Use Of Biocontrol Agents Research Articles

Failure of biological control of Frankliniella occidentalis on protected eggplants using Amblyseius swirskii in the Mediterranean region of Turkey

The western flower thrips, Frankliniella occidentalis (Pergande), is one of the most important insect pests in the Mediterranean region of Turkey. Thrips infestation is the main cause of vegetable crops losses in low polythene tunnels and plastic greenhouses. Chemical control has been the primary means to control F. Occidentalis in protected cultivation systems in Turkey. A search of alternatives to conventional insecticides for the control of F. Occidentalis has drawn increased interest in the use of biocontrol agents. This study evaluated the control efficiency of F. Occidentalis on eggplants through releases of the predatory mite Amblyseius swirskii (Athias-Henriot) at a rate of 50 adults per m2 in plastic greenhouses or low polythene tunnels. Samplings of F. Occidentalis from flowering to harvesting of the eggplants revealed that neither preventative nor curative releases of the predatory mite reduced the thrips population densities below a mean of 3 thrips per flower (i.e. Control threshold). We discuss various factors that may have affected the efficiency of the predatory mite on eggplants or the failure of the biological control.

Endophytic Microorganisms Isolated of Plants Grown in Colombia: A Short Review

Colombia is listed as the second largest country in plant diversity in the world, presenting more than 6000 species of endemic plants. The different genus and species of plants, as well as the various environments encountered in the country, are responsible for the countless amount of endophytic bacteria and fungi. So far, only a few endophytic microorganisms were isolated in Colombia, including the genera Pseudomonas, Burkholderia, Chromobacterium, Curtobacterium, Acremonium, Alternaria, Aspergillus and Fusarium, which have been isolated from rice, coffee, rose, grass and Espeletia plants. Fungi and bacteria isolated from these plants have great potential for use in biocontrol, bioremediation and in promoting plant growth. Colombia for its rich flora have become a promising country for finding new microorganisms associated with plants, especially those with potential for food industry, pharmaceuticals and agriculture.

Potential New Associations of North American Parasitoids With the Invasive Asian Longhorned Beetle (Coleoptera: Cerambycidae) for Biological Control.

The Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), is a polyphagous wood-boring insect native to Asia. Since it invaded North America in the 1990s, the beetle has been continuously targeted by quarantines and eradication programs in the United States and Canada. We examined the potential for development of new species-associations between A. glabripennis and hymenopteran parasitoids collected from cerambycids and other wood-boring insects infesting red maple (Acer rubrum L.) trees in the mid-Atlantic region of the United States. Results of our study showed that five groups of braconid parasitoids (Ontsira mellipes Ashmead, Rhoptrocentrus piceus Marsh, Spathius laflammei Provancher, Heterospilus spp., and Atanycolus spp.) successfully attacked early instars of A. glabripennis larvae infesting red maple logs and produced both male and female progenies. One species, O. mellipes, was continuously reared on A. glabripennis larvae inserted inside small red maple sticks for over 50 generations, and produced female-biased progeny (∼6:1 female to male ratio) at each generation. Continuous rearing of O. mellipes on A. glabripennis larvae did not significantly increase the parasitism and mean number of progeny produced per parasitized host. Together, these findings demonstrate that some North American parasitoids may be able to develop new associations with A. glabripennis and thus should be further studied under semifield or field conditions for possible use in biocontrol.

Temperature-specific competition in predatory mites: Implications for biological pest control in a changing climate

Climate change is affecting the future of sustainable agriculture, because increasing temperatures may interfere with the functioning of natural enemies that are used in biological pest control. In this work, we examined the role of abiotic conditions in shaping the structure of a simple agricultural community that is dominated by two species of predatory mites (i.e., Eusieus stipulatus and Eusieus scutalis) competing for resources. Population and community dynamics experiments were carried out at two abiotic conditions mimicking local climates in a Mediterranean region, to estimate the population carrying capacity (k) and interspecific competition (α) for each predatory mite species. Subsequently, we used this data to parameterize a competition model, thereby predicting species dominance at each abiotic condition. To test our model predictions, we sampled several orchards located in areas influenced by each of the local climates, to determine the abundance of each species of natural enemy. Results showed that the outcome of the competitive interactions between predatory mites was strongly affected by abiotic conditions, leading to temperature-dependent changes in the community structure. Furthermore, the pattern of species dominance found in the field agreed with the model predictions built upon our laboratory experiments. We therefore emphasize that, in a changing climate, if we are to guarantee the successful use of biocontrol agents, we need to account for the effect of temperature upon biotic interactions.

