ABSTRACT
ABSTRACT: Increased production of the Cape gooseberry (Physalis peruviana L.) in Brazil has given rise to interest in identifying the phytophagous species that might damage this crop to inform preventive control and integrated pest management strategies. In this study, we report the occurrence and describe the damage that larvae and adults of Lema bilineata Germar (Coleoptera: Chrysomelidae) cause in P. peruviana. The number of L. bilineata individuals, both larvae and adults, significantly affected the total consumption of P. peruviana leaves. We also report, for the first time, three natural enemies, including a fungus, a fly, and an ant, which are associated with this pest in Brazil and may play a role in biological control strategies.
RESUMO: Fisális, Physalis peruviana L., é uma cultura em expansão no Brasil, dessa forma a identificação de espécies fitófagas que causam danos nesta cultura é importante para desenvolver controle preventivo e estratégias para o Manejo Integrado de Pragas. Neste estudo, relatamos a ocorrência de Lema bilineata Germar (Coleoptera: Chrysomelidae) no cultivo de P. peruviana e descrevemos os danos causados por suas larvas e adultos. Observou-se que o número de indivíduos de L. bilineata, tanto larvas como adultos, influenciaram significativamente o consumo total de folhas de P. peruviana. Além disso, relatamos pela primeira vez a presença de três inimigos naturais, incluindo um fungo, uma mosca e uma formiga, associados a esta praga no Brasil que poderiam ser utilizados como agentes de controle biológico.
ABSTRACT
Aims@#Metarhizium anisopliae is an entomopathogenic fungus (EPF) that exists naturally in the environment and potentially be used as a biological control agent against many insect pests. This study aims to evaluate the effect of nutrient additives on the yield and viability of M. anisopliae spore and to determine the optimum incubation period for maximum spore production.@*Methodology and results@# In this study, M. anisopliae was cultivated by solid-state fermentation using rice as a growth medium. Three different nutrient additives were examined which aimed to maximize the production of M. anisopliae spores. Among the three nutrient additives evaluated, yeast (1.84 ± 0.04 g) supported better growth and spore production than molasses (0.58 ± 0.04 g) and palm oil (0.47 ± 0.09 g). The incubation period between 2-6 weeks produced higher spore yield (0.97 ± 0.02 g spores) at week 4 with a better spore viability (86.30 ± 0.45%) at week 2. @*Conclusion, significance and impact of study@#Hence, it is suggested that the optimum incubation period is between 2 and 6 weeks after inoculation, and M. anisopliae could be mass produced in large quantities on rice substrate with the addition of yeast as the nutrient additives.
Subject(s)
Biological Control Agents , Microbial Viability , MetarhiziumABSTRACT
@#Rhipicephalus sanguineus, commonly known as brown dog tick is a widespread species with considerable public health and economic importance. Tremendous efforts were performed to control the tick populations with the concern of resistance build-up and environmental issues. Alternative towards microbial control thus emerged as one option to reduce tick populations. In this study, the ovicidal efficacy of a native isolate entomopathogenic hyphomycetes fungi, Metarhizium anisopliae strain HSAH5 was evaluated against eggs of R. sanguineus. Spray applications with three different conidial concentrations of 105, 106 and 107 conidia mL-1; 40 ppm of Flumethrin and a negative control. The M. anisopliae strain was found highly virulent to R. sanguineus eggs by reducing the hatching percentages to ≈30% compared with 8.9% in Flumethrin eggs. The result showed a significantly higher mortality in M. anisopliae group than those of the control groups (F = 42.08, df = 32, P < 0.001) at 30 days post-infection. However, there are no significant differences within the M. anisopliae group, in which the mortality between different conidial concentrations is almost the same. The estimated LC50 of M. anisopliae against eggs of R. sanguineus is 1.36 × 103 conidia ml-1. Thus, these results suggest M. anisopliae strain HSAH5 could be a potential biocontrol agent of R. sanguineus in the integrated approach to managing ticks in the residential landscape by targeting on the eggs.
