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SELECTION OF Beauveria bassiana AND Metarhizium anisopliae ISOLATES FOR THE CONTROL OF Blissus antillus (Hemiptera: Lygaeidae)

SELECTION OF Beauveria bassiana AND Metarhizium anisopliae ISOLATES FOR THE CONTROL OF Blissus antillus (Hemiptera: Lygaeidae)

Chinch bugs of the genus Blissus (Hemiptera: Lygaeidae) are serious pests of maize, wheat, sorghum and various grasses in the USA (Spike et al., 1994). In Brazil, a chinch bug recently identified as Blissus antillus (Leonard), causes serious damage to pastures planted with Brachiaria arrecta (T. Dur and Schinz) (tanner grass) and tangola grass (hybrid of B. arrecta and Brachiaria angola), in the states of Minas Gerais, Mato Grosso do Sul and Rio de Janeiro (Valério et al., 2000). To date, the only control method available for these insects is the ap- plication of insecticides. However, the use of insecticides
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Advances and Perspectives of the Use of the Entomopathogenic Fungi Beauveria bassiana and Metarhizium anisopliae for the Control of Arthropod Pests in Poultry Production

Advances and Perspectives of the Use of the Entomopathogenic Fungi Beauveria bassiana and Metarhizium anisopliae for the Control of Arthropod Pests in Poultry Production

The lesser mealworm A. diaperinus rapidly adapts to poultry house environmental conditions, and colonize the litter (Axtell & Arends, 1990). It was probably first introduced in poultry farms by contaminated feed, as it is a secondary pest of meals, feeds, and by-products of stored grains (Pacheco & Paula, 1995). In cold regions, where the use of thermal insulation is required in poultry houses, that insect makes perforations, causing structural damage in up to 30% of the insulating material (Steelman 1996). Lesser mealworms may also be vectors of viruses, bacteria, fungi, protozoa, and helminths that cause diseases in poultry, as shown by several studies (Chernaki-Leffer et al., 2002; Bates et al., 2004; Segabinazi et al., 2005; Hazeleger et al., 2008; Agabou & Alloui, 2010; Chernaki-Leffer et al., 2010; Alborzi & Rahbar, 2012). Crippen et al. (2012), in particular, demonstrated that they are vectors of Salmonella, one of the main pathogens found in poultry houses.
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Effects of Beauveria bassiana (Bals) Vuill and Metarhizium anisopliae (Metsc) Sorok on engorged females of Amblyomma cajennense (Fabricius, 1787) in laboratory conditions.

Effects of Beauveria bassiana (Bals) Vuill and Metarhizium anisopliae (Metsc) Sorok on engorged females of Amblyomma cajennense (Fabricius, 1787) in laboratory conditions.

treatments in concentrations of 10 5 ,10 6 ,10 7 e10 8 conidia/ml. A control group was also used. The following characteristics were evaluated: weight and period of oviposition, indexes of reproductive and nutritional efficiency and percentage of microbiological control. A dose dependent negative effect was observed in ticks treated with the suspension. All isolates tested cause a negative effect on in vitro tests of engorged females of A. cajennense, suggesting its potential for microbiological control of tick’s species.
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Patogenicidade de fungos hifomicetos aos pulgões Aphis gossypii Glover e Myzus persicae (Sulzer) (Hemiptera: Aphididae).

Patogenicidade de fungos hifomicetos aos pulgões Aphis gossypii Glover e Myzus persicae (Sulzer) (Hemiptera: Aphididae).