The Interaction between Endophytic Actinomycetes and Rhizobium in Leguminous Plants

Biological N2 fixation represents the major source of N input in many agricultural soils including those in arid regions where little artificial fertilizer is applied. The major N2-fixing systems in agriculture are the symbiotic systems, where bacteria such as rhizobia interact with legumes to fix atmospheric nitrogen which plays a significant role in improving the fertility and productivity of low-N soils. The symbiotic association of legume-rhizobium is initiated by the colonization of the rhizosphere by the rhizobia and subsequent attachment to the root hairs of the host plant. Furthermore, the host will produce flavonoids, such as luteolin in alfalfa and diazedin in soybean, which interact with nod protein in the rhizobia. Moreover, this process then elicits the expression of a cluster of nodulation genes such as nod, nol, and noe in the rhizobia. The interaction is potentially of great importance to the health and growth in nature of this nodulating legume.The interaction between endophytic Actinomycetes and rhizobia in leguminous plants is one way to improve the capability of leguminous plants to fix atmospheric nitrogen in plant roots and contribute to the plants nutrition. From other studies, we know that certain types of Actinomycetes, for example Streptomyces, interact with peas to form healthy roots as an effective site to form nodules and improve biological nitrogen fixation. Knowledge about this activity against fungal pathogens might lead to finding biocontrol agents for use in sustainable agricultural practices.Root-colonizing soil borne Actinomycetes might influence root nodulation in leguminous plants by increasing root nodulation frequency, possibly at the sites of infection by Rhizobium spp. Actinomycetes also colonize and sporulate within the surface cell layers of the nodules. This colonization leads to an increase in the average size of the nodules that form and improves the vigor of the bacteroids which generate the red color within the nodules by enhancing nodular assimilation of iron and possibly other soil nutrients. Keywords: symbiotic, biological, nitrogen, molecular interaction

Elevation of Defense Network in Chilli Against Colletotrichum capsici by Phyllospheric Trichoderma Strain

Biocontrol strategies have been mainly focused on proposing the use of biocontrol agents (BCAs) isolated from the rhizospheric region of the plant for protection against phytopathogens. The present study evaluates the effectiveness of phyllospheric Trichoderma isolates in elevating the defense responses in chilli against Colletotrichumcapsici infection and comparing its efficiency to the conventionally recommended rhizospheric Trichoderma strains. The elicitation of the defense network in the plants was analyzed using biochemical assays for important enzymes, that is, PAL, PO, PPO, TPC, SOD along with the total protein level in challenged plants over untreated and unchallenged control plants. The results recorded 2.1, 5.18, 3, 0.67, and 0.5-fold increases in TPC, PAL, PO, PPO, and total protein content in BHUF4 (phyllopsheric Trichoderma isolate)-treated plants when compared to control plants under C. capsici challenge. This was at par with the increment recorded in T16A (rhizospheric Trichoderma isolate)-treated chilli plants. The increment in growth parameters was also recorded after treatment with the isolated Trichoderma strains. Interestingly, the phyllospheric isolate (BHUF4) treatment recorded comparable growth promotion in chilli plants recording 36, 62, and 60 % increases in one of the major parameters of plant growth, that is, root length, no. of leaves, and dry weight, respectively. This study proposes the use of combined application of both rhizospheric as well as phyllospheric Trichoderma isolates for better and all around protection of plants against foliar as well as soil phytopathogens. This would be a novel approach in biological control strategy for better management of anthracnose disease of chilli.

Putative type 1 thymidylate synthase and dihydrofolate reductase as signature genes of a novel Bastille-like group of phages in the subfamily Spounavirinae.

