ABSTRACT The cornstalk borer, Elasmopalpus lignosellus (Lepidoptera: Pyralidae), reduces the productive potential of maize crops and is a difficult pest to manage. A management program using different methods could improve the control of E. lignosellus. Considering the potential of entomopathogenic nematodes (EPN) in reducing insect pest populations in soil, the objective of this study was to evaluate the virulence of these EPN and adjust their concentration for controlling E. lignosellus larvae under laboratory and greenhouse conditions. In the laboratory, the virulence of five EPN populations was tested; then, Heterorhabditis amazonensis MC01 was tested at four concentrations. In the greenhouse, H. amazonensis MC01 was tested at four concentrations and was applied to vessels containing maize plants and six larvae. After five days, mortality was evaluated, and means were compared using Tukey’s test (p-value < 0.05). Heterorhabditis amazonensis MC01 and S. carpocapsae All were equally virulent, reducing the larva population by more than 90%. The concentration of H. amazonensis MC01 that caused the highest mortality of larvae in the laboratory was 182 infective juveniles (IJ) larva-1. In the greenhouse, the nematode was also considered virulent to E. lignosellus since all concentrations tested caused larval mortality greater than 70%. borer Lepidoptera (Lepidoptera Pyralidae, Pyralidae , Pyralidae) manage E (EPN soil conditions then MC MC0 H days evaluated Tukeys Tukey s pvalue p value 0.05. 005 0.05 . 0 05 0.05) S 90 90% 18 IJ (IJ larva1. larva1 1. 1 larva-1 70 70% 00 0.0 9 larva- 7 0.

RESUMO O uso da fenotipagem por imagens apresenta alto potencial para avaliação de experimentos na cultura do tomateiro. Validar a aplicação desse método é importante par reduzir custos e tempo. Assim, a pesquisa teve como objetivo investigar o desempenho agronômico de híbridos e linhagens de tomateiro a partir de índices de vegetação. Foi utilizado o delineamento em blocos casualizados com três repetições. Foram avaliados 36 híbridos experimentais e 9 linhagens, além do genitor recorrente UFU-57 e um híbrido comercial, totalizando 47 tratamentos. Foram avaliados o peso médio, diâmetro transversal e longitudinal, espessura da polpa, número de lóculos, teores de sólidos solúveis, β-caroteno e licopeno. Além disso, analisou-se o desenvolvimento vegetativo da planta por meio de índices de vegetação obtidos com o suporte de uma aeronave e remotamente pilotada. Os dados foram analisados por meio de teste de média e análise multivariada e demonstraram que índices de vegetação podem ser capazes de distinguir linhagens dos híbridos e que o uso de imagens, para avaliação do germoplasma de tomateiro, pode auxiliar em futuras fenotipagens. tempo Assim repetições 3 UFU57 UFU 57 UFU-5 comercial 4 tratamentos médio longitudinal polpa lóculos solúveis βcaroteno β caroteno licopeno disso analisouse analisou se pilotada fenotipagens UFU5 5 UFU-

ABSTRACT Image phenotyping presents great potential for field experiment evaluations in tomato crop. Validating this method for tomato plants is important to reduce costs and time. Thus, the objective of the present study is to investigate the agronomic performance of tomato hybrids and inbred lines using vegetation index. A randomized block design with three replications was used. A total of36 experimental hybrids and 9 inbred lines were evaluated, in addition to the recurrent genitor UFU-57 and a commercial hybrid, culminating in 47 treatments. During the experiment, average weight, transverse and longitudinal diameter, pulp thickness, number of lobules, soluble solids, β-carotene and lycopene concentrations were evaluated. Moreover, the vegetative development of plants was analyzed utilizing vegetation index, obtained using remotely piloted aircraft. The data were analyzed using mean test and multivariate analysis. The results showed that vegetation index can distinguish hybrids from inbred lines and can be used to evaluate tomato germplasm in future phenotyping. crop time Thus of3 evaluated UFU57 UFU 57 UFU-5 hybrid 4 treatments weight diameter thickness lobules solids βcarotene β carotene Moreover aircraft analysis UFU5 5 UFU-