ABSTRACT - The aphids Aphis gossypii and Myzus persicae are cosmopolitan, poliphagous and damage cultivated plants. The effects of the entomopathogenic fungi Beauveria bassiana (isolate IBCB 66), Metarhizium anisopliae (isolate IBCB 121), Paecilomyces fumosoroseus (isolate IBCB 141) and Lecanicillium (= Verticillium) lecanii (isolate JAB 02) on third instar nymphs of A. gossypii and M. persicae were evaluated in the laboratory at 25°C, 70 ± 10% RH and 12h photophase. The aphids were transferred to petri dishes with a foliar disk (cotton or pepper) with a layer of 1 cm tick of agar-water. The fungi were applied in a suspension containing 1.0 x 106 to 1.0 x 108 conidia/ml. In the control treatment 1 ml of sterilized water was added to the foliar disks. The mortality of aphids was evaluated daily. B. bassiana and M. anisopliae caused 100% mortality at the seventh day after inoculation, for both species. L. lecanii was the fungus that provided mortality later in the aphids and M. persicae was more susceptible to both fungi than A. gossypii.
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Compatibilidade de polímeros aos fungos Beauveria bassiana e Metarhizium anisopliae e a estabilidade dos seus produtos formulados

Compatibilidade de polímeros aos fungos Beauveria bassiana e Metarhizium anisopliae e a estabilidade dos seus produtos formulados

To evaluate compatibility, the fungi B. bassiana and M. anisopliae were cultured in PDA culture media containing 0.1, 0.5, 1.0, and 2.0% (m/v) hemicellulose. The culture media was previously autoclaved at 1.0 atm and 121ºC for 20 minutes, with the biopolymer incorporated into the culture media before solidification, at a temperature of approximately 45°C. Then, the mixture was poured into Petri dishes of 9.0 cm diameter, and the control only contained PDA culture media. After the solidification of the media, the fungi were inoculated at three specific points of the culture media with the aid of a platinum loop. The cultured dishes were incubated in a germination chamber for 7 days at a temperature of 25.5 ± 0.5°C and a photoperiod of 12 hours. Evaluations of the vegetative growth were performed by the direct measurement of the microbial growth halo in two perpendicular directions. Then, these colonies were cut out using a flame-sterilized scalpel and placed in test tubes with a 10 mL autoclaved suspension of distilled water and spreader-sticker (Tween  80) at 0.1% (m/v). This suspension was homogenized in a tube stirrer for extraction and subsequent determination of the number of conidia in a Neubauer chamber.
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Efeito de isolados de Metarhizium anisopliae (Metsch.) Sorok. e Beauveria bassiana (Bals.) Vuill. sobre o percevejo-do-colmo do arroz, Tibraca limbativentris Stal.

Efeito de isolados de Metarhizium anisopliae (Metsch.) Sorok. e Beauveria bassiana (Bals.) Vuill. sobre o percevejo-do-colmo do arroz, Tibraca limbativentris Stal.

Effect of Metarhizium anisopliae (Metsch.) Sorok. and Beauveria bassiana (Bals.) Vuill. Isolates on Rice Stem Bug, Tibraca limbativentris Stal ABSTRACT - The rice stem bug, Tibraca limbativentris Stal (Heteroptera: Pentatomidae), is an important pest of irrigated rice (Oryza sativa) crop in Brazil. The effect of isolates (CP) of the entomopathogenic fungi, Beauveria bassiana (Bals.) Vuill. (Bb) and Metarhizium anisopliae (Metsch.) Sorok. (Ma) was evaluated in the field using cages. In the 1st and 2nd experiments, conidial suspensions at dosages equivalents to 10 13 conidia/ha, were sprayed on the soil
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UNIVERSIDADE FEDERAL DE UBERLÂNDIA INSTITUTO DE CIÊNCIAS AGRÁRIAS – ICIAG PROGRAMA DE PÓS-GRADUAÇÃO EM QUALIDADE AMBIENTAL

UNIVERSIDADE FEDERAL DE UBERLÂNDIA INSTITUTO DE CIÊNCIAS AGRÁRIAS – ICIAG PROGRAMA DE PÓS-GRADUAÇÃO EM QUALIDADE AMBIENTAL