BackgroundSpounavirinae viruses have received an increasing interest as tools for the control of harmful bacteria due to their relatively broad host range and strictly virulent phenotype.ResultsIn this study, we collected and analyzed the complete genome sequences of 61 published phages, either ICTV-classified or candidate members of the Spounavirinae subfamily of the Myoviridae. A set of comparative analyses identified a distinct, recently proposed Bastille-like phage group within the Spounavirinae. More importantly, type 1 thymidylate synthase (TS1) and dihydrofolate reductase (DHFR) genes were shown to be unique for the members of the proposed Bastille-like phage group, and are suitable as molecular markers. We also show that the members of this group encode beta-lactamase and/or sporulation-related SpoIIIE homologs, possibly questioning their suitability as biocontrol agents.ConclusionsWe confirm the creation of a new genus—the “Bastille-like group”—in Spounavirinae, and propose that the presence of TS1- and DHFR-encoding genes could serve as signatures for the new Bastille-like group. In addition, the presence of metallo-beta-lactamase and/or SpoIIIE homologs in all members of Bastille-like group phages makes questionable their suitability for use in biocontrol.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1757-0) contains supplementary material, which is available to authorized users.

Innovative strategies based on the use of bio-control agents to improve the safety, shelf-life and quality of minimally processed fruits and vegetables

The consumption of minimally processed fruits and vegetables has increased in recent years. Currently, the use chemical preservatives is unable to guarantee the safety of minimally processed fruits and vegetables. These conditions have stimulated research into alternative methods for increasing their safety and shelf-life. The use of protective cultures, particularly lactic acid bacteria, microorganisms from indigenous microflora and their antimicrobial products, has been proposed for minimally processed products. However, the application of bioprotective cultures has been limited at the industrial level. In this perspective, the aim of this review was to summarize the state-of-the-art application of biocontrol agents in minimally processed fruits and vegetables and their action mechanisms against spoilage and/or pathogenic microorganisms.

Effect of photoperiod on slow and fast developing individuals in aphidophagous ladybirds, Menochilus sexmaculatus and Propylea dissecta (Coleoptera: Coccinellidae).

The effects of environmental parameters on insect development have been studied extensively. But the reasons for 2 differential developmental rates within same cohort under varying environmental factors have not been explored. For the purpose, in this study the existence and stability of slow and fast development under 5 photoperiods (i.e., 8L: 16D, 10L : 14D, 12L : 12D, 14L : 10D and 16L : 8D; light and dark hours per day) and its effect on body mass and reproductive attributes in 2 aphidophagous ladybirds, Menochilus sexmaculatus (Fabricius) and Propylea dissecta (Mulsant) was examined on Aphis craccivora Koch at 27 ± 1 °C temperature. A clear bimodal (2 peaks, where the first peak represented the fast developing and the 2nd peak slow developing individuals) pattern of distribution at each photoperiod was found. The proportion of slow and fast developing individuals in a cohort differed with photoperiods. The slow developing individuals were more in numbers at 8L : 16D, in equal numbers at 14L : 10D and in less numbers at 16L: 8D, indicating that the variation in emergence was owing to exogenous cues influenced differential rates of mortality. Slow developing individuals had female biased sex ratio, higher longevity and lower body mass than fast developing individuals. Fast developing females laid higher numbers of eggs with higher egg viability than slow developing females. Study of such variations in development at different photoperiods is helpful to understand its role in the development of insects particularly ladybirds and permits the selection of fast developing bioagents for their use in biocontrol of pest species.

Identification and pathogenicity of bacteria in the Mediterranean corn borerSesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae)

Sesamia nonagrioides (Lep.: Noctuidae) is one of the most serious pests of corn in Turkey and other Mediterranean countries. Although various cultural, chemical, and biological methods are used to control this pest, its damage still continues in all Mediterranean countries. In this study, to find an effective bacterium that can be used as a biocontrol agent against S. nonagrioides, we isolated 15 bacteria from S. nonagrioides larvae and evaluated the larvicidal potency of all isolates on the pest. According to their morphological, physiological, biochemical, and molecular properties, the isolates were identified as Achromobacter insolitus (Sn1), Morganella morganii (Sn2), Klebsiella pneumoniae (Sn3), Citrobacter freundii (Sn4), Arthrobacter protophormiae (Sn5), Chryseobacterium indologenes (Sn6), Bacillus thuringiensis (Sn7), Bacillus safensis (Sn8), Bacillus thuringiensis (Sn9), Bacillus thuringiensis (Sn10), Klebsiella pneumoniae (Sn11), Staphylococcus sciuri (Sn12), Enterobacter kobei (Sn13), Serratia marcescens (Sn14), and Microbacterium arborescens (Sn15). The results of the larvicidal activities of these isolates indicated that the mortality value obtained from all treatments varied from 25% to 93%, reaching 93% with B. thuringiensis (Sn10) for the third-instar larvae within 10 days of the application of 1.89 × 109 cfu/mL bacterial concentration at 25 °C in laboratory conditions. However, the dose-response experiments showed that increasing the concentration of bacteria gradually increased larval mortality, which reached 100% with a 2-fold concentration of Sn10. The findings of this study indicate that this isolate appears to be a promising biocontrol agent for use against S. nonagrioides.

Role of antagonistic microorganisms and organic amendment in stimulating the defense system of okra against root rotting fungi

Without application of chemical pesticides control of soilborne diseases is a great challenge. Stimulation of natural plant's defense is considered as one of the most promising alternative strategy for crop protection. Organic amendment of soil besides direct suppressing the pathogen, has been reported to have an influence on phytochemicals in plants. In the present study, Pseudomonas aeruginosa, a plant growth promoting rhizobacterium and Paecilomyces lilacinus, an egg parasite of root knot and cysts nematodes were examined individually and in combination in soil amended with cotton cake for suppressing the root rotting fungi and stimulating the synthesis of polyphenols and improving the antioxidant status in okra. Application of P. aeruginosa and P. lilacinus in soil amended with cotton cake significantly (P < 0.05) suppressed Macrophomina phaseolina, Fusarium oxysporum, and Fusarium solani with complete reduction of Rhizoctonia solani. Combine use of biocontrol agents in cotton cake amended soil showed maximum positive impact on plant growth, polyphenol concentration and antioxidant activity in okra.

The arbuscular mycorrhiza fungusRhizophagus irregularisMUCL 41833 decreases disease severity of Black Sigatoka on banana c.v. Grande naine, underin vitroculture conditions

Introduction. Mycosphaerella fijiensis, the fungal pathogen causing Black Sigatoka disease, attacks almost all cultivars of bananas and plantains. Currently, the repeated application of fungicides is the most widespread control measure, while the use of bio-control agents remains almost ignored. Here we investigated, under in vitro culture conditions, whether an arbuscular mycorrhizal fungus (AMF – Rhizophagus irregularis MUCL 41833) could reduce the severity of disease caused by M. fijiensis MUCL 47740 on banana. Materials and methods. Prior to their transfer to autotrophic in vitro culture systems and subsequent inoculation by the pathogen, the banana plantlets cultivar Grande Naine (AAA genome Cavendish group) were grown in the extra-radical mycelium network of the AMF, arising from Medicago truncatula plantlets, for fungal root colonization. Results and discussion. At the time of infection with M. fijiensis, the AMF colonization of the banana plantlets was 12%, 56% and 10% for hyphae, arbuscules and spores/vesicles, respectively, and the number of spores produced in the medium was above 200. At day 21 and day 35 following infection by the pathogen, the number of extra-radical spores as well as the abundance of arbuscules in roots, were significantly higher than in the non-infected plantlets. Conversely, the severity index measured in the mycorrhizal plantlets decreased by more than 80% and 60%, respectively, 21 and 35 days after infection by the pathogen. Similarly, the area under disease progress curve, estimated at day 35, was reduced by 59% in the mycorrhizal banana plantlets as compared to the control plantlets. Whatever the treatment (mycorrhizal or non mycorrhizal plantlets in presence/absence of M. fijiensis), no significant differences were observed in plantlet dry weight, pseudostem height and diameter, and leaf area at both observation times. Conclusions. These results emphasize the complex multitrophic interactions between above and below-ground microorganisms mediated via the plant. They further suggest that AMF may decrease, at least at the early stage of infection, M. fijiensis symptoms possibly via the induction of a systemic resistance pathway. The important decrease in symptoms observed in the mycorrhizal banana plantlets suggest that these microorganisms may represent a potentially attractive option to consider in the context of an integrated control of this important disease.

