The role of genetically engineered soybean and Amaranthus weeds on biological and reproductive parameters of Spodoptera cosmioides (Lepidoptera: Noctuidae)

BACKGROUND: In soybean fields containing insecticide- and herbicide-resistant genetically engineered varieties, some weed species have increasingly become difficult to manage and may favor the population growth of secondary pests like Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae). To test this hypothesis, we measured life-history traits, population growth parameters and adult nutrient content of S. cosmioides reared on foliage from four Amaranthus species, from Cry1Ac Bt and non-Bt soybean varieties, and on meridic artificial diet. RESULTS: Larvae reared on A. palmeri and A. spinosus had a shorter development time (5–7 days) than larvae raised on the soybean varieties and A. hybridus. Armyworm survival probability was zero on A. viridis and highest (80% and 71%) on soybeans and A. palmeri. The latter and the artificial diet produced the heaviest larvae and pupae, in contrast to the non-Bt soybean variety. Body nutrient content diverged mostly for adults reared on artificial diet compared with those raised on the soybean varieties. The intrinsic rate of population increase (overall fitness) was 27.88% higher for the armyworms on A. palmeri, Cry1Ac Bt soybean and artificial diet compared with those on non-Bt soybean, A. spinosus and A. hybridus. CONCLUSIONS: Cry1Ac soybean fields infested by some Amaranthus weeds, especially A. palmeri, are conducive to the population growth of S. cosmioides. Integrated pest management programs may be needed to properly manage S. cosmioides in soybean fields, with surveillance for population peaks and judicious control measures when needed.Fil: Páez Jerez, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Hill, Jorge Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Pereira, Eliseu J. G.. Universidade Federal de Viçosa.; BrasilFil: Medina Pereyra, Pilar. Fundación Miguel Lillo; ArgentinaFil: Vera, María Teresa. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

Datos de nivel básico de cuatro insecticidas con diferentes mecanismos de acción para Anastrepha fraterculus y Ceratitis capitata (Diptera: Tephritidae) = Baseline data of four insecticides with different modes of action for Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

La mosca de la fruta del Mediterráneo, Ceratitis capitata (Wiedemann), y la mosca sudamericana de los frutos, Anastrepha fraterculus (Wiedemann) son plagas de gran importancia económica en Argentina y el mundo. Una de las formas de control es el uso de insecticidas en pulverizaciones totales o en cebos. El uso reiterado de un determinado producto ejerce una fuerte presión de selección, pudiendo ocasionar la aparición de resistencia. El objetivo de este trabajo fue determinar el dato de nivel básico de cuatro insecticidas con diferentes mecanismos de acción mediante bioensayos en laboratorio. Los productos utilizados fueron formulaciones comerciales de ciantraniliprol, clorpirifos, lambdacialotrina y spinosad. La concentración letal media se estimó mediante un análisis de la curva dosis-respuesta. Para ciantraniliprol y clorpirifós los machos y las hembras de ambas especies fueron igualmente susceptibles. Para lambdacialotrina se detectaron diferencias entre las dos especies; la CL50 de A. fraterculus (0,058 y 0,074 para machos y hembras respectivamente) fue menor que la de C. capitata (0,523 y 0,624 para machos y hembras respectivamente). Para spinosad, los machos de A. fraterculus fueron igualmente susceptibles que los machos y las hembras de C. capitata. Estos resultados generan valores de referencia para Argentina y evidencian la necesidad de completar este tipo de estudios con evaluaciones de poblaciones naturales sobre las cuales se ejerce control químico así como con ensayos en campo y semi-campo. Asimismo muestran la necesidad de completar este tipo de estudios con evaluaciones de los niveles de ingesta en las distintas concentracionesThe Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the South American fruit fly, Anastrepha fraterculus (Wiedemann) are pests of major economic importance in Argentina and worldwide. One way to control them is the use of insecticide in sprays or baits. The repeated use of a particular product exerts a strong selection pressure and can lead to development of resistance. The aim of this study was to determine baseline data of four insecticides with different mechanisms of action through laboratory bioassays. The products used were commercial formulations of cyantraniliprole, chlorpyrifos, lambdacyalothrin and spinosad. The mean lethal concentration was estimated by a dose-response curve analysis. Cyantraniliprole and chlorpyrifos were equally susceptible for males and females of both species. For lambdacyalothrin differences between the two species were detected; LC50 of A. fraterculus (0.058 and 0.074 for males and females respectively) was lower than that of C. capitata (0.523 and 0.624 for males and females respectively). For spinosad, A. fraterculus males were equally susceptible than males and females of C. capitata. These results generate reference values for Argentina and demonstrate the need to complete these studies with field evaluations of natural populations on which chemical control is exercised as well as with field and semi-field trials. It also shows the need to complete these studies in which the intake at different concentrations is measured.EEA FamailláFil: Juárez, María Laura. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Carrizo, Beatriz Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Musse, Rodrigo Cristián. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Varela, E. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Armiñana, Arturo. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Milla, Fabian Horacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; ArgentinaFil: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: de la Vega, Marcelo Horacio. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentin

Ten years of Cry1Ac Bt soybean use in Argentina: Historical shifts in the community of target and non-target pest insects

Long-term changes in the insect communities in genetically modified (GM) crops expressing target-specific pesticidal proteins can occur and matter for optimized integrated pest management. Using monitoring data of commercial soybean fields from 2012 to 2022, we documented shifts in the abundance of target and non-target insects of the GM Cry1Ac Bacillus thuringiensis (Bt) soybean in two provinces of northwestern Argentina. Before adoption of Bt soybean, lepidopterans prevailed in the crop-associated insect-pest community. They were 65% more abundant than stink bugs and weevils, and the highest population levels (a mean of 169 individuals/plot) were recorded during the vegetative and early reproductive stages. After introducing Bt soybean, the abundance of target lepidopterans (i.e., erebids, heliothines, and plusiines) was the lowest in the 2017–2018 crop season. In the 2020–2021 and 2021–2022 seasons, Rachiplusia nu larvae (Lepidoptera: Noctuidae: Plusiinae) were recorded in Bt soybean fields. The numbers of non-target lepidopterans (Spodoptera spp.) increased year by year, and they were the prevailing lepidopteran species on Bt soybean in 2020–2021 and the R1-R5 (reproductive) soybean growth stages. Weevil abundance was higher on Bt soybean than non-Bt soybean. Stink bugs were more frequent in Tucumán than Catamarca, and their abundances were higher during R1-R5 than during vegetative and late-reproductive stages. The temperature, precipitation, and solar radiation conditioned the abundance of some of the pest complexes. Efforts to monitor and manage secondary or Bt-resistant populations of insect pests are necessary and should be continued and complemented with studies of pest-susceptibility shifts to inform sound locally adapted integrated pest management programs.Fil: Páez Jerez, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Hill, Jorge Guillermo. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pereira, Eliseu J. G.. Universidade Federal de Viçosa; BrasilFil: Alzogaray, Raúl Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Vera, María Teresa. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Determination of developmental parameters of immature stages of Spodoptera cosmioides (Walker) reared on two different substrates