ABSTRACT
Beauveria bassiana belongs to the class Deuteromycetes which is one of the important disease-causing biocontrol agents in insects. B. bassiana, formerly known as Botrytis bassiana (Balsamo), is a widely distributed soil inhabiting fungus. B. bassiana is also known to be best biocontrol agent against larval stage of the silkworm. B. bassiana is categorized as a white muscardine fungus due to the white color of sporulating colonies. It is a type of biopesticide which is based on entomopathogenic fungi which are often considerable scope as plant protection agents against several pathogens and insects including whiteflies, aphids, thrips, grasshoppers, and certain types of beetles. The present study deals with the use of different media such as coconut media, jaggery media, nutrient media, potato dextrose media, Sabouraud dextrose media, and molasses media
ABSTRACT
Abstract Beauveria bassiana is a promising fungus for the biological control of insect pests. The growing costs of conidia production have raised the need to ascertain the efficiency of some low cost substrates. The aim of this study was to analyze the potential use of different raw substrates without nutritional supplement for B. bassiana conidiogenesis. Growth and sporulation were evaluated using 30 g of substrate and 0.3 μL of a conidia suspension (1 x 106 conidia/mL). After 10 days of incubation (70 ± 10% humidity and temperature (T) = 29 ± 1 °C), rice (2.00 x 106 conidia/g substrate), algaroba (2.36 x 106 conidia/g), malt A (1.22 x 106 conidia/g) and malt B (1.75 x 106 conidia/g) showed the highest levels of conidia production. The resulting conidia showed insecticidal activity higher than 80% on coconut termites. These new raw substrates may represent viable alternatives for the production of entomopathogenic fungi for use in the biological control of various insect pests.
Resumo Beauveria bassiana é um fungo promissor no controle biológico de insetos-praga. As crescentes despesas na produção de conídios levantam a necessidade de averiguar a eficiência de alguns substratos de baixo custo. O objetivo deste trabalho foi analisar o potencial de utilização de diferentes substratos brutos para a conidiogênese de B. bassiana. O crescimento e esporulação foram realizados utilizando 30 g do substrato e 0,3 µL da suspensão de conídios (1 x 106 conídios/mL). Após 10 dias de incubação (umidade 70 ± 10% e temperatura T = 29 ± 1° C), o arroz (2,00 x 106 conídios/g de substrato), algaroba (2,36 x 106 conídios/g), malte A (1,22 x 106 conídios/g) e B (1,75 x 106 conídios/g), apresentaram maior produção de conídios. Os conídios produzidos mostraram atividade inseticida sobre o cupim do coqueiro acima de 80% de mortalidade. Estes novos substratos brutos podem representar uma alternativa viável para produção de fungos entomopatogênicos para uso no controle biológico de vários insetos praga.
Subject(s)
Mitosporic Fungi , Beauveria , Spores, Fungal , Pest Control, Biological , HumidityABSTRACT
Abstract The effects of two different products - Metarril® SP Organic (dry conidia) and Metarril® SC Organic (emulsifiable concentrated conidia in vegetable oil) - on eggs, larvae and Rhipicephalus microplus engorged females were here explored. Three concentrations (108, 107, and 106 conidia mL-1) for both products were prepared in water + 0.1% Tween® 80 (v/v); afterward, bioassays were carried out for all R. microplus stages by immersion in suspensions (Metarril® SP) or formulations (Metarril® SC). Metarril® SP suspensions showed low efficacy and did not affect biological parameters of treated engorged females; for eggs and larvae, only slight decreases in hatchability and larvae population were observed. Despite a delay in germination, Metarril® SC presented better results; for females, reductions in Egg Mass Weight (EMW) and Egg Production Index (EPI) were reported. On eggs, 108 conidia mL-1 increased Incubation Period (IP), shortened Hatching Period (HP) and decreased hatchability by up to 61%; for larvae, 107 and 108 conidia mL-1 reached 99.6 and 100% larval mortality respectively, 10 days after fungal exposure. Thus, further studies involving the use of oil-based formulations for ticks such as Metarril® SC need to be performed, especially to control the most susceptible stages (eggs and larvae).
Resumo No presente trabalho, os efeitos de dois diferentes produtos foram avaliados - Metarril® SP Organic (conídios secos) e Metarril® SC Organic (conídios concentrados em óleo vegetal) - para ovos, larvas e fêmeas ingurgitadas de Rhipicephalus microplus. Três concentrações (108, 107 e 106 conídios mL-1) para cada produto foram preparadas em água + Tween® 80 0,1% (v/v); os bioensaios foram realizados para todos os estágios de R. microplus por imersão nas suspensões (Metarril® SP) ou formulações (Metarril® SC). Metarril® SP não afetou os parâmetros biológicos das fêmeas, demonstrando assim baixa eficácia; para ovos e larvas, foram observadas discretas diminuições na eclodibilidade e na população de larvas. Apesar de um atraso na germinação, Metarril® SC apresentou melhores resultados; para as fêmeas, foram detectadas reduções no Peso da Massa de Ovos (PMO) e no Índice de Produção de Ovos (IPO). Para os ovos, a concentração de 108 conídios mL-1 aumentou o Período de Incubação (PI), reduziu o Período de Eclosão (PE) e também o da eclodibilidade em até 61%; para larvas, 107 e 108 conídios mL-1 atingiram 99,6 e 100% de mortalidade larval, respectivamente, 10 dias após a exposição fúngica. Com isso, estudos adicionais que envolvem o uso de formulações à base de óleo para carrapatos, como Metarril® SC, precisam ser realizados, especialmente para controlar os estágios mais suscetíveis (ovos e larvas).