The objective of this work was to evaluate the ability of seedlings of Jacaranda mimosifolia D. Don to extract heavy metals (Cu, Zn and Mn) in soil under application of a consortium with five fungi plant growth promoters (FCPV) and of biochar. On the shoot and on the soil, were sprayed a solution containing the five fungal isolates: Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum and Trichoderma asperella. The treatments with biochar originated from the pyrolysis of sawdust received 1% (m/v) on the surface of the column. Applied treatments with contamination of Cu, Mn and Zn and with uncontaminated soil. After 45 days of growth, were evaluated mass of shoot and roots; concentration of Cu, Mn and Zn in aerial, roots in the soil and leachate; soil fertility; and photosynthetic parameters. The averages were subjected to analysis of variance and Scott-Knott test (p < 0.05). The experimental design used was the randomized block, with six repetitions. The FCPV have conditioned the growth of roots and the development of the shoot of seedlings on contaminated soil, statistically resembling the seedlings grown in soil without contamination. Fungi and biochar increased the potential of phytoremediation, primarily Mn and Zn. In addition, the combination of FPCV and biochar decreases leaching of Cu, Mn and Zn. The plant used has proved to be a potential tool for removal of heavy metals in the soil, especially for not presenting negative reflexes in your photosynthetic activity and consequently not influencing in your growth. In addition, the application of the FPCV and biochar improves the effectiveness of phytoremediation, concentrating the metals in plant tissues and reducing the risk of leaching.
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MATERIALS AND METHODS Fungal material

MATERIALS AND METHODS Fungal material

In Brazilian soybean fields, the entomopathogenic fungus Beauveria bassiana acts as a natural control agent for Aracanthus mourei (Col.: Curculionidae), Cerotoma sp., Diabrotica speciosa, and Colaspis sp. (Col.: Chrysomelidae), and interestingly, as an endophyte, this species also provides a protective effect against plant pathogens (Ownley et al., 2008). In addition, Metarhizium anisopliae plays an important role in controlling soil-inhabiting insects such as Scarabaeidae (Sosa-Gómez & Moscardi, 1994). The potential of entomopathogens as microbial control agents has been studied (Johnson & Goettel, 1993), but their dispersion patterns in crops following artificial application has received little attention. More emphasis has been placed on the dissemination of entomopathogens
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Seletividade de Beauveria bassiana e Metarhizium anisopliae a Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae).

Seletividade de Beauveria bassiana e Metarhizium anisopliae a Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae).

(30 cards/fungus = 30 replicates). Afterwards, females were isolated in glass tubes. The control group was sprayed with sterile distillated water + Tween 80 (0.01%). In addition, 60 cards with sterilized eggs of A. kuehniella were submitted to parasitism by females of T. pretiosum for 24h. Of these cards, 30 were sprayed with B. bassiana or M. anisopliae and 30 with distillated water + Tween 80 (0.01%), and observed daily until parasitoid emergence. Metarhizium anisopliae decreased parasitoid emergence and caused confi rmed mortality. Therefore, fi eld and semi-fi eld experiments should be conducted for a fi nal assessment of the side-effects of these entomopathogens on Trichogramma as a ways to develop a control strategy in which both can be used.
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EXTERNAL DEVELOPMENT OF THE ENTOMOPATHOGENIC FUNGI Beauveria bassiana AND Metarhizium anisopliae IN THE SUBTERRANEAN TERMITE Heterotermes tenuis

EXTERNAL DEVELOPMENT OF THE ENTOMOPATHOGENIC FUNGI Beauveria bassiana AND Metarhizium anisopliae IN THE SUBTERRANEAN TERMITE Heterotermes tenuis

ABSTRACT: The subterranean termite Heterotermes tenuis is one of the main pests of sugarcane and eucalyptus in Brazil, and the use of entomopathogenic fungi, alone or associated to chemicals, is an efficient and environmentally favorable method for its control. Studies related to the fungal development on these insects are important due to the effect of insect behavior on entomopathogens. The objective of this work was to describe the external development of Beauveria bassiana and Metarhizium anisopliae on H. tenuis using Scanning Electron Microscopy (SEM), determining the duration of the different phases of fungal infection. Two fixation techniques for preparing SEM samples were also evaluated. Worker specimens of H. tenuis were inoculated with a 1 x 10 9
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Potencial de isolados de Metarhizium anisopliae e Beauveria bassiana e do óleo de Nim no controle do pulgão Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae).