ABSTRACT Among the management and control tactics of the coffee berry borer Hypothenemus hampei (Ferrari), there is the use of entomopathogenic fungi. Due to the importance of prospecting isolates of entomopathogenic fungi for the control of the coffee berry borer, the objective of this study was to evaluate the efficiency of 26 isolates of entomopathogenic fungi in the control of this insect pest in the laboratory. The coffee berry borers were immersed in a solution adjusted to the concentration of 1 to 3 × 108 conidia/mL of each isolate and the control treatment (sterilized water). After seven days total mortality and confirmed mortality were evaluated. The isolates that caused the highest mortality and two commercial isolates were selected for evaluation of lethal concentration (LC50 and LC90) and lethal time (LT50 and LT90). Coffee berry borers were treated at different conidia concentrations for lethal concentration to assess total and confirmed mortality. For a lethal time, the coffee berry borers were treated at the concentration of 108 conidia/mL of the selected isolates, and, after two days and every 24 hours until the eighth day, the number of dead individuals was verified. Among the 26 isolates evaluated, 24 presented mortality higher than the control treatment, and three presented mortality higher than 85%. In the LC50 and LC90 assays, the IBCB 353 and IBCB 364 isolates were more lethal to H. hampei. In the LT50 and LT90 assays, the IBCB 66 and IBCB 353 isolates caused lethality in a shorter time. Ferrari, Ferrari , (Ferrari) 2 laboratory 10 conidiamL mL sterilized water. water . water) evaluated LC (LC5 LT (LT5 LT90. LT90) day verified 85 85% LC5 LC9 assays 35 36 H LT5 LT9 6 (Ferrari (LC (LT 8

Resumo: O objetivo deste trabalho foi avaliar a atividade inseticida de formulação botânica com óleo de nim (Azadirachta indica) e D-limoneno no controle de Hypothenemus hampei, bem como determinar a composição de ácidos graxos do óleo de nim. O óleo de nim 95% foi extraído de sementes de A. indica prensadas a frio, e o D-limoneno, da casca de frutas cítricas. Extrato húmico (carbono orgânico), potássio, cálcio, magnésio e enxofre foram adicionados como aditivos. A análise do óleo de nim por cromatografia gasosa acoplada à espectrometria de massa mostrou que o ácido linoleico (49,28%) é o principal ácido graxo na sua composição. Os testes em campo foram realizados em cafeeiro (Coffea arabica) 'Topázio MG 1190', com quatro aplicações do composto formulado, a cada 20 dias, por um período de 64 dias. Para análise da atividade inseticida, a formulação botânica foi aplicada em papel filtro ou topicamente no dorso do inseto, tendo mostrado mortalidade de 63,34 e 100% após 48 horas, respectivamente. Em campo, a atividade inseticida causou redução de 62,4% na incidência da população de H. hampei, em comparação ao controle. A formulação botânica avaliada é eficiente no controle de H. hampei em cafeeiro.

Abstract: The objective of this work was to evaluate the insecticidal activity of a botanical formulation with neem (Azadirachta indica) oil and D-limonene for the control of Hypothenemus hampei, as well as to determine the fatty acid composition of neem oil. Ninety-five percent neem oil was extracted from cold-pressed A. indica seeds, and D-limonene, from citrus peel. Humic extract (organic carbon), potassium, calcium, magnesium, and sulfur were included as additives. The analysis of neem oil by gas chromatography coupled to mass spectrometry showed that linoleic acid (49.28%) is the main fatty acid in its composition. Field tests were carried out on 'Topázio MG 1190' coffee (Coffea arabica) trees, with four applications of the formulated compound every 20 days for a period of 64 days. For the evaluation of insecticidal activity, the botanical formulation was applied to filter paper or topically on the insect’s dorsal side, showing a mortality of 63.34 and 100% after 48 hours, respectively. In the field, insecticidal activity caused a 62.4% reduction in the incidence of the H. hampei population, when compared with the control. The evaluated botanical formulation is efficient in controlling H. hampei in coffee plants.