Subject(s)
Animals , Female , Pest Control, Biological , Tick Control/methods , Tick Control/standards , Rhipicephalus/microbiology , Metarhizium , LarvaABSTRACT
The aim of this study was to analyze the compatibility of the Metarhizium anisopliae JAB 68 isolate with liposoluble photoprotectants and the photoprotection conferred to its conidia. The fungus was cultivated in a medium with the photoprotectants Neo Heliopan® BB, Neo Heliopan® E 1000, Eusolex® 6007 and Neo Heliopan® AV in various concentrations. Vegetative growth, sporulation and germination were assessed to determine compatibility. Then, conidia were suspended in oil containing the compatible photoprotectants, in their respective concentrations, and exposed to 0-7 hours of light from a solar simulator operating at 1,000 W m-2. Neo Heliopan BB® and Neo Heliopan® E 1000 were compatible with M. anisopliae at 2% and 1%, respectively. Eusolex® 6007 and Neo Heliopan® AV were compatible up to 8% a 7%, respectively. Conidia exposed to radiation from the solar simulator, with photoprotectant-free oil as its carrier, presented germination of 78.12% after five hours. When adding any photoprotectant to the conidia oily suspension, the germination percentage was always higher than that obtained in the control. Neo Heliopan® BB at 1 and 2% and Neo Heliopan® AV at 0.5% increased the germination. After 7 hours of exposure the germination percentages were 93.77, 94.55 and 98.82%, respectively. Eusolex® 6007 was not as efficient as previous products, but in the same exposure period was able to protect the conidia (88.60% germination) when used at a 1% concentration. Adding photoprotectants in oily formulations of M. anisopliae protects against the harmful effects of UV radiation contributing to the fungus efficiency in the field.
O objetivo desse trabalho foi analisar a compatibilidade do isolado JAB 68 de Metarhizium anisopliae com fotoprotetores lipossolúveis e a fotoproteção conferida aos seus conídios. O fungo foi cultivado em meio contendo os fotoprotetores Neo Heliopan® BB, Neo Heliopan® E 1000, Eusolex® 6007, Neo Heliopan® AV em várias concentrações. O crescimento vegetativo, a esporulação e a germinação foram avaliados para determinar a compatibilidade. Conídios foram suspensos em óleo contendo os fotoprotetores compatíveis, em suas respectivas concentrações, e submetidos por 0 a 7 horas à luz de um simulador solar na potência de 1.000W m-2. Neo Heliopan BB® e Neo Heliopan® E 1000 foram compatíveis com M. anisopliae à 2% e 1%, respectivamente. Eusolex® 6007 e Neo Heliopan® AV foram compatíveis até 8% e 7%, respectivamente. Conídios de M. anisopliae expostos à radiação do simulador solar, tendo óleo isento de fotoprotetor como veículo, apresentaram germinação de 78,12% após cinco horas. Adicionando-se qualquer fotoprotetor à suspensão oleosa de conídios a porcentagem de germinação foi sempre maior que a obtida no controle. Neo Heliopan® BB a 1 e 2% e Neo Heliopan® AV a 0,5% incrementaram a germinação. Após 7 horas de exposição as porcentagens de germinação foram de 93,77, 94,55 e 98,82%, respectivamente. Eusolex® 6007 não foi tão eficiente quanto os produtos anteriores, mas no mesmo período de exposição foi capaz de proteger os conídios (88,60% de germinação) quando usado na concentração de 1%. A adição de fotoprotetores em formulações oleosas de M. anisopliae confere proteção aos raios UV, contribuindo com a eficiência do fungo no campo.