Potencial de isolados de Metarhizium anisopliae e Beauveria bassiana e do óleo de Nim no controle do pulgão Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae).

ABSTRACT - This work aimed to determine the eficiency of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae) in kale Brassica oleracea var acephala D.C., as well as their compatibility with a neem oil formulation (Neemseto®). Ten isolates of both fungi were tested and the most pathogenic ones were B. bassiana CG001 and M. anisopliae CG30 with 90% and 4.4 days, and 64% and 3.8 days of mortality and median lethal time, respectively. Bioassays with neem at concentrations of 0.5, 1.0 and 2.0% were done either by leaf discs dipping or spraying the aphids on the leaf discs. The neem spraying treatment at 2.0% provided 90% mortality. The use of B. bassiana isolate CG001 or M. anisopliae isolate CG30 with neem at 0.125, 0.25, and 0.5%, demonstrated that these isolates could have their spore viability or colony growth affected when exposed to neem concentrations higher than 0.25%. In absolute values, the isolates B. bassiana CG001 and M. anisopliae CG30 are the most virulent to L. erysimi, and could be utilized in the management of this pest.
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Resposta imune celular de Polybia platycephala (Hymenoptera: Vespidae) desafiado por Beauveria bassiana e Metarhizium anisopliae

Resposta imune celular de Polybia platycephala (Hymenoptera: Vespidae) desafiado por Beauveria bassiana e Metarhizium anisopliae

Monoculture reduces the environmental equilibrium, which favors the emergence of pests. The use of biopesticides in biological control is an effective alternative, but can affect natural enemies, which has motivated the search for selective methods to target organisms. Insects have immune system to defend against entomopathogen, but tolerance and the dynamics of the immune system in social wasps are still little known. Social wasps are important predators in biological control and are in constant contact with entomopathogenic organisms. The aim of the study was to identify and characterize the hemolymph cells of adult female Polybia platycephala Richards (Hymenoptera: Vespidae) and evaluate the impact of fungi Beauveria bassiana (isolated ESALQ PL 63) and Metarhizium anisopliae (isolated ESALQ E9) on survival and response hemocyte this social wasp. The morphological description of the hemocytes was performed by light microscopy. The dynamic changes in survival of P. platycephala hemocyte were studied in two categories: 1) different concentrations of fungal solution and 2) different time intervals. Four types of hemocytes were identified during the description of the morphology of these cells: prohemocytes, plasmatocytes, granulocytes and oenocytoids cells. The hemocytes of P. platycephala showed the same morphological pattern of other species of Hymenoptera. M. anisopliae high concentrations in the topical treatment (1 x 10 8 and 1 x 10 9 spores/ml) decreased survival and the number of granulocytes and prohemocytes P. platycephala. B. bassiana is pathogenic at all concentrations by contact, reducing the survival and the granulocyte number of P. platycephala. In the treatments if swallowed, B. bassiana was shown to be pathogenic to 1 x 10 9 spores/mL. Metarhizium anisopliae (isolated ESALQ E9) did not
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BIOLOGICAL CONTROL External Events Related to the Infection Process of Cornitermes cumulans (Kollar) (Isoptera: Termitidae) by the Entomopathogenic Fungi Beauveria bassiana and Metarhizium anisopliae

BIOLOGICAL CONTROL External Events Related to the Infection Process of Cornitermes cumulans (Kollar) (Isoptera: Termitidae) by the Entomopathogenic Fungi Beauveria bassiana and Metarhizium anisopliae