ABSTRACT Helicoverpa armigera (Hübner) is a polyphagous insect of difficult control and maize is an important host crop of this insect. Entomopathogenic nematodes (EPNs) are control agents of soil pests. This study aimed to verify the action of EPNs for the control of H. armigera pupae. Laboratory and greenhouse bioassays were conducted to select the concentration of nematode application and subsequently field test were conducted. It was obtained that Heterorhabditis amazonensis MC01 at the concentration of 400 infective juveniles (IJs) ·pupa-1 caused the highest mortality in a lower concentration, whereas for H. amazonensis JPM4, concentrations of both 200 and 400 IJs ·pupa-1 were similar causing pupae mortality. In the greenhouse, H. amazonensis MC01 caused mortality reached values of 80% after 10 days, at concentrations of 600 and 800 IJs ·pupa-1. The highest mortality caused by Steinernema carpocapsae was observed at eight days after the juvenile application, at a concentration of 600 IJs ·pupa-1, also reaching 80% mortality. In the field test, both forms of application were considered appropriate for H. amazonensis MC01, causing mortality rates of up to 80%.

ABSTRACT Coffee production faces challenges due to the susceptibility of the crop to insects. Owing to the coffee leaf miner Leucoptera coffeella, which is one of the main insect pests, the technology for the application of phytosanitary measures becomes the main challenge for coffee growers. This study aimed to evaluate the effectiveness of coffee leaf miner control using different methods of application. The study was conducted in an experimental site in the municipality of Monte Carmelo - Minas Gerais. Spray depositions in different positions of the plant canopy and the effective control of coffee leaf miner were evaluated using the following application treatments: a hydropneumatic sprayer with varying spray volumes (200 and 400 L ha-1), two hollow-cone spray nozzles with the presence and absence of agricultural adjuvant, and electrostatic application using a spray volume of 200 L ha-1 with and without spray adjuvant. The addition of an adjuvant to the spray did not influence coffee leaf miner control; in contrast, a spray volume of 200 L ha-1 combined with the application of coarse droplets was efficient in the management of insect pest. The reduction in the rate of the application using coarse droplets increased the operational capacity and reduced spray drift potential.

RESUMO: Os nematoides entomopatogênicos (NEPs) apresentam potencial para utilização em programas de manejo integrado de pragas. Como pouco se conhece sobre a presença desses organismos no estado de Santa Catarina, objetivou-se realizar amostragens de solo nas cidades de Chapecó, Palmitos, Seara e Concórdia para o isolamento de NEPs. No total foram coletadas 200 amostras (100 g solo). Em Chapecó, foram coletadas 40 amostras em solo contendo adubo verde (Raphanus sativus), cinco amostras de área de floresta nativa e cinco amostras de mata ciliar. Em Palmitos, foram obtidas dez amostras em cada área, totalizando 40. Foram elas: soja (Glycine max), milho (Zea mays), aveia (Avena strigosa) e pastagem (Pennisetum purpureum). Realizaram-se 60 amostras de solo na cidade de Concórdia, em área de pastagem (A. strigosa). Em Seara, as 50 amostras de solo foram retiradas em um local de consórcio de pastagem entre azevém (Lolium multiflorum) e aveia preta (A. strigosa). Para o isolamento, as amostras de solo coletadas foram acondicionadas em recipientes plásticos de 350 mL e alocadas no laboratório da universidade. Foram posteriormente inseridas quatro larvas de Tenebrio molitor de último instar, e mantiveram-se os conjuntos em temperatura de 25°C por sete dias. Após esse período, verificou-se a presença de larvas mortas, e a confirmação da mortalidade por NEP foi feita por meio de armadilha de White. As amostras positivas para NEPs foram obtidas da cidade de Chapecó (População 7, 18, 26) e Concórdia (População Concórdia), o que correspondeu a 2% do total de amostras de solo.