Subject(s)
Spores, Fungal , Sunlight , Ultraviolet Rays , Pest Control, Biological , Metarhizium , FungiABSTRACT
Abstract Beauveria bassiana is a promising fungus for the biological control of insect pests. The growing costs of conidia production have raised the need to ascertain the efficiency of some low cost substrates. The aim of this study was to analyze the potential use of different raw substrates without nutritional supplement for B. bassiana conidiogenesis. Growth and sporulation were evaluated using 30 g of substrate and 0.3 L of a conidia suspension (1 x 106 conidia/mL). After 10 days of incubation (70 ± 10% humidity and temperature (T) = 29 ± 1 °C), rice (2.00 x 106 conidia/g substrate), algaroba (2.36 x 106 conidia/g), malt A (1.22 x 106 conidia/g) and malt B (1.75 x 106 conidia/g) showed the highest levels of conidia production. The resulting conidia showed insecticidal activity higher than 80% on coconut termites. These new raw substrates may represent viable alternatives for the production of entomopathogenic fungi for use in the biological control of various insect pests.
Resumo Beauveria bassiana é um fungo promissor no controle biológico de insetos-praga. As crescentes despesas na produção de conídios levantam a necessidade de averiguar a eficiência de alguns substratos de baixo custo. O objetivo deste trabalho foi analisar o potencial de utilização de diferentes substratos brutos para a conidiogênese de B. bassiana. O crescimento e esporulação foram realizados utilizando 30 g do substrato e 0,3 µL da suspensão de conídios (1 x 106 conídios/mL). Após 10 dias de incubação (umidade 70 ± 10% e temperatura T = 29 ± 1° C), o arroz (2,00 x 106 conídios/g de substrato), algaroba (2,36 x 106 conídios/g), malte A (1,22 x 106 conídios/g) e B (1,75 x 106 conídios/g), apresentaram maior produção de conídios. Os conídios produzidos mostraram atividade inseticida sobre o cupim do coqueiro acima de 80% de mortalidade. Estes novos substratos brutos podem representar uma alternativa viável para produção de fungos entomopatogênicos para uso no controle biológico de vários insetos praga.
ABSTRACT
This study aimed to evaluate the in vitro effect of homeopathic solutions Arsenicum Album 24CH; Calcarea carbonica 30CH; Kali iodatum 100CH;Phosphorus 3CH; Silicea 30CH; Staphysagria 6, 30 and 100CH; Spodoptera frugiperda 30CH; Sulphur 100 and 200CH and Thuya occidentalis 200CH on biological parameters of the fungus Metarhizium anisopliae . The solutions were diluted in sterile distilled water (0.1%) and were sprayed on the previously inoculated fungus on PDA culture medium. Germination, colony forming units, vegetative growth, conidial production and insecticidal activity of the fungus against larvae of Diatraea saccharalis (Lepidoptera: Crambidae) were evaluated. Homeopathic solutions did not affect negatively the parameters evaluated. Thus, all treatments were considered compatible to the fungus M. anisopliae.(AU)
O presente trabalho teve por objetivo avaliar o efeito in vitro das soluções homeopáticas Arsenicum album 24CH;Calcarea carbonica 30CH; Kali iodatum100CH; Phosphorus 3CH; Silicea 30CH; Staphysagria 6, 30 e 100CH; Spodoptera frugiperda 30CH; Sulphur 100 e 200CH eThuya occidentalis 200CH sobre parâmetros biológicos do fungo Metarhizium anisopliae. As soluções medicamentosas foram diluídas em água destilada (esterilizada) (0,1%) e pulverizadas sobre o fungo previamente inoculado no meio de cultura BDA. Os parâmetros biológicos avaliados foram: germinação de conídios, unidades formadoras de colônias, crescimento vegetativo, produção de conídios e atividade inseticida contra lagartas de Diatraea saccharalis (Lepidoptera: Crambidae). As soluções não afetaram os parâmetros avaliados. Todos os tratamentos foram considerados compatíveis ao M. anisopliae .(AU)
Subject(s)
Arsenicum Album , Calcarea Carbonica , Kali Iodatum , Hydroalcoholic Solution , Metarhizium , Fungi , Homeopathic Remedy , Pest Control , InsectaABSTRACT