El uso de soja Bt resultó en un avance importante en el control de plagas que afectan este cultivo. Sin embargo, en los últimos años se observó un incremento del daño producido por especies de lepidópteros no blanco de esta tecnología; entre ellas Spodoptera cosmioides (Walker). Este trabajo analizó el desarrollo de estados inmaduros de S. cosmioidescriada en dos sustratos diferentes: Amaranthus spp. y soja Bt. Se utilizaron larvas recién eclosionadas de la F1 obtenida de recolecciones en campos comerciales de soja Bten la provincia de Tucumán, Argentina. Para cada sustrato se partió de 100 larvas que fueron seguidas a lo largo de su desarrollo en forma individual. Diariamente se registró la ocurrencia de mudas y se conservaron las cápsulas cefálicas para su medición. Una vez completado el estado de pupa se pesaron las mismas y se determinó el sexo. Con el número de adultos obtenidos se determinó la viabilidad del estado de pupa. La duración de los estadios larvales, presentó diferencias estadísticamente significativas para los estadios de L2, L6 y L7. En su conjunto, la duración del estado larval fue más lento en soja Bt; que a su vez, presentó estadios adicionales. El ancho de las cápsulas cefálicas mostró diferencias estadísticamente significativas en L2 y L5. Las pupas provenientes de larvas alimentadas con soja Bt fueron más livianas que las de Amaranthus spp. Para la duración del estado de pupa las diferencias fueron estadísticamente no significativas. No se observaron diferencias estadísticamente significativas atribuibles al sustrato para relación de sexos y para el análisis de sobrevida (Kaplan-Meier). Los resultados muestran que la soja Bt resulta un sustrato menos apropiado para el desarrollo de S. cosmioides que Amaranthus spp.ars there has been an increase in damage caused by lepidopteran species not targeted by this technology; among them Spodoptera cosmioides (Walker). This work analyzed the development of immature stages of S. cosmioides reared on two different substrates: Amaranthus spp. and Bt soybean. Newly hatched larvae of the F1 obtained from collections in commercial fields of Bt soybean in the province of Tucumán, Argentina were used. For each substrate, 100 larvae were reared individually throughout their development. The occurrence of molts was recorded daily and the cephalic capsules were kept for measurement. Once the pupal stage was completed, pupae were weighed and the sex was determined. With the number of adults obtained, the viability of the pupal stage was determined. The duration of the larval stadiums presented statistically significant differences for the L2, L6 and L7 stadiums. Overall, the length of the larval stage was slower in Bt soybean; which, in turn, featured additional stadiums. The width of the cephalic capsules showed statistically significant differences in L2 and L5. The pupae from larvae fed Bt soybean were lighter than those of Amaranthus spp. For the duration of the pupal stage the differences were not statistically significant. There were no statistically significant differences attributable to the substrate for the sex ratio and for the survival analysis (Kaplan-Meier). The results show that Bt soybean are a less appropriate substrate for the development of S. cosmioides than Amaranthus sppFil: Zamora Belli, A. L.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Páez Jerez, Paula Gabriela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García Méndez, Diana Daniela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Vera, María Teresa. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: de la Vega, Marcelo Horacio. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; Argentin

Diamide seed treatment may protect early soybean growth stages against Helicoverpa armigera

In intensive soybean cropping systems, early-season pest insects such as lepidopteran larvae can seriously compromise crop establishment. Using a polyphagous global pest ̶̶ the Old World bollworm Helicoverpa armigera (Lepidoptera: Noctuidae), we determined the potential of seed treatments with diamide or neonicotinoid-carbamate mixture for systemic plant protection and residual efficacy against noctuid larvae. In controlled edaphoclimatic conditions, we infested differently aged soybean plants and recorded plant damage and insect mortality, growth, development, and fecundity to assess lethal and sublethal post-exposure effects. The seed treatments reduced plant damage by 50% during 1–7 days after plant emergence. The lowest damage (80% until 14 days after soybean emergence, which was the window of residual control efficacy. Carbofuran or thiodicarb + imidacloprid caused less than 50% larval mortality and minor plant protection against the larvae. There were sublethal effects on the growth, development, and fecundity of the insects surviving on plants of the insecticide seed treatments. The diamide seed treatments reduced the overall insect fitness for a longer time after plant emergence than did the other treatments. Therefore, soybean seed treatment with chlorantraniliprole or cyantraniliprole is potentially efficacious against noctuid larvae in the VE–V1 soybean growth stages (emergence until the first trifoliate), causing lethal and sublethal effects on the insects. Judicious use and effective resistance management for these systemic compounds are relevant as they are helpful for seed treatment and foliar applications against diverse targets.Fil: Páez Jerez, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Alves, Antonio C. L.. Universidade Federal de Vicosa; BrasilFil: Quinteros Cortes, Johana E.. Universidade Federal de Vicosa; BrasilFil: Ribeiro, Leidiana M.. Universidade Federal de Vicosa; BrasilFil: Hill, Jorge Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Gonzatto, Mateus P.. Universidade Federal de Vicosa; BrasilFil: Pitta, Rafael M.. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Pereira, Eliseu J. G.. Universidade Federal de Vicosa; Brasi