For studies of the cycle of entomopathogenic fungi on insects using scanning electron microscope (SEM), the technique of choice has included glutaraldehyde fixation followed by dehydration in ethanol series, and critical-point drying (Champlin et al. 1981, Lecuona et al. 1991). Fixation using OsO 4 vapor has also been used (Boucias & Pendland 1982, Gunnarsson 1988). Bidochka & Khachatourians (1992) air-dried specimens for 24h after the fixation and dehydration, in order to study the growth of Beauveria bassiana (Balsamo) Vuill. on the cuticle of the acridid Melanoplus sanguinipes (Fabricius). Fixation of the specimen by immersion can modify the structures of the pathogen. To avoid these problems with insects treated with Beauveria sp., Quattlebaum & Carner (1980) used fixation with OsO 4 for 96h, followed by air-drying for three to four days. Using this technique, the authors obtained minimal distortion of fungal structures. For quantitative studies in which the numbers of fungal structures in different regions of the insect body are important, fixation with OsO 4 vapor for 48h to 96h is recommended to prevent a possible loss of structures. However, when the objective is simply to detect structures with a few or no deformations, other techniques may be used. For insects with thin cuticle such as the mount termite Cornitermes cumulans (Kolar), fixation and critical point drying preserve both fungal and insect structures, making detailed observations possible.
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Suscetibilidade de Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) a entomopatógenos

Suscetibilidade de Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) a entomopatógenos

ABSTRACT: The research aimed to assess the suscetibility of two distinct Brazilian populations of Helicoverpa armigera to commercial Bacillus thuringiensis insecticides and isolates of Beauveria bassiana, Metarhizium anisopliae and Metarhizium rileyi.The pest populations were collected in soybean fields located in Rio Verde (GO) and Luís Eduardo Magalhães (BA), taken to laboratory and reared until the tenth generation on artificial diet, to be used in the experiment.The bioassays were performed using spherical plastic receptacles (2-cm diameter x 3- cm height) containing artificial diet until complete the half volume. The formulated products used were Dipel ® WP (B. thuringiensis var kurstaki), Xentari ® WG (B. thuringiensis var. aizawai) and Agree ® WG (B. thuringiensis var. aizawai GC91 with B. thuringiensis var. kurstaki), spraying 50 µL of biological product solution at 10 7 viable spores/mL, on the surface of the diet. One caterpillar was inserted in each receptacle, related with larval instar, totaling 100 caterpillars per treatment and each group containing 10 caterpillars were considered a replication. Mortality were assessed each 24h, until the seventh day after the beginning of the bioassay. To perform the bioassays with entomopathogenic fungi, B. bassiana and M. anisopliae were obtained from the bio-insecticides Boveril ® WP and Metarril ® WP, respectively and M. rileyi was isolated from H. armigera cadavers at concentration of 10 8 viable conidia/mL. The bioassays were performed using spherical plastic receptacles (2-cmdiameter x 3-cm height) containing artificial diet until complete the half volume. After this step, a solution of 50 µL containing the entomopathogenic fungi was sprayed on the diet surface. One caterpillar was inserted in each receptacle, with less than 24 h after hatch, totaling 100 caterpillars per treatment. Each group containing 10 caterpillars were considered a replication. Mortality were assessed each 24h, until the tenth day after the beginning of the bioassay. First instar caterpillars from the two populations, independent of the Bt-based product showed high mortality when compared to the other instars, with a range between 80 ± 4,22% e 88 ± 3,59%. Most treatments did not show significant difference related to larval mortality to the second, third and fourth instars. The fifth instar showed the lowest mortality to the populations, considering the three commercial biological products. The two H. armigera populations were susceptible to the Bt-based insectcides, and the highest mortality was associated to the first instars. The entomopathogenic fungus M. rileyi caused highest mortality only to the first instar when compared to the other entomopathogens, however, showed the lowest efficiency when compared to the other microbial agents to the other instars.
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SELECTION OF <i>BEAUVERIA BASSIANA</i> (BALSAMO) VUILLEMIN ISOLATES FOR MANAGEMENT OF <i>MYZUS PERSICAE</i> (SULTZAR) (HOM.: APHIDAE) BASED ON VIRULENCE AND GROWTH RELATED CHARACTERISTICS

SELECTION OF <i>BEAUVERIA BASSIANA</i> (BALSAMO) VUILLEMIN ISOLATES FOR MANAGEMENT OF <i>MYZUS PERSICAE</i> (SULTZAR) (HOM.: APHIDAE) BASED ON VIRULENCE AND GROWTH RELATED CHARACTERISTICS