O objetivo deste estudo foi registrar a primeira ocorrência natural e patogenicidade da associação entre Beauveria bassiana e Protortonia navesi na cultura da mandioca. Para isso, ninfas e adultos de P. navesi infectados foram coletados em amostragens realizadas quinzenalmente, na área do Instituto Agronômico do Paraná, em Marechal Cândido Rondon, de janeiro a dezembro de 2012. Amostras foram analisadas e, utilizando-se meio de cultura seletivo de aveia, foi isolado o fungo a partir dos cadáveres, sendo identificado como Beauveria bassiana (Bals.) Vuill., armazenado na Coleção de Fungos Entomopatogênicos do Laboratório de Biotecnologia Agrícola, sob o código Unioeste 78. Para comprovar sua patogenicidade, foi adotado o postulado de Koch, aplicando-se o fungo (10 9 conídios/mL) sobre ninfas e adultos de P. navesi obtidos da criação de laboratório. Após 10 dias de incubação, verificou-se 18% de mortalidade confirmada, sendo considerada baixa a atividade sobre a cochonilha P navesi.(AU)
The objective of this study was to record the first natural occurrence and pathogenicity of the association between Beauveria bassiana and Protortonia navesi in the cassava crop. Infected P. navesi nymphs and adults were collected in samples fortnightly in the Agronomic Institute of Paraná, in Marechal Cândido Rondon, from January to December 2012. Samples were analyzed at the Laboratory of Agricultural Biotechnology. The entomopathogenic fungus was isolated from corpses using selective oatmeal culture medium, and multiplied for sporulation being identified as Beauveria bassiana (Bals.) Vuill. The fungus was stored in the Collection of Entomopathogenic Fungi Laboratory of Agricultural Biotechnology, identified as Unioeste 78. To prove the pathogenicity of the found isolate, bioassays were performed following the postulate of Koch, the fungi suspension was sprayed (10 9 conídios mL), on nymphs and adults of P. navesi obtained from laboratory rearing. After 10 days of incubation there was 18% mortality confirmed, being considered low activity on mealybugs Protortonia.(AU)
Subject(s)
Virulence , Manihot , Pest Control, Biological , Beauveria/pathogenicity , HemipteraABSTRACT
Se caracterizaron tres fermentadores: New Brunswick M-19 de 14 litros, Applikon Biocontroller 1035 de 7 litros y New Brunswick Bioflo III de 7 litros, determinando el coeficiente volumétrico de transferencia de oxígeno (KLa), la retención de gas (RG) y el tiempo de mezclado (tM). El fermentador New Brunswick Bioflo III tuvo los mejores valores con una relación de diámetro del impulsor/diámetro del tanque (DI/DT) de 0.43, KLa = 9.5-208 h-1 y tM = 1.0-3.0 s, por lo que fue seleccionado para realizar la producción de blastosporas de Beauveria bassiana, utilizando melaza como fuente de carbono. Se estudiaron las condiciones de mezclado, utilizando diferentes combinaciones de impulsores tipo Rushton, Maxflo y Lightnin, bajo un diseño experimental factorial 32. El tiempo de propagación fue de 4 días, el volumen de trabajo 4 litros, 10% de inóculo (1x106 blastosporas/ml), temperatura 30°C, agitación de 400-500 rpm, aireación de 0.5-1.0 vvm, y pH de 5.4.El hongo se desarrolló mejor utilizando la combinación de impulsores Rushton-Maxflo a 400 rpm y 1.0 vvm (F = 10.324, p ≤ 0.0123) (DMS=0.585), obteniendo una concentración de 1.2x109 blastosporas/ml, 2.2 g/l de biomasa y 2.48 g/l de consumo de sustrato (Y x/s=0.89). Las condiciones de mezclado y los parámetros obtenidos pueden ser aplicados en otros fermentadores para optimizar la producción de blastosporas de B. bassiana en la elaboración experimental de bioinsecticidas.
In this work three fermenters were characterized: New Brunswick M-19 of 14 liters, Biocontroller Applikon 1035 of 7 liters and New Brunswick Bioflo III of 7 liters, determining the volumetric coefficient oxygen transfer (KLa), gas hold up (GH) and the mixing time (tM). The fermenter New Brunswick Bioflo III had the best values with a ratio of diameter of the impeller/vessel (DI/DT) of 0.43, KLa = 9.5-208 h-1 and tM = 1.0-3.0 s, so it was selected for the production of blastospores of Beauveria bassiana, using molasses as carbon source. We studied the mixing conditions, using different combinations of impellers, type Rushton, Lightnin and Maxflo under a factorial experimental design 32. The propagation time was of 4 days, working volume 4l, 10% inoculum (1x106 blastospores/ml), temperature 30°C, agitation of 400-500 rpm, aeration 0.5-1.0 vvm, and pH of 5.4. The fungus growth better using a combination of impellers Rushton-Maxflo at 400 rpm and 1.0 vvm (F = 10.324, p ≤ 0.0123) (LSD = 0.585) obtaining a concentration of 1.2x109 blastospores/ml, 2.2 g/l biomass and 2.48 g/l of substrate consumption (Y x/s = 0.89). The mixing conditions and the parameters obtained can be applied to optimize the blastospore productions of B. bassiana to fermenter level in the experimental production of bioinsecticides.