Communication interference in sympatrically occurring moth species

In moth species, females emit a species‐specific sex pheromone that is perceived over long distance by conspecific males. The species‐specificity in the chemical communication channel is achieved by a combination of unique components in specific ratios and sometimes also by interspecific behavioural antagonists to deter sympatrically occurring heterospecific males. In this study, we determined possible antagonistic effects in Helicoverpa gelotopoeon Dyar (Lepidoptera: Noctuidae) males to the major sex pheromone component of sympatrically occurring heliothine moths, Z11‐16:Ald, as well as to the sex pheromone of the sympatrically occurring Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) (Z11‐16:Ald and Z9‐14:Ald). We also explored whether other co‐occurring species are attracted to these pheromone blends. Our field experiments showed that the addition of Z11‐16:Ald alone or in combination with Z9‐14:Ald inhibited trap catches of H. gelotopoeon males and that this inhibition depended on the concentration of these compounds. In addition, other moth species were attracted to the blends. Together, our results confirm the antagonistic effect of heterospecific sex pheromone compounds of H. virescens to H. gelotopoeon.EEA Delta del ParanáFil: Juárez, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Ruiz, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Fernández, Patricia Carina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Delta del Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goane, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Villagrán, María Elvira. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Arce, Osvaldo Ernesto Antonio. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Armiñana, A.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Páez Jerez, Paula Gabriela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: de la Vega, Marcelo Horacio. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Groot, A.T.. Max Planck Institute for Chemical Ecology; Alemania. University of Amsterdam. Institute for Biodiversity and Ecosystem Dynamics; Países Bajo

Lemon and Schinus polygama essential oils enhance male mating success of Anastrepha fraterculus

The sterile insect technique (SIT) is an environmentally friendly pest control method that relies on the introduction of sterility into the pest population by the release of sterile males. Many Tephritidae fruit fly pests are currently being controlled with SIT. Sterile insect technique efficacy can be increased if the sexual success of mass-reared sterile males is enhanced. Phytochemicals influence the sexual behaviour of many species of phytophagous insects. Here, we evaluated the possibility of using essential oils to enhance male sexual success of the highly polyphagous fruit fly pest Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), also known as the South American fruit fly. In laboratory tests, we determined the effect of exposing males to volatiles from seven essential oils [Baccharis spartioides (Hook. & Arn) Cabrera (Asteraceae), Schinus polygama (Cav.) Cabrera, Schinus areira (L.) (Anacardiaceae), Zingiber officinale (Roscoe) (Zingiberaceae), Citrus limon (L.) Burm. F., Citrus paradisi Macfad., and Citrus sinensis (L.) Osbeck (Rutaceae)] and two monoterpenes (limonene and citral) that are present at high proportions in some of the oils we evaluated. One exposed and one non-exposed (control) male were placed in a mating arena with one virgin female. We recorded the type of male chosen as mating partner, copula start time, and copula duration. Laboratory males exposed to the volatiles of C. limon and S. polygama essential oils achieved more matings than non-exposed males. The rest of the oils had no effect on male mating success. In addition, limonene-exposed males obtained significantly more matings than non-exposed males, and citral induced a detrimental effect. Exposure to the volatiles of the various essential oils and monoterpenes did not impact on copula start time and copula duration. We discuss the role of essential-oil volatiles on A. fraterculus males’ sexual behaviour and its implications for SITEEA San JuanFil: Ruiz, María Josefina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Jofré Barud, Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Goane, Lucía. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Goane, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Valladares, Gabriela A. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Valladares, Gabriela A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Bachmann, Guillermo E. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Bachmann, Guillermo E. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: Belliard, Silvina A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Belliard, Silvina A. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: Páez Jerez, Paula. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Páez Jerez, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Zamora Belli, Ana Lucía. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: García Méndez, F. Daniela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Segura, Diego F. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Segura, Diego F. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: López, María Liza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: López, María Liza. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentina.Fil: Vera, María T. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Vera, María T. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina