Effiiency of the Essential Oil of Porophyllum linaria (Asteraceae) a Mexican Endemic Plant Against Sitophilus zeamais (Coleoptera: Curculionidae).

The insecticidal and repellent effect of essential oil isolated from fresh leaves of Porophyllum linaria on maize weevil was evaluated, as well as the effect on the grain germination after treated. In total, 28 constituents were identified by gas chromatography coupled with mass spectrometry accounting for 99.86% of whole essential oil. The main majority compounds were ß-myrcene (41.94%), D-limonene (20.29%), and estragole (20.03%). Contact toxicity significantly increased with dose and time after treatment. With the 800 ppm (highest concentration), the mortality (%) obtained for the tenth and fifteenth day was 43 and 82%, respectively, whereas with 50 ppm (lowest concentration) 30% mortality was obtained at the end of the experiment (fifteenth day). At 15 d (end of the experiment), the LC50 y LC90 were obtained with values of 329.01 ± 44.35 y 1058.86 ± 117.76 ppm, respectively. For a concentration of 800 ppm, a selection index of zero was obtained, indicating the preference of the pest to the untreated maize (control). The maize grains germination test showed a significant reduction both in the length of hypocotyl and radicle of maize grain. So, in the highest dose, the hypocotyl and radicle length was 1.40 ± 0.34 and 9.14 ± 0.55 cm, respectively, whereas the control group registered 3.28 ± 0.39 and 13.02 ± 0.97 cm, respectively. This finding is promising since as it could result in the identification of botanical substances capable of suppressing maize weevil, Sitophilus zeamais development.

Spatial Distribution and Flight Patterns of Two Grain Storage Insect Pests, Rhyzopertha dominica (Bostrichidae) and Tribolium castaneum (Tenebrionidae): Implications for Pest Management.

The lesser grain borer, Rhyzopertha dominica, and the rust red flour beetle, Tribolium castaneum, are two major beetle pests commonly found infesting stored products worldwide. Both species can cause severe economic damage and their management is complicated by their potential to develop resistance to several of the limited chemical options available. However, pest management strategies can be improved by understanding the ecology of the pest insect. To determine the spatiotemporal activity of R. dominica and T. castaneum, we conducted a trapping study over two years in a temperate region of south-eastern Australia, with traps located near grain storages and fields. We captured higher numbers of R. dominica than T. castaneum, and both species were more prevalent in traps located close to grain storages. Similar and consistent seasonal patterns were displayed by both species with activity ceasing during the winter (June-August) months. We found linear correlations between maximum daily temperatures and trap catches, and minimum threshold temperatures for flight activity were 14.5 °C and 15.6 °C for R. dominica and T. castaneum, respectively. The results are discussed in relation to the ecology of these pests along with their implications for pest management.

Testing the Insecticidal Activity of Nanostructured Alumina on Sitophilus oryzae (L.) (Coleoptera: Curculionidae) Under Laboratory Conditions Using Galvanized Steel Containers.

Most stored-grain pest insects increase their population within a relatively short time, causing serious damage to stored products. Sitophilus oryzae (L.) is one of the world's major stored-grain pest insects and was chosen as the model insect for our studies. This study compared the efficacy of three different dusts under laboratory conditions: aluminum dust (nanostructured alumina), DiatomiD®, and Protect-It® (commercial diatomaceous earth). Parental survival, grain damage, and progeny production were measured at 250 and 500 ppm in treated wheat. The tests were conducted in 400 mL galvanized steel jars, an experimental model used for the first time to measure the effectiveness of nanostructured alumina, since most studies have been typically performed in small petri dishes. Parental survival obtained was highest in the untreated controls, followed in decreasing order by DiatomiD®, Protect-It®, and nanostructured alumina (NSA). NSA caused the greatest mortality. All treatments significantly reduced grain weight loss and frass production in wheat infested by S. oryzae. The degree of progeny (F1) suppression was directly related to the product and treatment rate, progeny being significantly suppressed by NSA in wheat followed by Protect-It® and DiatomiD®. Therefore, NSA had a greater impact on insect population dynamics.