Subject(s)
Aeration , Beauveria , Fermentation , InsecticidesABSTRACT
The aim of this work was to evaluate the effect of temperature on the pathogenicity of Beauveria bassiana against Diatraea saccharalis and evaluate the horizontal transmission capacity among the sugarcane borer larvae. The strains were most pathogenic at 26ºC, followed by 32ºC than at 20ºC, with respective mortalities of 100, 50 and 30.3%. The lethal time was also affected by the temperature, with the shortest LT 50 observed at 26ºC (2.2 days) and the longest at 20ºC (16.2 days). The URM2915 strain appeared most effective in all the experiments as having potential for deployment in biological control programs for the sugarcane borer. Results in horizontal transmission of B. bassiana showed that this procedure could also be adopted as control strategy for the sugarcane borer.
ABSTRACT
Objective: To isolate the entomopathogenic fungus Metarhizium anisopliae (M. anisopliae) in the local environment, and evaluate its efficacy against the suspected dengue vector Aedes albopictus in Pakistan. Methods: According to the standard procedure, M. anisopliae was isolated from the dead mosquitoes which were collected from the field or dead after the collection. Bioassay was performed to determine its efficacy. Results: The results indicated that M. anisopliae had larvicidal effect with LC50 value 1.09×105 and LC90 value 1.90×1013 while it took 45.41 h to kill 50%of tested population. Conclusions: Taking long time to kill 50% population when compare with the synthetic insecticides, is the only drawback for the use of entomopathogenic fungus but these bio-pesticides are safe for the use.
ABSTRACT
The pigeon tick Argas reflexus is a pathogen-transmitting soft tick that typically feeds on pigeons, but can also attack humans causing local and systemic reactions. Chemical control is made difficult due to environmental contamination and resistance development. As a result, there is much interest in increasing the role of other strategies like biological control. In this study, the efficacy of three strains (V245, 685 and 715C) of entomopathogenic fungus Metarhizium anisopliae for biological control of three life stages of pigeon tick A. reflexus including eggs, larvae, engorged and unfed adults was investigated under laboratory conditions. Five concentrations of different strains of M. anisopliae ranging from 10³ to 10(7) conidia/ml were used. All fungal strains significantly decreased hatchability of A. reflexus eggs. Strain V245 was the most effective strain on the mortality of larval stage with nearly 100 percent mortality at the lowest concentration (10³ conidia/ml) at 10 days post-inoculation. The mortality rate of both engorged and unfed adult ticks were also increased significantly exposed to different conidial concentrations compared to the control groups (P < 0.05) making this fungus a potential biological control agent of pigeon tick reducing the use of chemical acaricides.
Subject(s)
Animals , Argas/pathogenicity , Argasidae/pathogenicity , Columbidae , Entomophthora/isolation & purification , Fungi/pathogenicity , Pest Control, Biological , Tick Infestations , Methods , Methods , Veterinary Medicine , VirulenceSubject(s)
Animals , Beauveria , Brassica/parasitology , Pest Control, Biological/methods , Aphids/microbiologyABSTRACT
Se realizó un estudio para indagar aspectos histopatológicos y ultraestructurales de la interacción entre un aislamiento nativo (LF14) del hongo entomopatógeno Beauveria bassiana (Ascomycota, Hypocreales) y ninfas de quinto estadio y adultos de Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae). En los primeros estadios de la infección se observaron las conidias adheridas al exoesqueleto y en el momento de su penetración del tubo germinal. Después de la penetración vía tegumento y traqueolas del hemocele, las hifas invadieron virtualmente todos los tejidos y órganos, con el subsiguiente fallecimiento del insecto. En el último estadio del proceso infeccioso, se detectó la infección masiva del hifomiceto penetrando todo el cuerpo de adentro hacia aberturas del tegumento, para finalmente esporular, observándose numerosos conidios desprendidos de los conidióforos. La Microscopía Electrónica de Transmisión (MET) reveló una invasión masiva de hifas y micelios fúngicos en todo el hemocele, con hemocitos fagocitando, encapsulando y melanizando al hongo. Durante la penetración tisular y tegumentaria de las hifas, se observan áreas electrotransparentes que sugieren actividad enzimática.
