Resistance of True Citrus species to Diaphorina citri

This is the peer reviewed version of the following article: Eduardo, W. I., Miranda, M. P., Volpe, H. X. L., Garcia, R. B., Girardi, E. A., Alquezar, B., ... & Peña, L. (2022). Resistance of True Citrus species to Diaphorina citri. Pest management science, 78(11), 4783-4792, which has been published in final form at [https://doi.org/10.1002/ps.7098]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] BACKGROUND Host genetic resistance is a promising strategy for the management of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and consequently Huanglongbing (HLB). To date, no study has investigated the resistance to D. citri in the clonal and vegetatively propagated plants of the Microcitrus, Eremocitrus, and Atalantia genera. This study assesses Near and True Citrus genotype antixenosis and antibiosis against D. citri, with trichome density and volatile emission as possible mechanisms of resistance. RESULTS All genotypes were oviposited by D. citri, however, 8 of 14 genotypes were less oviposited than Citrus x sinensis 'Valencia' (susceptible control). Diaphorina citri nymphs had lower nymphal viability in E. glauca (31%) and M. warburgiana (58%) than that in Citrus x sinensis (77%). The behavioral assay showed that 30% of D. citri nymphs in the last instars evaded E. glauca shoots, whereas no nymphs evaded Citrus x sinensis shoots. A higher trichome density was observed in E. glauca shoots compared to the other genotypes. Chemical analysis revealed differences in the volatile profiles of E. glauca and Citrus x sinensis. CONCLUSION Eremocitrus glauca and M. warburgiana genotypes were more resistant to D. citri than Citrus x sinensis. Higher trichome density in the shoots may negatively influence the development of D. citri nymphs. Eremocitrus glauca volatiles may also be involved in their resistance to D. citri.This work was funded by the Fund for Citrus Protection (Fundecitrus), the European Union H2020 Innovation Action Program (grant #817526), and the project PID2019-104569RB-I00 from AEI-Spain. WIE received a postdoctoral fellowship (Proc. 2019/19649-3) from SAo Paulo Research Foundation (FAPESP). MPM received a research fellowship (Proc. 301805/2018-0) from Council for Scientific and Technological Development (CNPq), Brazil. The authors thank the Metabolomic service from Instituto de Biologia Molecular y Celular de Plantas, CSIC/UPV (IBMCP), Valencia, Spain for their help with the volatile emission analysis. The authors also acknowledge Fundecitrus and EMBRAPA Cassava & Fruits for providing plant materials.Eduardo, WI.; Miranda, MP.; Linhares Volpe, HX.; Garcia, RB.; Alquézar-García, B.; Girardi, EA.; Espinosa Ruiz, A.... (2022). Resistance of True Citrus species to Diaphorina citri. Pest Management Science. 78(11):4783-4792. https://doi.org/10.1002/ps.709847834792781

Resistência de cultivares de milho convencional a lagarta do cartucho

A lagarta do cartucho é uma das principais pragas do milho, sendo controladas principalmente por inseticidas químicos, porém está tática de manejo pode ocasionar riscos ao meio ambiente e a saúde humana. A utilização de cultivares resistente pode diminuir a população da praga ocasionando menos danos as lavouras. Sendo assim este trabalho teve como objetivo avaliar a resistência de cultivares de milho a Spodoptera frugiperda. Foram utilizados 11 cultivares de milho em testes de preferência alimentar com e sem chance de escolha, e teste de antibiose. Empregou-se o delineamento experimental inteiramente casualizado para o teste sem chance, e blocos casualizados para o teste com chance de escolha, ambos com seis repetições, e o delineamento inteiramente casualizado com 30 repetições para o teste de antibiose. Nos testes de preferência, avaliou-se a atratividade aos 1, 3, 5, 10, 15, 30, 60, 120, 360, 720 e 1440 minutos e a porcentagem de injúria. No teste de antibiose avaliou-se os aspectos biológicos de 30 lagartas por tratamento. A cultivar AS 1581 apresentou características de resistência na categoria não preferência para alimentação. As cultivares TRUCK e IAC 8390 apresentaram características de resistência na categoria antibiose a S. frugiperda

Alternative to formaldehyde in artificial diet for sugarcane borer and its effects on the parasitoid