It is well known for entomopathogenic fungal isolates of the same species to exhibit different biological and ecological differences when challenged against the same insect species. Therefore, one of the first important steps in the development of an effective microbial control agent is careful evaluation and selection of the appropriate isolate based on virulence against the target pest. B. bassiana is not an exception in this route of development as many studies involved evaluation of this fungal species against insect pests for further use as a biological control agent (Liu et al., 2003; Quesada- Moraga et al., 2006). Although B. bassianais known to be able to infect the green peach aphid (Alongkorn et al., 2013), very little is known about the virulence of its different isolates against this economically important insect pest. Todorova et al. (2000) evaluated the pathogenicity of 10 B. bassiana isolates against two insect pests, the Colorado potato beetle (Leptinotarsa decemlineata Say) and the green peach aphid (M. persicae) under laboratory conditions. Six out of the ten tested isolates were found highly virulent to the two pests. The current study evaluated 33 different B. bassiana isolates under laboratory and greenhouse conditions where the green peach aphid is considered a major pest for many greenhouse crops.
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Synergy in efficacy of fungal entomopathogens and permethrin against West African insecticide-resistant Anopheles gambiae mosquitoes.

Synergy in efficacy of fungal entomopathogens and permethrin against West African insecticide-resistant Anopheles gambiae mosquitoes.

A growing body of empirical and theoretical studies suggests a potential role for a new class of bio-insecticides based on insect- pathogenic fungi. Several laboratory studies have demonstrated the potential of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana to infect and kill Anopheles, Aedes and Culex mosquitoes [13–23]. Spores (conidia) of these two hyphomycetous fungi can attach to the insect upon contact, whereupon they germinate, penetrate the cuticle, proliferate inside the mosquito body and eventually cause death [24]. The infection process takes several days, usually between 3 and 14 days, with the overall time to death depending mostly on fungal dose and virulence of the isolate [17,20,23]. This mode of infection lends itself to a range of delivery systems. Several application techniques that use either dry or formulated spores on mosquito resting surfaces have been shown to infect and kill the majority of exposed mosquitoes within 7–10 days [16,17,19,25]. Prior to death, fungal infection can also lead to reduced blood-feeding frequency and reproductive fitness [22] and can impact on the development of malaria parasites within the mosquito [21]. Other studies demonstrate low risk of spore applications to human health and the environment [26–28]. With respect to insecticide resistance, an important finding is that candidate fungal pathogens appear equally effective in infecting and killing metabolically resistant anophelines as their susceptible counterparts [18,29]. A recent study showed that fungal impact was higher in a pyrethroid-resistant (kdr) colony of An gambiae s.s. than in an insecticide-susceptible colony [30]. Moreover, infection with Metarhizium or Beauveria increased permethrin and DDT sensitivity in highly resistant laboratory- reared Anopheles mosquitoes originating from Southern and East Africa, which was suggested to have been caused by a reallocation of insecticide-detoxifying enzymes toward fungal toxins [18]. These findings suggest potential for novel integrated vector management strategies that combine conventional and bio- insecticidal tools. Further support for this idea is provided by a recent theoretical study, which demonstrated that control strategies using both fungi and insecticide treated bednets could have greater impact on malaria transmission than control measures based on either intervention alone [31]. Such approach- es could be of particular use in countries like Benin, where high levels of pyrethroid resistance are already threatening the impact of conventional vector control tools [4,32].
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Obtaining and production isolates