Biological Management of Damping-Off, Buckeye Rot and Fusarial Wilt of Tomato (cv. Solan Lalima) under Mid-Hill Conditions of Himachal Pradesh

Disease management is often complicated by the presence of multiple types of pathogens; in an organic system, it is appropriate to develop disease control strategies. The available literature so far reflects that the management of important disease of tomato is through the integrated approaches and very few organic approaches have been tried with various degree of success. Boiopriming of seeds with biocontrol agents (Trichoderma viridae, Trichoderma harzianum and Pseudomonas fluorescens) in combination with different biofertilizers (Azotobacter, Azospirillum and PSB) and organic manures (FYM and vermi-compost) were tested against disease incidence and health management of tomato seedling under nursery as well as field conditions. The studies were conducted during two successive years (2012-2013) at farmer’s field with the objective to combat with the increasing disease incidence of three major disease damping-off, fusarium wilt and buckeye rot from nursery stage to the final harvesting. The study focused on the use of biocontrol agents as the suitable alternative to chemical pesticides with sustainable disease management without pesticide residues in foodstuff. The bio priming of seeds with fungal antagonist Trichoderma viridae and harzianum and bacterial antagonist Pseudomonas fluorescens significantly improved the germination behavior of tomato seeds as compared to untreated control. Highest mean germination (93.1%) and seedling vigour (953.33) was recorded in Treatment 3 (FYM @ 200 q/ ha + Azospirillum + PSB + Trichoderma herzianum (4 kg/ha each) and lowest in control (60.3%) and (304.83), thus indicating a significant per cent increase in seedling emergence (54.4%) and seedling vigour (95.23%). A considerable reduction in disease incidence (pre and post) of damping off was observed in treatment T? and T? (VC @ 50 q/ha + Azospirillum + PSB + Trichoderma herzianum @ (4 kg/ha) with 45.6% and 35.4% respectively). Treatment T? proved highest in terms of yield (665 Kg/Ha), Hence these diseases can be managed by successful application of Biocontrol agents.

Evaluation of Some Bacillus spp. Strains for the Biocontrol of Fusarium graminearum and F. culmorum in Wheat

Fusarium graminearum Schwabe - teleomorph Gibberella zeae (Schwein.) Petch. and F. culmorum (W.C.Smith) Sacc. are the most important head-blighting pathogens of wheat in many regions of the world, including Romania. The strategies developed for the control of Fusarium spp. infections on cereals include agrotechnical practices, resistant cultivars, and fungicides use. However, the toxicity of fungicides and the low efficacy of such products to control members of the Fusarium head blight (FHB) Complex led to the development of additional strategy that can be used as part of an integrated management of FHB (directed against fungal growth and/or mycotoxins biosynthesis and accumulation). The use of biocontrol agents is an important strategy for integrated management of fungal diseases in many economically important plat species. It was shown that Bacillus spp strains could suppress various soil borne diseases, their efficacy being associated with their antagonistic properties and competitiveness in the rhizosphere (including through sporulation). The aim of this study was the “in vitro” evaluation of biocontrol capacity of different Bacillus spp. strains isolated from soil and compost against strains of Fusarium graminearum and F. culmorum. The ability of four strains of bacilli (B1, B3, B5 and BIR) to inhibit fungal growth was established. For their identification BIOLOG system was used, coupled with molecular techniques (ARDRA). It was proved that the strains of interest belong to Bacillus amyloliquefaciens (BIR and B3) and Bacillus spp. (B1 and B5). The Bacillus amyloliquefaciens strains, BIR and B3, were also evaluated in pot experiments, in climatic chamber conditions, for their ability to stimulate wheat seeds germination and/or plantlet growth and reduce Fusarium infections in first stages of wheat vegetation. After 21 days of incubation significant differences were registered between variants infected with Fusarium and supplemented with Bacillus and control variants, not only in germination rate but also in wheat plantlets development. Further differences were observed in the number of Fusarium CFU/g of soil from the soils treated with bacteria in contrast with control variants.