ABSTRACT: Entomopathogenic nematodes (EPNs) are potential candidate for integrated pest management programs. As little is known about the presence of these organisms in the state of Santa Catarina, it was aimed to perform soil sampling in the cities of Chapecó, Palmitos, Seara and Concordia for the isolation of EPNs. In total, 200 samples (100 g soil) were collected. In Chapecó, 40 samples from soil containing green manure (Raphanus sativus), five samples from native forest area and five samples from riparian forest were collected. In the city of Palmitos, 40 soil samples were obtained in the areas of soybean (Glycine max), corn (Zea mays), oats (Avena strigosa), and pasture (Pennisetum purpureum), and in each location 10 samples were taken. Sixty soil samples were collected in the city of Concordia, in a pasture area (A. strigosa). In Seara, the 50 soil samples were collected at a pasture consortium site between ryegrass (Lolium multiflorum) and black oats (A. strigosa). For the isolation, the collected soil samples were conditioned in 350 mL plastic containers and sent to the laboratory of the university. Later, four larvae of Tenebrio molitor of last instar were inserted, and the sets were maintained at the temperature of 25°C for seven days. After this period, the presence of dead larvae was verified, and the confirmation of the mortality by EPNs was evaluated using of White’s trap. The positive samples for EPNs were obtained from the cities of Chapecó and Concordia, which corresponded to 2% of the total soil samples.

ABSTRACT Stenoma catenifer is considered the main pest of avocado, making impossible to commercialize the infested fruits. This study was conducted with the objective of evaluating the potential of Heterorhabditis amazonensis MC01 in the field control of avocado borer, as well as the nematode release method. Two treatments were tested, namely: release of dead Tenebrio molitor infected with the nematode and hydraulic nematode spraying; hydraulic application of chemical insecticides was used as a control. The experiment was set up in a randomized complete block design with 15 replicates. The concentration of suspension distribution was 5,500 infective juveniles per m2. At the experimental area traps with sex pheromone were installed to capture adult males. The number of borer fruits was evaluated in the two central plants of each plot, sampling 4 fruits per plant. There was a reduction in the percentage of borer fruits from 15 days of application for all control methods. After the release of nematodes, the adult population was similar to the control, and it can be inferred that, even without chemical control, there was no increase in the number of adults. Thus, H. amazonensis was considered promising under field conditions, reducing the populations of S. catenifer, in all release methods.

RESUMO: O objetivo deste estudo foi verificar os visitantes florais de canola na região do Triângulo Mineiro, Minas Gerais, Brasil. Utilizou-se um delineamento experimental de blocos inteiramente randomizados com dois híbridos e 10 amostras replicadas, totalizando 20 amostras. A pesquisa de visitantes florais foi feita durante 10 dias. As análises faunísticas das espécies coletadas foram realizadas com base na frequência, constância, domínio, riqueza e diversidade. Um total de 2.676 indivíduos pertencentes a 13 espécies de abelhas de duas famílias (Apidae e Halictidae) foram coletados. A riqueza das espécies encontradas entre os híbridos foi semelhante (10 espécies no híbrido 61 e 12 espécies no híbrido 433), bem como o índice de diversidade (1,28 no híbrido 61 e 1,50 no híbrido 433). A espécie Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae), Paratrigona lineata (Lepeletier, 1836) (Hymenoptera: Apidae) e Trigona spinipes (Fabricius, 1793) (Hymenoptera: Apidae) foram as mais abundantes e constantes nas culturas durante todos os dias avaliados para ambos os híbridos. Com isso, é importante que sejam feitos esforços para conservar as áreas naturais próximas às culturas, a fim de fornecer recursos para a permanência de visitantes florais na área.

ABSTRACT: The objective of this study was to verify floral visitors of canola in the Triângulo Mineiro region, Minas Gerais, Brazil. A completely randomized plot design with two hybrids and 10 replicates was used, totaling 20 plots. The survey of floral visitors was made during 10 days. Faunal analyses of the collected species were performed based on frequency, constancy, dominance, and diversity. A total of 2,676 individuals belonging to 13 species of bees of two families (Apidae and Halictidae) were collected. The diversity index found among hybrids was similar (1.28 in hybrid 61 and 1.50 in hybrid 433). The species Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae), Paratrigona lineata (Lepeletier, 1836) (Hymenoptera: Apidae), and Trigona spinipes (Fabricius, 1793) (Hymenoptera: Apidae) were the most abundant and constant in the crops during all the evaluated days for both hybrids. So, it is important that efforts be made to conserve natural areas close to crops in order to provide resources for the permanence of floral visitors in the area.