Obtaining and production isolates

ABSTRACT: The green mite, Mononychellus tanajoa (Bondar) (Acari: Tetranychidae), is considered to be one of the key pests in cassava, Manihot esculenta Crants, leading to considerable field losses. In this study, ten Beauveria bassiana (Bals.) Vuill. and ten Metarhizium anisopliae (Metsch.) Sorok. isolates were evaluated with regard to their potential as biological control agents against adult M. tanajoa females. The total mortality percentage of M. tanajoa caused by B. bassiana ranged from 13.0 to 97.0%, with confirmed mortality rates extending from 9.0 to 91.0% and LT 50 varying from 4.2 to 17.0 days. The M. anisopliae isolates showed total mortality percentages ranging from 12.0 to 45.0% with confirmed mortality rates extending from 8.0 to 45.0%, and LT 50 varying from 8.6 to 19.8 days. Lethal Concentrations (LC 50 ) of 3.93 × 10 6 conidia mL -1 and
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Patogenicidade de isolados de três fungos entomopatogênicos a soldados de Atta sexdens sexdens (Linnaeus, 1758) (Hymenoptera : Formicidae).

Patogenicidade de isolados de três fungos entomopatogênicos a soldados de Atta sexdens sexdens (Linnaeus, 1758) (Hymenoptera : Formicidae).

ABSTRACT –Leaf-cutting ants attack several crops, pastures and the planted forests, acting on numerous vegetable species. The present work aimed to evaluate the pathogenicity of the fungi Beauveria bassiana (isolates AM 9 and JAB 06), Metarhizium anisopliae (isolates E 9 and Al) and Paecilomyces farinosus (isolates CG 189 and CG 195) against soldiers of Atta sexdens sexdens, in laboratory conditions. These fungi were inoculated on soldiers after collection in nests without pesticides application. Specimens of soldiers were separated in groups of eight insects, which were bathed in suspensions containing 1.0 x 10 6 , 1.0 x 10 7 , 1.0
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Selection of Beauveria bassiana and Metarhizium anisopliae Isolates to Control Triatoma infestans

Selection of Beauveria bassiana and Metarhizium anisopliae Isolates to Control Triatoma infestans

Entomopathogenic fungi are promising candi- dates for microbiological control of Triatominae (Hemiptera, Reduviidae) because they invade their hosts through the integument. However, relative humidity (RH) and temperature are known to be limiting environmental factors for fungal develop- ment on insects (Glare & Milner 1991, Ferron et al. 1991). High rates of infection and a rapid kill of triatomine bugs by the hyphomycete fungi Beauveria bassiana and Metarhizium anisopliae were obtained at humidities close to saturation (Silva & Messias 1985, Romaña & Fargues 1987, Luz 1990, Romaña 1992, Luz et al. 1994). Infec- tion of bugs diminished with B. bassiana at RH below 97% (Luz 1994). Optimal temperatures for fungal development on the insect host range from 16 to 30°C for B. bassiana and M. anisopliae with a faster development at the higher temperatures (Ferron et al. 1991).
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SELECTION OF Metarhizium anisopliae (METSCH.) AND Beauveria bassiana (BALS.) ISOLATES TO CONTROL Alabama argillacea (HUEBNER) CATERPILLARS

SELECTION OF Metarhizium anisopliae (METSCH.) AND Beauveria bassiana (BALS.) ISOLATES TO CONTROL Alabama argillacea (HUEBNER) CATERPILLARS

For B. bassiana, at the concentration of 10 9 conidia mL -1 , mortalities obtained with all isolates were higher than 60%; however, the isolates did not differ statistically from each other, and the highest mortality of A. argillacea caterpillars was observed with isolate 645 (80.7%) (Table 3). These results are similar to those obtained by França et al. (1989) and Faria et al. (1992), when they worked with other B. bassiana isolates and verified high mortalities of S. frugiperda caterpillars. At a concentration of 10 8 conidia mL -1 , according to what was verified during the initial selection phase, isolates caused mortalities over 50%, with isolate 604 being prominent, since it was not different at concentrations of 10 9 and 10 8 conidia mL -1 . At concentrations of 10 7 and 10 6 conidia mL -1 , B. bassiana isolates caused caterpillar mortalities below 40.0 and 25.0%, respectively, which are levels similar to those recorded by Rodrigues & Pratissoli (1989) when they applied B. bassiana at the concentration of 10 7 conidia mL -1 against S. frugiperda caterpillars, observing mortality levels of 40.0%.
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