Remarkable diversity of Salmonella bacteriophages in swine and poultry.

The diversity of 55 Salmonella-specific bacteriophages isolated from 191 fecal samples of poultry and swine from farms located in diverse geographic areas of Spain was determined using lysis profiling, DNA restriction and random amplification of polymorphic DNA (RAPD-PCR). Among them, lysis profiling and RAPD-PCR exhibited 100% typeability and DNA restriction 96%, with discriminatory power of 0.978 (± 0.016), 0.938 (± 0.028) and 0.982 (± 0.013), respectively. The highest concordance (0.974) was that between RAPD-PCR and lysis profiling. None of the bacteriophages isolated from poultry and swine shared any DNA restriction or RAPD-PCR patterns and only two lysis profiles were common to bacteriophages isolated from poultry and swine. The major part of the lysis and RAPD-PCR profiles from the bacteriophages isolated from poultry included only one or two bacteriophages, while those obtained from swine contained more than two bacteriophages. Overall, our results provide evidence of the remarkable diversity exhibited by bacteriophages of Salmonella in farm animals. Moreover, they also show that RAPD-PCR may also be suitable for the pre-screening of the diversity of Salmonella bacteriophages for further use in biocontrol and therapeutic strategies.

Evaluation of the biocontrol potential of Streptomyces goshikiensis YCXU against Fusarium oxysporum f. sp. niveum

A rhizobacterium with broad spectrum antifungal activity was isolated from the rhizosphere of a healthy cucumber plant in a Fusarium wilt diseased field. Phylogenetic tree analysis based on similarity percentage showed that the bacterium was 99% affiliated with the species Streptomyces goshikiensis. The strain, coded as S. goshikiensis YCXU, inhibited in vitro a broad range of phytopathogenic fungi, so it was selected for more detailed characterization. The strain could utilize different carbon sources and exhibited catalase, β-1,3-glucanase, chitinase and urease enzyme activities. The strain showed maximum growth at the pH of 7, temperature of 28°C and NaCl concentration of 1%. The stain was able to produce antifungal diffusible and volatile organic compounds that significantly inhibited the growth of pathogenic fungi. In the greenhouse experiments, watermelon plants fresh and dry weights were significantly increased, and the incidence of Fusarium wilt was decreased by 67% when the strain enriched by a bioorganic fertilizer was applied to both nursery soil and pot soil (NS). The treatment NS also showed 88.9% less pathogen population in soil as compared to control. The use of biocontrol agents decreased the stress indicator enzymes and malondialdehyde content by 55–70% and 62%, respectively as compared to control. The denaturing gradient gel electrophoresis (DGGE) analysis showed significant variations in the fungal and bacterial community structures of all treatments resulted from UPGMA cluster analysis. This study showed that S. goshikiensis YCXU could be a potential biocontrol agent for controlling watermelon Fusarium wilt disease.

Bahasa Indonesia

One of the factors affected production of tomato is the incidence of bacterial wilt disease caused by Ralstonia solanacearum . An alternative control to manage the disease which is environmentally friendly is the use of biocontrol agents. Application of endophytic bacteria ( Staphylococcus epidermidis BC4) and plant growth promoting rhizobacteria ( Pseudomonas fluorescens RH4003 and Bacillus subtilis AB89) as biocontrol of tomato bacterial wilt was expected to be an alternative method. The objective of this study is to evaluate the interaction among endophytic bacteria and PGPR to suppress the development of bacterial wilt disease ( R. solanacearum ) and promoting the growth of tomato. Bacterial treatment which caused the highest suppression on disease incidence was single application of P. fluorescens RH4003. Disease index caused by S. epidermidis BC4 and P. fluorescens RH4003 applied individually was up to 41.18 dan 45.88%, respectively. Interaction between the endophytic bacteria and both of the PGPRs were antagonistic.