Resumen El control biológico es una alternativa al control químico, sin embargo, algunos métodos para su aplicación aún requieren ser mejorados para que atraigan la atención de los usuarios y minimizar costos. En este sentido, este trabajo se llevó a cabo para evaluar el efecto de boquillas de pulverización hidráulica sobre la viabilidad y la infectividad de nematodos entomopatógenos. El experimento tuvo un diseño de bloques completamente al azar, con 37 tratamientos, tres controles y 34 boquillas de pulverización con seis repeticiones. Para las aplicaciones, se utilizó una mesa de pulverización con una presión de 400 kPa. Durante el experimento, se asperjó una suspensión acuosa del nematodo Heterorhabditis amazonensis MC01 a una concentración de 400 juveniles infectivos (JI) ml-1. Se verificó la viabilidad de los JI después de haber sido pulverizado y su infectividad en larvas de Tenebrio molitor. Los resultados indicaron que la viabilidad de nematodos fue influenciada por las boquillas de pulverización hidráulica pero que aquellos viables, no perdieron su capacidad de infectar al insecto.

Abstract Biological control is a viable alternative to chemical control; however, some methods of releasing control agents still need to be improved in order to attract the attention of producers and to reduce costs. Therefore, this work was conducted to evaluate the effects of hydraulic spray nozzles on the viability and infectivity of entomopathogenic nematodes. The experiment was conducted using a completely randomized design with 37 treatments, of which there were three controls and 34 treatments using different spray nozzles with six repetitions. A spraying table was used for the applications. The working pressure was 400 kPa for all nozzles and the solution sprayed consisted of an aqueous suspension of the nematode Heterorhabditis amazonensis MC01 at a concentration of 400 infective juveniles (IJ) mL-1. The viability of the IJ after being sprayed, as well as the infectivity of Tenebrio molitor larvae were verified. The results indicated that nematode viability was influenced by the nozzles and the living nematodes sprayed did not lose their capacity to infect the insect.

Abstract Currently, the main control strategy for arthropod-pests in tomato cropping is the use of synthetic chemical insecticides and miticides. The study aimed to select tomato genotypes of Santa Cruz type, with determinate growth habit, which were rich in acylsugar and presented resistance to spider mite. The evaluated segregating populations were derived from interspecific crossing and were in the advanced generation F2BC2. Genotypes were assessed for acylsugars content, present in leaflets, trichomes at abaxial and adaxial parts and a repellence bioassay to the mite was performed. It was found that the genotype UFU-102-F2BC2#13 stood out in comparison to the others, showing determinate growth habit, high acylsugar content and resistance to spider mite. It was also possible to obtain genotypes that were similar to the wild specie S. pennellii, regarding the acylsugar content.

RESUMO. O objetivo desse estudo foi avaliar a influência da polinização por abelhas na produtividade de canola em diferentes híbridos comerciais, Hyola 61 e Hyola 433, em Minas Gerais. Os estudos foram conduzidos na Fazenda Experimental Água Limpa da Universidade Federal de Uberlândia. Para avaliar os efeitos da polinização de abelhas na produtividade nas sementes de canola, realizou-se um experimento com exclusão dos visitantes florais, comparando a produção em quatro tratamentos: (a) autogamia em Hyola 61 e (b) autogamia em Hyola 433; (c) polinização aberta em Hyola 61 e (d) polinização aberta em Hyola 433 com acesso livre de insetos. As flores disponíveis para polinização apresentaram 25% e 18,8% sílicas mais pesadas e 22,5% e 20,6% mais sementes por sílica em Hyola 61 e Hyola 433, respectivamente, do que aquelas privadas de polinização. Os resultados apontaram que o processo de polinização cruzada, favorecida pela visita de insetos polinizadores, influenciou positivamente alguns parâmetros relacionados a produção, demonstrando-se vantajosa em relação à autogamia da canola no Cerrado Mineiro.

