth initially turned as sticky as gelatin and then turned into fluid that means the feathers can be hydrolyzed completely. Keratinolytic protein (Ker) of aforementioned strain was purified using ammonium sulphate precipitation, HiTrap Butyl FF chromatography and Sephacryl S-200 gel filtration. The Ker of P. lilacinus PL-HN-16 had molecular mass of 33 kDa, the optimum pH 8.0 and temperature optimum at 40 degrees C. It used the soluble keratin as substrate. The enzyme showed high activity and stability over a wide range of pH (6.0 to 10.0) and temperature (300C to 600C) values but was completely inhibited by PMSF. Ker of P. lilacinus PL-HN-16 exhibited stability toward SDS. These promising properties make the enzyme a potential candidate for future applications in biotechnological processes as keratin hydrolysis and dehairing during leather processing.

Bio-pesticides: Harmful or harmless to ammonia oxidizing microorganisms? The case of a Paecilomyces lilacinus-based nematicide

Bio-pesticides are considered as low-risk compounds, a belief mainly based on their natural origin rather than on experimental evidence. Thus there is a need to explore the ecotoxicity of bio-pesticides and mostly their impact on soil microbes which is largely unknown. The effect of Quillajia saponaria plant extract (QLAgri®) and Paecilomyces lilacinus strain 251 (PL251, BIOACT®) on the microbial community was investigated comparatively to the synthetic nematicides oxamyl and fluensulfone. Particular attention was given to potential effects on ammonia-oxidizing bacteria (AOB) and archaea (AOA). No effect of QLAgri®, oxamyl and fluensulfone on the soil microbial community and AOB/AOA was observed. In contrast BIOACT® stimulated the growth of copiotrophic Gram negative bacteria and fungi as determined by phospholipid fatty acids (PLFA) analysis. Terminal restriction fragments length polymorphism (TRFLP) and qPCR analysis of the amoA gene showed a significant time-dependent inhibitory effect of BIOACT® on the abundance of AOB/AOA up to 20 days post application. Further qPCR analysis indicated that PL251 did not proliferate in soil. These results suggested the establishment of complex interactions between BIOACT® and AOB/AOA which were further explored. In a follow-up study BIOACT® and its co-formulants, glucose (78%) and skimmed milk powder (6%), both induced a transient inhibitory effect on potential nitrification and abundance of AOB/AOA, whereas no effect was seen when PL251 spores were used. Overall, our data suggest that the transient effect of BIOACT® on nitrifiers was the result of a competitive exclusion by copiotrophic microorganisms feeding on co-formulants rather than a direct toxicity effect.

Nematicidal efficacies of several organic and microbial fertilizers against Root-knot nematodes (Meloidogyne spp.) in organic tomato farming

This study was conducted to determine of the efficacy of some materials such as organic and microbial fertilizers and some plant extracts having nematicidal effects against Root-knot nematodes (Meloidogyne incognita and M. javanica) as a Biocontrol method in organic tomato (cv. Gokce) production. As the chemical control treatment using with the Fenamiphos (Nemacur® EC 400), garlic extracts (NemGuard®), biological control preparations containing the spores of Paecilomyces lilacinus strain 251 (Bioact® WG 400g), sesame oil (Nemax®), organic fertilizer (Agro-full Nemaflash®), the extracts of Quillaja saponaria (QLAgri® 35), thymus extracts (Bionem®), Neem oil extracts (NeemAzal®-T/S), and double combination of some of these materials were used in the trails. The experiments were conducted according to randomized block design with four replicates during the autumn (August-January) of two successive years (2010 and 2011). The population densities of the second stage juvenile of root knot nematode were evaluate to determine the effects of the treatments. Also, yield loses and gall scale of the plants were determined at the end of the trials. In 2010, the use of Bioact®+QLAgri® 35 (37.83%) and Nemax®+QLAgri® 35 (36.87%); in 2011, Nemax® (10.84%) and NemGuard® (9.62%) reduced the root galling caused by nematodes when compared to the control plants. In terms of tomato yield, in 2010 the use of Agro-full Nemaflash® (27.50%) and Nemax®+Bioact® (21.19%); in 2011 Bioact®+QLAgri® 35 (23.67%) and Nemax®+Bioact® (14.29%) increased yield significantly. Consequently the sesame oil (Nemax®) is alone or combined with usage of some other materials could be more effective to control M. incognita and M. javanica in organic tomato production

Generation of green fluorescent protein vector transformed Paecilomyces lilacinus Strains

Paecilomyces lilacinus is one of the most important biocontrol fungi and has been applied extensively for controlling root-knot nematodes. The protoplast/PEG/CaCl2 method was used to generate green fluorescent protein (GFP) transformants of two strains ofPaecilomyces lilacinus (strain 20-7 and 618). Two transformed strains were successfully generated and identified by fluorescence microscopy. Transformation was confirmed by recovery, cloning and sequencing of polymerase chain reaction (PCR) products and Southern blot analysis. Two stably transformed strains were isolated (20-7 and 618 strain). GFP transformants of Paecilomyces lilacinus provide useful resources for elucidating the mechanism of controlling root-knot nematodes. Key words: Paecilomyces lilacinus, green fluorescent protein, fluorescence expression, transformants.