The formaldehyde used as anti-contaminant agent in artificial diets of insects can cause serious risks to human health. However, there are products with the same purpose, but with less toxicity to humans. In this sense, the aim of this study was to evaluate the biological parameters of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) fed on an artificial diet containing different anti-infective agents to replace the formaldehyde, as well as analyze the effects on its parasitoid Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae). The experiment was conducted under a completely randomized design, studying the anti-contaminant agents: sodium benzoate, potassium sorbate, 2-phenylphenol, and formaldehyde (standard diet), with deionized water as control. The larvae of sugarcane borer were fed on diets with the cited agents, and were daily observed for: larval and pupal periods, larval and pupal viabilities, number of unviable larvae, longevity, pupae weight, sex ratio and the adults fecundity. To analyze the effects of the anti-contaminant agents on the C. flavipes parasitoid, 50 larvae of sugarcane borer were parasitized and daily observed until the parasitoid pupae formation, being evaluated: number of adults emerged per pupal mass, longevity and sex ratio. D. saccharalis larvae are positively influenced by replacing formaldehyde to 2-phenylphenol in their diet, not causing significant deleterious effects to C. flavipes.The formaldehyde used as anti-contaminant agent in artificial diets of insects can cause serious risks to human health. However, there are products with the same purpose, but with less toxicity to humans. In this sense, the aim of this study was to evaluate the biological parameters of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) fed on an artificial diet containing different anti-infective agents to replace the formaldehyde, as well as analyze the effects on its parasitoid Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae). The experiment was conducted under a completely randomized design, studying the anti-contaminant agents: sodium benzoate, potassium sorbate, 2-phenylphenol, and formaldehyde (standard diet), with deionized water as control. The larvae of sugarcane borer were fed on diets with the cited agents, and were daily observed for: larval and pupal periods, larval and pupal viabilities, number of unviable larvae, longevity, pupae weight, sex ratio and the adults fecundity. To analyze the effects of the anti-contaminant agents on the C. flavipes parasitoid, 50 larvae of sugarcane borer were parasitized and daily observed until the parasitoid pupae formation, being evaluated: number of adults emerged per pupal mass, longevity and sex ratio. D. saccharalis larvae are positively influenced by replacing formaldehyde to 2-phenylphenol in their diet, not causing significant deleterious effects to C. flavipes

Categorias, níveis e causas de resistência de genótipos de feijoeiro a Zabrotes subfasciatus (Boheman, 1833) (Coleoptera: Bruchidae)

The aim of this work was to select bean genotypes with resistance-related traits against Zabrotes subfasciatus (Boheman, 1833) (Coleoptera: Bruchidae) to identify resistance categories, levels and mechanisms. The experiment was carried out at UNESP/FCAV, in the Departamento de Fitossanidade, Laboratório de Resistência de Plantas a Insetos, at 25 ± 1 ºC temperature, 70 ± 10% relative humidity and 12h photophase. Was evaluated antibiosis of bean genotypes to Z. subfasciatus, using completely randomized design with 43 genotypes and 40 seeds (replicates). The seeds were placed in cylindrical plastic containers in which 10 pairs of Z. subfasciatus were released per sample to lay eggs in the seeds. The amount of eggs in each seed was recorded daily in order to obtain two eggs per replicate. Seeds with two eggs were individualized, weighed and kept in 2 mL eppendorf for 10 days to check the eclosion of the larvae daily. At the end of the emergence of the adults the seeds were weighed again and then were dried in an oven to determine the dry weight consumed. Results were subjected to univariate and multivariate analyses to determine the levels of resistance. From this first assay, eight genotypes with resistance-related traits and two susceptible genotypes were screened to validate the prior test and determine the resistance categories and potential mechanisms. For this, free-choice and no-choice tests were performed, both in a completely randomized design with 10 screened genotypes and four replications. In the first test, arenas made of aluminum circular trays were used, which supported circular styrofoam plates with openings on the edges where cylindrical plastic containers with 10 g of seeds of the respective genotypes were inserted equidistantly from the center of the plate. Next, seven pairs of Z. subfasciatus per genotype were released on the center of the plate to evaluate attractiveness ...O objetivo deste trabalho foi selecionar genótipos de feijoeiro com características de resistência a Zabrotes subfasciatus (Boheman, 1833) (Coleoptera: Bruchidae) para identificar as categorias, níveis e causas de resistência. O experimento foi conduzido na UNESP/FCAV no Departamento de Fitossanidade, Laboratório de Resistência de Plantas a Insetos, em sala climatizada à temperatura de 25 ± 1ºC, umidade relativa de 70% ± 10% e fotofase de 12h. Foi avaliada a antibiose de genótipos de feijoeiro a Z. subfasciatus, utilizando delineamento inteiramente casualizado com 43 genótipos e 40 grãos (repetições). Os grãos foram acondicionados em recipientes cilíndricos de plástico sendo liberados 10 casais de Z. subfasciatus por amostras para ovipositarem nos grãos. Diariamente, foi observada a quantidade de ovos em cada grão, a fim de se obter dois ovos por repetição. Os grãos com dois ovos foram individualizados, pesados e colocados em um “eppendorf” de dois mL durante 10 dias para verificação diária da eclosão das larvas. Após 25 dias da oviposição os grãos continuaram a ser observados diariamente, para a quantificação dos adultos emergidos, os quais foram sexados e confinados isoladamente em “eppendorf” de dois mL para avaliação do peso e longevidade. Ao término da emergência dos adultos os grãos foram pesados novamente e depois foram secos em estufa para a determinação da massa seca consumida. Os resultados foram submetidos às análises uni e multivariada para a determinação dos níveis de resistência. A partir desse primeiro ensaio selecionou-se oito genótipos com características de resistência e dois suscetíveis no intuito de validar o teste anterior e determinar as categorias de resistências e possíveis causas. Para tanto foram realizados testes com e sem chance de escolhas, ambos em delineamento inteiramente casualizado com os 10 genótipos ..