ABSTRACT. The objective of this study was to evaluate the influence of pollinating insects on canola productivity for different commercial hybrids, Hyola 61 and Hyola 433, in Minas Gerais State, Brazil. The studies were conducted at the Fazenda Experimental Água Limpa of the Federal University of Uberlândia. To evaluate the influence of pollination by bees on the production of canola seeds, an experiment was carried out to exclude floral visitors and compare canola seed production following four treatments: (a) autogamy in Hyola 61, (b) autogamy in Hyola 433, (c) open pollination in Hyola 61, with insects having free access, and (d) open pollination in Hyola 433, with insects having free access. Flowers that were available for pollination had 25% and 18.8% heavier pods and 22.5% and 20.6% more seeds per pod in Hyola 61 and Hyola 433, respectively, than those bagged without pollination. The results show that the cross-pollination process, fostered by pollinator visits, positively influenced some parameters related to production, presenting an advantage in relation to canola autogamy in Cerrado Mineiro.

RESUMO: Os nematoides entomopatogênicos (NEPs) são eficazes contra insetos de solo e têm sido usados em sistemas agrícolas. A ação de NEPs sobre grilos (Gryllus L.) (Orthoptera: Gryllidae) foi avaliada em condições de laboratório e campo, a fim de selecionar populações para aplicação em área de cultivo. Foram realizados testes de virulência com Heterorhabditis amazonensis RSC05, H. amazonensis MC01, Steinernema carpocapsae All (Weiser) e H. amazonensis GL, assim como verificadas a adequação da concentração de juvenis infectantes (100, 200, 400 e 600 juvenis infectantes por inseto) e a preferência alimentar sem chance de escolha e com chance de escolha, além do teste de campo utilizando armadilhas para amostragem dos insetos. Verificou-se que todos os isolados causaram mortalidade em Gryllus sp. selecionando-se H. amazonensis MC01 e S. carpocapsae All e que o aumento na concentração de juvenis infectantes resultou em mortalidade crescente dos insetos. Com relação aos testes de preferência alimentar, observou-se que, após 16 horas, não houve alimentação em nenhum dos tratamentos. Nos tratamentos com chance de escolha, constatou-se que houve alimentação dos grilos, independentemente da presença ou não de nematoides. Nos testes de campo, antes da aplicação de juvenis infectantes, foram encontrados 19 grilos vivos nas armadilhas, e após a aplicação dos NEPs em suspensão aquosa foram encontrados 2 grilos vivos. Dessa forma, concluiu-se que H. amazonensis MC01 foi promissor no controle de Gryllus sp. nas condições testadas.

ABSTRACT: Entomopathogenic nematodes are effective in controlling soil insects and they are used in agricultural systems. The virulence of entomopathogenic nematodes on crickets (Gryllus L.) (Orthoptera: Gryllidae) was evaluated under different conditions in order to select populations for application in the field. Virulence tests with Heterorhabditis amazonensis RSC05, H. amazonensis MC01, Steinernema carpocapsae All (Weiser) and H. amazonensis GL were performed. Evaluations were then made of the concentrations of infective juveniles (100, 200, 400 and 600 infective juveniles per insect); feeding preference with or without choice; and field tests using traps to evaluate insect sampling. All isolates were found to cause mortality in Gryllus sp., and H. amazonensis MC01 and S. carpocapsae All were selected; an increase in concentration resulted in increased insect mortality. Regarding the feeding preference tests, after 16 h there was no feeding in any of the treatments. In treatments with a chance of choice, it was verified that the crickets fed, independently of the presence of the nematodes. In the field tests, 19 live crickets were found in the traps, and, after application of entomopathogenic nematodes in aqueous suspension, 2 live crickets were found. Results suggested that H. amazonensis MC01 was promising in the control of Gryllus sp. under the tested conditions.