Nematicidal and fertilizing effects of chicken manure, fresh and composted olive mill wastes on organic melon

Abstract The fertilizing and nematicidal effects of three organic amendments were evaluated in a pot experiment on melon plants infested by the root-knot nematode Meloidogyne incognita. A soil artificially infested with 4 eggs and juveniles/ ml soil of the nematode was amended with: a) virgin olive pomace (VOP); b) composted olive pomace (COP); c) chicken manure based fertilizer (CM) and d) chicken manure based fertilizer combined with the biological control agent Paecilomyces lilacinus strain 251, brand name BioAct WG (CMB). VOP was applied at doses of 11 (VOP-A), 22 (VOP-B) and 44 t/ha (VOP-C); COP at 4.5 (COP-A), 9 (COP-B) and 18 t/ha (COP-C); CM at 3 t/ha and CMB at 3 t/ha combined with 4 kg/ha of BioAct WG. Untreated soil was used as control. The treatments CM, CMB, VOP-B and COP-B were established on the basis of N requirement of melon plants (120 kg/ha) taking into account soil and amendments N availability. Two weeks later amendment application and nematode inoculation, the soil was poured in 4.8 l clay pots which were arranged in a greenhouse according to a randomized block design with ten replications for each treatment. A one-month old melon seedling (cv. Galia) was transplanted in each pot and organic farming management practices were used during the growing period. At the end of the experiment, 60 days after transplant, plants were uprooted and height, fresh and dry shoot and root weights were recorded. Root gall index, on the roots, caused by the nematode attack, was estimated according to a 0–5 scale. Final nematode population density and reproduction rate were also calculated for each pot. All data were subjected to statistical analysis of variance (ANOVA) and means compared according to Least Significant Difference’s Test. Nematode population and root infestation were significantly suppressed by the addition of all amendments, compared to untreated control. However, CM and CMB resulted in a total more suppressive effect and in a significantly higher plant growth in comparison to all the other treatments. A significant correlation was found between root gall index and eggs and juveniles/g root and final nematode population density. No signifycant correlations were found between nematological parameters or plant growth parameters and amendment doses.

Effect of Meloidogyne incognita Inoculum Density and Application Rate of Paecilomyces lilacinus Strain 251 on Biocontrol Efficacy and Colonization of Egg Masses Analyzed by Real-Time Quantitative PCR

The fungal biocontrol agent, Paecilomyces lilacinus strain 251 (PL251), was evaluated for its potential to control the root-knot nematode Meloidogyne incognita on tomato at varying application rates and inoculum densities. Conversely to previous studies, significant dose-response relationships could not be established. However, we demonstrated that a preplanting soil treatment with the lowest dose of commercially formulated PL251 (2 × 10(5) CFU/g soil) was already sufficient to reduce root galling by 45% and number of egg masses by 69% when averaged over inoculum densities of 100 to 1,600 eggs and infective juveniles per 100 cm(3) of soil. To determine the role of colonization of M. incognita egg masses by PL251 for biocontrol efficacy, a real-time quantitative polymerase chain reaction (PCR) assay with a detection limit of 10 CFU/egg mass was used. Real-time PCR revealed a significant relationship between egg mass colonization by PL251 and the dose of product applied to soil but no correlation was found between fungal density and biocontrol efficacy or nematode inoculum level. These results demonstrate that rhizosphere competence is not the key mode of action for PL251 in controlling M. incognita on tomato.

Evaluation of Efficacy of Paecilomyces Lilacinus as Biological Control Agent of Meloidogyne Incognita Attacking Tomato

Evaluation of Efficacy of Paecilomyces Lilacinus as Biological Control Agent of Meloidogyne Incognita Attacking Tomato The efficacy of Paecilomyces lilacinus strain UP1 as biological control agent of Meloidogyne incognita attacking tomato was evaluated under screenhouse condition pot experiments. P. lilacinus was formulated on rice substrate in powder form. Root weight, gall index rating, number of galls, egg masses and nematodes per one gram root sample were determined and per cent reduction in gall number was computed. Root weight and gall index ratings were significantly higher in untreated plants than those with P. lilacinus and with the commercial fungicide Nemacur. Number of galls, nematodes and egg masses per one gram root sample were significantly reduced by the application of P. lilacinus at all levels and this was comparable with Nemacur. However, egg mass count in plants treated with the lowest concentration of the biocontrol agent was not significantly different from the uninoculated control. Per cent reduction in gall number was the highest at treatment with 7.92 × 106 spores per ml of P. lilacinus.