Action thresholds for the soybean stink bug complex: phytotechnical and physiological parameters and egg parasitism

Las chinches son consideradas importantes plagas de la soya al causar daños que afectan su producción y comercialización. La determinación de los umbrales de acción para el control de estas plagas garantiza una mayor seguridad en el uso de insecticidas. El objetivo de este estudio fue evaluar el umbral de acción en el manejo de las chinches de la soya y su influencia en los parámetros fitotécnicos y fisiológicos y en el parasitismo de huevos de las chinches. El experimento se instaló en campo, en bloques al azar, utilizando el cultivar Anta 82 RR. Los tratamientos tuvieron cinco umbrales de acción para las chinches fitófagas: 0,5 chinches/m, 1,0 chinche/m, 2,0 chinches/m, 4,0 chinches/m y el control (sin aplicación de insecticidas), con cuatro repeticiones. El muestreo de las chinches se llevó a cabo a través del método del paño vertical y para evaluar el parasitismo se realizaron muestreos semanales de los huevos de las chinches. Los parámetros fisiológicos y fitotécnicos que se evaluaron fueron los siguientes: productividad (kg/ha), peso de 100 semillas, índice de daño a las vainas (%), retención de la hoja, vigor, viabilidad y daño en las semillas. Se observó que los niveles de acción más severos contra chinches influenciaron positivamente en los parámetros fitotécnicos y fisiológicos de la soya, así como el número de semillas por vaina, semillas por planta y vainas por planta. Además el nivel de acción de 1,0 chinche/m es el más indicado para el tratamiento de los chinches de la soya; sin embargo, el parasitismo en este nivel de acción tiende a ser bajo.Stink bugs are major soybean pests, causing damage that affects grain production and marketing. Determining action thresholds for pest control can improve the proper use of insecticides on these pests. This study aimed to evaluate five action thresholds for the management of stink bugs on soybeans, as well as their influence on phytotechnical and physiological parameters as well as on parasitism of stink bug eggs. This study was conducted in the field utilizing a completely randomized block design, using the soybean cultivar ‘Anta 82 RR’. Insecticide application treatments consisted of five action thresholds used against phytophagous stink bugs: half stink bug.m-1, one stink bug.m-1, two stink bugs.m-1, four stink bugs.m-1 and control (no insecticide sprayed), and four replications. Insect sampling was carried out using the beat cloth method, and parasitism evaluations were also taken weekly by conducting stink bug egg samplings. Soybean physiological and phytotechnical parameters, including crop yield (kg.ha-1), 100-seed weight, pod damage index PDI (%), leaf retention, plant vigor, seed viability and damage, number of seeds per pod, seeds per plant, and pods per plant were also assessed. It was observed that the most severe action thresholds used on stink bugs most positively influenced crop phytotechnical and physiological parameters. Moreover, it was noted that one stink bug.m-1 is the optimal action threshold for stink bug management on soybeans, even though egg parasitism at this level tended to be lower