RESUMO Muitas espécies de nematoides entomopatogênicos apresentam diferenças no modo de busca pelo seu hospedeiro, podendo ser consideradas como "ambusher" ou "cruiser". Essas diferenças podem depender de como esses nematoides detectam os sinais voláteis utilizados como dicas para o forrageamento. Objetivou-se avaliar a resposta locomotora de Heterorhabditis amazonensis RSC5 à liberação de compostos provenientes de exsudatos radiculares de diferentes plantas, ao estímulo produzido pela presença do inseto ou à atividade alimentar do inseto na planta. Foram montadas arenas com substrato ágar-água, contendo exsudatos radiculares de plântulas de milho, feijoeiro, soja, pepino, alho e tomateiro, para verificação de possível escolha por H. amazonensis, bem como em areia contendo, além do exsudato radicular das plântulas, tratamentos com Spodoptera frugiperda, plântula de alho e plântula de alho juntamente com S. frugiperda. A espécie H. amazonensis foi atraída pelas substâncias químicas voláteis emitidas por todos os exsudatos radiculares testados, principalmente aquele obtido da plântula de alho. No entanto, a maior atração ocorreu quando exposta ao tratamento com plântula de alho associada a S. frugiperda, o que evidencia que H. amazonensis se beneficia da associação entre a presença do inseto e os compostos químicos voláteis produzidos pela planta, quando atacada por ele.

ABSTRACT Several species of entomopathogenic nematodes have different host-seeking methods, and could be considered as "ambusher" or "cruiser". These differences may depend on how the nematodes detect the volatile signals used as cues for foraging. This study aimed to evaluate the locomotor response of Heterorhabditis amazonensis RSC5 to the compounds from root exudates of different plants, as well as to stimulants produced by the presence of insects or to the feeding activity of insects on plants. Arenas with agar-water substrates, containing root exudates from corn, bean, soybean, cucumber, garlic and tomato seedlings, were assembled to determine the substrates possibly preferred by H. amazonensis.Arenas with sand were also constructed to include, besides the seedling root exudates, treatments containing Spodoptera frugiperda, garlic seedlings and S. frugiperda feeding on garlic seedlings. The H. amazonensis species was attracted to the volatile chemicals emitted by all the root exudates tested, especially the exudate from garlic seedlings. However, it showed the greatest attraction to the combination of garlic seedlings and S. frugiperda, indicating that the search of H. amazonensis for its host is enhanced by the association between the insect and the volatile chemical compounds produced by plants, when attacked by insects.

Resumen El presente estudio tuvo como objetivo evaluar la liberación de CO2 por juveniles infecciosos (JIs) y la viabilidad de bacterias mutualistas de nematodos entomopatógenos (NEP) expuestos a insecticidas sintéticos. Se probaron dos especies de NEP, Heterorhabditis amazonensis JPM4 y Steinernema carpocapsae All. Los insecticidas aplicados fueron Vertimec® (abamectina) y Klorpan® (clorpirifos). Se empleó cromatografía de gases para el análisis de CO2. Se aislaron las bacterias y se evaluó el desarrollo de colonias en placas de Petri estériles. Vertimec® desencadenó una mayor liberación de CO2 por los nematodos, asociado con cambios en su actividad metabólica, que el Klorpan®. Vertimec® y Klorpan® no inhibieron el desarrollo bacteriano.

Abstract The present study aimed to evaluate the CO2 release by infective juveniles (IJs) and the viability of mutualistic bacteria of entomopathogenic nematodes (EPNs) when exposed to synthetic insecticides. Two species of EPNs, Heteror- habditis amazonensis JPM4 and Steinernema carpocapsae All, were tested. The applied insecticides were Vertimec® (aba- mectin) and Klorpan® (chlorpyrifos). Gas chromatography was employed for CO2 analysis. The bacteria were isolated and the colony development was evaluated in sterile Petri dishes. Vertimec® triggered greater CO2 release by the nematodes, associated with changes in their metabolic activity, than Klorpan®. Vertimec® and Klorpan® did not inhibit the bacterial development.