A novel screening strategy to identify biocontrol fungi using protease production or chitinase activity against Meloidogyne root-knot nematodes

We isolated 137 fungal strains from females and eggs of Meloidogyne spp. collected from plant roots and infested soil in Jiangsu, China, and examined their in vitro protease production and chitinase activities. We then selected 20 strains, each with a protease production higher than 2 (protease production was measured as the ratio of diameters of the zone of clearing to that of the colony) and a chitinase activity higher than 0.2 U/min mL. For these strains, we examined their egg parasitic rates, mortality rates of stage 2 juvenile (J2), egg hatching rates and evaluated their biocontrol efficacies under greenhouse conditions. The biocontrol efficacies of these 20 potential biocontrol fungal strains ranged from 29 to 58%. The actual biocontrol efficacy against Meloidogyne root-knot was highly correlated with the in vitro protease production (r=0.82), chitinase activity (r=0.80), and mortality of J2 (r=0.76), but poorly correlated with the egg parasitic rate (r=0.51) and the egg hatch rate (r=0.52). Based on these results, we suggest that in vitro protease production or chitinase activities of the fungal strains could be an applicable indicator for assessing biocontrol efficacy against nematodes. This notion was also supported by our field experiments on tomatoes with Paecilomyces lilacinus strains XT18, XCS46 and Pochonia chlamydosporia strain XT124, which reached the biocontrol efficacies of 60.7, 51.5 and 48.1% in 2007; and 67.8, 57.3 and 53.2% in 2008, respectively.

Spore production in Paecilomyces lilacinus (Thom.) samson strains on agro-industrial residues

Paecilomyces lilacinus has potential for pests control. We aimed to analyze mycelial growth and spore production in P. lilacinus strains in several agro-industrial residues and commercial media. This study suggests alternative nutrient sources for fungi production and that the biotechnological potential of agro-industrial refuses could be employed in byproducts development.

Persistence of the nematophagous fungus Paecilomyces lilacinus strain 251 in soil under controlled conditions

The persistence of the nematophagous fungus Paecilomyces lilacinus Samson strain 251 (PL251) and the effect of application rate, substrate type, as well as the presence of the nematode host on its dynamics after application to the soil were investigated under controlled conditions. In all experiments, increase of P. lilacinus colony forming units after application was not found. In contrast, a gradual decline in fungal densities over time was observed. Application rate had no significant effect on the dynamics of the fungal population. Likewise, P. lilacinus density decline in soil was not significantly affected by the presence of the nematode host. Substrate type had a significant effect on P. lilacinus persistence in soil. The fungal agent persisted longer in silty loam and clay soil, with reduced persistence when sand was added to field soil. Conversely, when organic substrate was added to pure sand, persistence was significantly increased. Although persistence of fungal biocontrol agents in soil depends on various biotic and abiotic conditions, baseline data on persistence such as those reported in this study are helpful for biocontrol and environmental risk assessment and merit further study.

Biological control of Radopholus similis in banana by combined application of the mutualistic endophyte Fusarium oxysporum strain 162, the egg pathogen Paecilomyces lilacinus strain 251 and the antagonistic bacteria Bacillus firmus

The biological control efficacy of single or multiple applications of the mutualistic endophyte Fusarium oxysporum strain 162, the egg pathogen Paecilomyces lilacinus strain 251 and the antagonistic bacteria Bacillus firmus toward Radopholus similis was investigated in pot trials with banana under glasshouse conditions. R. similis was controlled substantially in single and combined applications of F. oxysporum with P. lilacinus or B. firmus. The combination of F. oxysporum and P. lilacinus caused a 68.5% reduction in nematode density whereas the individual applications reduced the density by 27.8% and 54.8% over the controls, respectively. Combined application of F. oxysporum and B. firmus was the most effective treatment in controlling R. similis on banana (86.2%), followed by B. firmus alone (63.7%). The compatibility of the biocontrol agents, as well the capacity of F. oxysporum to colonize banana roots in the absence or presence of P. lilacinus was also investigated. P. lilacinus did not adversely affect endophytic colonization by F. oxysporum. Biological control of R. similis in banana can therefore be enhanced via combined applications of antagonists with different modes of action that target different stages in the infection process.