A histopathological and ultrastructural study was used to describe the mode of interaction between a native isolate (LF14) of entomopathogenic fungus Beauveria bassiana (Ascomycota, Hypocreales) and nymphs/adults of Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae). Conidia germinate on the surface of triatomine bugs and immediately begin penetration of the cuticle and spiracles by germinal tube. Once invade the haemocele, the fungus multiplies extensively whole insect tissues and organs, leading to triatomine death. When insect cadaver is in mummification stage, outgrowths of fungal hyphae occur first and most extensively in the intersegmental regions of triatomines, emerging at the surface, where they initiate sporulation process. Electron Transmission Microscopy (ETM) studies revealed abundant growth of fungal hypahe and micelar into haemocele, with haemocytic infiltration during fagocitation, encapsulation and melanization process of fungal structures. Areas of low electron-density were frequently observed, suggesting the secretion of enzymes by hyphae to weaken and penetrating cuticle and tissues.
Subject(s)
Humans , Animals , Beauveria/growth & development , Beauveria/immunology , Beauveria/pathogenicity , Beauveria/virology , Fungi/pathogenicity , Triatominae/pathogenicity , Triatominae/virology , Pest Control, Biological , Public HealthABSTRACT
In order to assess the effectiveness of Metarhizium anisopliae var. anisopliae (Metschnikoff) Sorokin isolates in controlling the sugarcane root spittlebug Mahanarva fimbriolata (Stal) (Hemiptera: Cercopidae), nine isolates obtained from a single geographical region were studied. 'Confirmed cumulative' and 'corrected cumulative' spittlebug mortality rates were measured for each of the isolates. Based on the confirmed mortality curve, the isolates URM5946, URM5951 and URM6033 were considered to be potentially the most effective in a biological control program for M. fimbriolata.
ABSTRACT
Se hace una revisión sobre el uso e implementación de los hongos entomopatógenos para el control de poblaciones triatominas, vectores del Trypanosoma cruzi. Los estudios muestran que el rociamiento intradomiciliar con insecticidas químicos representa una medida de control práctica y efectiva contra las poblaciones triatominas; no obstante, potencialmente representa un peligro para la salud pública y los ecosistemas, y su uso constante induce a mecanismos de resistencia en TRIATOMINAE. Como alternativa a los insecticidas químicos, se ha venido implementando tanto a nivel experimental como de campo, con resultados esperanzadores, la aplicación de formulaciones fúngicas contra triatominos, los cuales son más inocuos para los vertebrados. Las conidias de los hifomicetos penetran por el tegumento sobre los insectos hematófagos, tal como ocurre con las de Beauveria bassiana sobre los triatominos. En los aislamientos venezolanos se requieren de mayores estudios para dilucidar las clases de metabolitos secundarios presentes y en qué cantidades, de manera tal de poder utilizarlos en programas de control de vectores. En general, obstensiblemente es poco lo que se ha hecho sobre el empleo de especies de hifomicetos nativos contra TRIATOMINAE de Venezuela. Uno de los más estudiados es el aislamiento B. bassiana LF14, el cual ha mostrado ser altamente patógeno y virulento para Rhodnius prolixus y Triatoma maculata, especialmente en formulaciones aceitosas, siendo un patotipo que muestra una excelente adaptabilidad en su capacidad de germinación y esporulación y patogenicidad a las condiciones extremas del trópico venezolano. Los estudios histopatológicos y ultraestructurales confirmaron que sus conidias penetran vía tegumento a TRIATOMINAE.
A revision have been made on the use and implementation of entomopathogenic fungus as triatomine populations control agents, vectors of Trypanosoma cruzi. Studies show that chemical insecticides applied indoors remains as a practical and effective tool for managing triatomine bug populations; nevertheless, insecticides constitute a potential risk to public health and ecosystems, and its intensive use can be induced to insecticide resistance mechanisms in TRIATOMINAE. As a non toxic alternative to chemical insecticides, fungus formulations against triatomines has been implemented in the laboratory as well as in the field-based research conditions, with results considered very optimistic, being safer for vertebrates. Fungal conidia penetrate primarily integument of blood sucking insects, such as by Beauveria bassiana on triatomines. As an attempt to be applied eventually in vector control trials, fungal secondary metabolites need to be precised and cuantified in the venezuelan isolates. Studies for implementation of native hyphomicete species against TRIATOMINAE from Venezuela, is quite limited. Isolate of B. bassiana LF14 has been widely surveyed, showing highly pathogenic and virulent to Rhodnius prolixus and Triatoma maculata, specially in aqueous oil formulations. This patotype showed a high level of tolerante in its germination, sporulation and pathogenicity status for a wide range of venezuelan environmental stressant conditions. Its conidia penetrating cuticle was corfirmed by means of histopathological and ultrastructural studies.