Identification and characterization of the endophytic bacterium Bacillus atrophaeus XW2, antagonistic towards Colletotrichum gloeosporioides

Bacillus atrophaeus XW2 was isolated from healthy poplar leaves and exhibited a strong inhibitory effect against Colletotrichum gloeosporioides, a predominant fungus causing poplar anthracnose. The culture filtrate and bacterial lysate of XW2 were antagonistic against hyphal growth and spore germination. The average diameter of the inhibition zones of hyphal growth were 22.3 mm for the culture filtrate and 12.1 mm for the bacterial lysate. The average inhibition rates of spore germination after 24 h were 94.6 % for the culture filtrate and 88.8 % for the bacterial lysate. In the presence of both culture extracts, hyphae developed vacuoles and swelling, and abnormalities were observed in 100 % of germinated spores. Lipopeptides isolated from culture filtrate and bacterial lysate had high antifungal activities against C. gloeosporioides. The average diameter of the inhibition zones were 23.2 mm for culture filtrate and 11.8 mm for bacterial lysate. Crude proteins isolated from culture filtrate and bacterial lysate also showed good inhibition qualities. The average diameters for the zones of inhibition were 22.3 mm for culture filtrate and 13.4 mm for bacterial lysate. Volatiles produced by XW2 inhibited hyphal growth of C. gloeosporioides by 60.2 % and were antagonistic against the germination of C. gloeosporioides spores after 3 days. Greenhouse studies revealed that XW2 had a 49.1 % efficacy in controlling poplar anthracnose 12 days after exposure to the pathogen. We consider that Bacillus atrophaeus XW2 is a promising natural biocontrol agent for use against C. gloeosporioides.

Phylogeography of the ladybird Iberorhyzobius rondensis, a potential biological control agent of the invasive alien pine bast scale Matsucoccus feytaudi

Understanding the genetic structure of natural enemies is an important step to develop efficient biocontrol programs. The ladybird Iberorhyzobius rondensis Eizaguirre (Coleoptera: Coccinellidae) from the Iberian Peninsula, is a specialized predator and potential biological control of Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae), an invasive alien species in Southeastern France and Italy. M. feytaudi is specialized on Pinus pinaster Aiton. The beetle is also restricted to this habitat. Genetic structure of I. rondensis populations was analysed with the barcode region (COI). It revealed two main refugia areas for the beetle in Iberian Peninsula. Comparative phylogeography of the three trophic levels, plant-herbivore-predator, is discussed. Similar population structure was found for the prey and to some extent for the pine. Indications are given on where to collect the beetles for their use in biocontrol of M. feytaudi, in order to obtain the highest genetic diversity and match with the origin of the invasive prey.

Efeitos de isolados do fungo Isaria (Persoon) sobre o cupim subterrâneo Coptotermes gestroi (Wasmann) (Isoptera: Rhinotermitidae)

Coptotermes gestroi (Wasmann) é considerada uma das espécies mais destrutivas de cupins subterrâneos, por causar danos a edificações, à arborização urbana e a culturas. Uma alternativa para o controle desse inseto pode ser o uso de agentes biocontroladores, como os fungos entomopatogênicos. Isaria (Persoon) tem sido indicado no controle de térmitas subterrâneos, inclusive do gênero Coptotermes. Dessa forma, o presente trabalho teve como objetivo selecionar isolados de Isaria patogênicos ao cupim C. gestroi. Os insetos pulverizados com suspensões fúngicas de I. farinosa, I. fumosorosea e I. javanica foram avaliados diariamente para a determinação da mortalidade. Todos os isolados foram patogênicos, ocasionando mortalidade acima de 70%, e virulentos, apresentando uma sobrevivência média de 2,0 a 3,9 dias. Contudo, os isolados ESALQ-1205 de I. farinosa, ESALQ-1296 de I. fumosorosea e os isolados URM-4995 e URM-4993 de I. javanica mostraram-se mais virulentos. A CL50estimada para os isolados ESALQ-1205 de I. farinosa, URM-4995 de I. javanica e ESALQ-1296 de I. fumosorosea resultou em valores de 3,7 x 105, 1,4 x 106e 2,7 x 106conídios mL-1, respectivamente. Tais resultados confirmam a eficiência dos isolados testados sobre os operários de C. gestroi. No entanto, novos estudos são necessários para verificar a melhor forma de utilização, bem como a sua efetividade em campo.