Push-pull and kill strategy for Diaphorina citri control in citrus orchards

The development of sustainable methods to control Diaphorina citri Kuwayama (Hemiptera: Liviidae) is crucial to improve management of huanglongbing (HLB), the most important citrus disease worldwide. In a flushing Citrus × sinensis L. Osbeck (Rutaceae) orchard, this study assessed the combined effects of insecticide-treated Bergera koenigii L. (Rutaceae) trees in the orchard border, as a lethal trap crop, and the application of processed kaolin to the citrus crop, as a repellent (push-pull and kill strategy), in reducing D. citri infestation and dispersal. Additionally, the volatile organic compound (VOC) emission profile and attractiveness of B. koenigii shoots were investigated in indoor experiments. The push-pull and kill strategy reduced the number of D. citri adults on citrus trees by 95, 84, and 63% compared to the untreated control, trap crop only, and kaolin only treatments, respectively. These high reductions can be attributed to the combination of attractive stimuli (VOCs) and repellent stimuli by the trap crop and kaolin, respectively. The number of psyllids observed on citrus trees subjected to treatments with trap crop and kaolin separately was 69 and 86% lower than on untreated control trees, respectively. In addition, all treatments reduced and delayed D. citri dispersal inside the orchard, especially the push-pull and kill strategy. In olfactometric assays, D. citri females showed a significant preference for B. koenigii odors over C. × sinensis cv. ‘Valencia’ flush odors, likely related with the different VOC emission profiles of the two plants. This study shows the effectiveness of push-pull and kill as a new management strategy to control D. citri and consequently HLB.Peer reviewe

Predação e desenvolvimento de Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) alimentado com ácaro rajado Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae) oriundos de feijoeiro

O objetivo do trabalho foi avaliar a capacidade predatória e o desenvolvimento da fase larval de Chrysoperla externa tendo como presa o ácaro rajado advindo de plantas de feijoeiro. O delineamento experimental foi inteiramente casualizado com 2 tratamentos (Tetranychus urticae e Anagasta kuehniella) com 30 repetições (larvas). Para o ensaio da capacidade predatória, as larvas foram individualizadas em placas de Petri, onde foram adicionados discos foliares da planta hospedeira infestados pela praga, contendo 30, 60 e 100 ácaros, respectivamente, para larvas de 1º, 2º e 3º ínstares de crisopídeo. Na avaliação do desenvolvimento do crisopídeo, foram adicionados discos foliares da planta hospedeira infestadas por ácaro rajado, contendo indivíduos sempre superiores à quantidade do consumo do predador. Também foi realizado o ensaio oferecendo ovos de A. kuehniella, como presa padrão. Larvas de 1º, 2º e 3º ínstar de crisopídeo consumiram em 24 horas quantidade inferior de indivíduos de ácaro rajado em relação aos ovos de A. kuehniella. A duração larval de 1º, 2º e 3º ínstar foi de 4,30; 4,33 e 9,69 dias, quando alimentadas com ácaro rajado e 3,11; 3,04 e 3,28 dias quando ofertadas ovos de A. kuehniella. Os menores índices de viabilidade foram obtidos pelas larvas de 2º e 3º ínstar de crisopídeo quando alimentadas com ácaro rajado (53% e 0%, respectivamente). O ácaro rajado alimentado de feijoeiro não é uma presa adequada para o desenvolvimento dos ínstares de C. externa já que inviabiliza o empupamento e influencia na capacidade predatória

Resistance of True Citrus species to Diaphorina citri

Host genetic resistance is a promising strategy for the management of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and consequently Huanglongbing (HLB). To date, no study has investigated the resistance to D. citri in the clonal and vegetatively propagated plants of the Microcitrus, Eremocitrus, and Atalantia genera. This study assesses Near and True Citrus genotype antixenosis and antibiosis against D. citri, with trichome density and volatile emission as possible mechanisms of resistance.Peer reviewe