Subject(s)
Pest Control, Biological/methods , Chagas Disease/therapy , Fungi , Triatominae , Disease VectorsABSTRACT
Este estudo teve o objetivo de selecionar isolados do fungo entomopatogênico Metarhizium anisopliae para o controle de adultos de Rhynchophorus palmarum (L.) (Coleoptera: Curculionidae) e avaliar a compatibilidade de agrotóxicos utilizados nesta cultura com o isolado que ocasionasse maior mortalidade dos adultos. Para tal, adultos do inseto foram imersos em suspensões de seis isolados do fungo na concentração de 109 conídios.mL-1 e, após 24 dias, o isolado IBCB 348 causou maior mortalidade (87,5%) e foi utilizado para o teste de compatilibidade, por meio do cálculo da fórmula de T, com inseticidas, herbicidas e fungicidas comerciais utilizados na cultura. Nenhum dos fungicidas e herbicidas testados foram compatíveis com o patógeno. Os inseticidas Calypso, Dipterex 500 e Sevin 480 SC, na concentração mínima recomendada pelo fabricante, foram os únicos produtos classificados como compatíveis com o isolado IBCB 348 de M. anisopliae.
This study was aimed to screen the entomopathogenic fungus Metarhizium anisopliae for the control of Rhynchophorus palmarum (L.) (Coleoptera: Curculionidae) adults and to evaluate the compatibility of agrochemicals used in this crop with the strain that caused the highest insect mortality. To this end, adult insects were immersed in suspensions of 6 strains at a concentration of 109 conidia.mL-1, and after 24 days the isolate IBCB 348 caused the highest mortality (87.5%) and was used in the compatibility test, using calculations by way of the T formula, with commercial insecticides, herbicides and fungicides used in the crop. Among the tested strains, IBCB 348 was the most efficient in the control of this pest, causing 87.5% of weevil mortality. None of the tested fungicides and herbicides were compatible with the pathogen. The insecticides Calypso, Dipterex 500 and Sevin 480 SC, at the lowest dose recommended by the manufacturer, were the only products classified as compatible with the strain IBCB 348 of M. anisopliae.
Subject(s)
Coleoptera , Pest Control, Biological/methods , Musa/parasitology , Metarhizium , Pesticides/analysisABSTRACT
O presente trabalho teve por objetivo avaliar a patogenicidade e a virulência do isolado IBCB66 de Beauveria bassiana para larvas de Rhipicephalus (Boophilus) microplus. O isolado IBCB66 foi utilizado como padrão, com a finalidade de determinar a CL50 (Concentração Letal), CL90, TL50 (Tempo Letal) e TL90. O isolado IBCB66 foi testado em seis concentrações diferentes (5 × 10(6), 10(7), 5 × 10(7), 10(8), 5 × 10(8) e 10(9)) para determinar a porcentagem de mortalidade. A mortalidade total de larvas foi observada 18 dias após o início do teste no grupo tratado com 5 × 10(9) conídios.mL-1. A análise de Probit dos dados consignados apontou a CL50 e CL90 concentrações de 3 × 10(7) e 5 × 10(8) conídios.mL-1 e para TL50 e TL90, foram 10 e 16 dias, respectivamente.
The objective of this research was to evaluate the pathogenicity and the virulence of the IBCB66 isolate of Beauveria bassiana on infected larvae of Rhipicephalus (Boophilus) microplus. The IBCB66 fungus strain was used as standard isolates of B. bassiana against R. (B.) microplus larvae. The larval bioassay tests using the IBCB66 isolate were carried out to determine the (Lethal Concentration) LC50, LC90, (Lethal Time) LT50 and LT90. The IBCB66 fungus strain was tested at six different concentrations (5 × 10(6), 10(7), 5 × 10(7), 10(8), 5 × 10(8) and 10(9) conidia.mL-1) to determine the percentage of larval mortality. In addition, a Probit analysis was also performed. Total larval mortality was observed eighteen days after the beginning of the test in the group treated with 5 × 10(9) conidia.mL-1. The LC50 and LC90 were 3 × 10(7) and 5 × 10(8) respectively and the LT50 and LT90 were 10 and 16 days.