Phosphine Resistance in North American Field Populations of the Lesser Grain Borer, Rhyzopertha dominica (Coleoptera: Bostrichidae).

Phosphine is the most widely used fumigant for stored grain insect pests, and resistance to phosphine has evolved in several species worldwide. This study was designed to determine the presence of phosphine resistance in 34 populations of Rhyzopertha dominica (F.) collected from the United States and Canada. Adult R. dominica were sampled and subjected to a discriminatory dose toxicity assay of exposure to 20 ppm of phosphine for 20 h of exposure to distinguish a susceptible R. dominica adult by death from a resistant beetle that survives the treatment. All but two of the 34 geographic populations surveyed had some beetles that were resistant to phosphine, and the frequency of resistance varied from 97% in a population from Parlier, California to 0% in beetles from both Carnduff, Saskatchewan and Starbuck, Manitoba. Probit analyses of dose-mortality bioassays with beetles from a laboratory-susceptible strain and those from five of the populations sampled were used to calculate resistance ratio factors (RRs) based on the ratio of LC50 (estimate for the concentration to kill 50% of a test group) in the sampled population to the LC50 for the susceptible strain. The highest RR for the five resistant populations was nearly 596-fold in beetles from Belle Glade, Florida, whereas the lowest RR in that group was 9-fold in Wamego, Kansas. This study revealed that phosphine resistance in R. dominica is common across North America and some populations have levels of resistance that may pose challenges for continued use of phosphine for their management.

Lasioderma serricorne (Coleoptera: Anobiidae): First Report on Black Sesame (Sesamum indicum).

Insect pests may make food products and by-products unfit for human consumption. This study reports the occurrence of Lasioderma serricorne (Coleoptera: Anobiidae) in packaged seeds of black Sesamum indicum. An intact plastic pot of S. indicum seeds was purchased by a consumer in a supermarket in Divinópolis, Minas Gerais state, Brazil, in April 2014 and was kept at his home for 3 months. Two hundred adults of this insect (196 dead and 4 alive) were counted in the pot with the seeds, besides three live larvae. This insect fed on S. indicum seeds, making them unfit for consumption. L. serricorne feed on and reproduce in S. indicum seeds stored in plastic packaging.

Ancient origin and recent range expansion of the maize weevil Sitophilus zeamais, and its genealogical relationship to the rice weevil S. oryzae.

Archeological records attest the early association of Sitophilus with stored cereals from the beginning of agriculture on Asia. The maize weevil (Sitophilus zeamais) became particularly damaging to maize, a cereal crop domesticated on Mesoamerica. We investigated the late evolutionary history of the maize weevil to gain insights on its origin, timing of association with maize, and genealogical relationship to the almost morphologically indistinguishable rice weevil (Sitophilus oryzae). Two mitochondrial genes (cytochrome oxidase subunit I and cytochrome oxidase subunit II) and the nuclear ribosomal gene region were partially sequenced. Analyses showed that the maize weevil shared no haplotypes with the rice weevil; instead, each species exhibited distinct mitogroups and ribogroups. The two weevil species likely split about 8.7 million years ago (95% highest posterior density: 4.0-15.0). Microsatellite data analyses sorted the 309 specimens from 15 populations of the maize weevil into three genotypic groups, which displayed low genetic differentiation and widespread occurrence worldwide. The maize weevil and the rice weevil are each a distinct species; both of which emerged prior to the onset of agriculture. The maize-maize weevil association took place after maize became widespread as a global crop. The maize weevil populations lack spatial genetic structure at the regional, continental, and intercontinental scales.

The damage caused by Callosobruchus maculatus on cowpea grains is dependent on the plant genotype.

BACKGROUND: Beans from cowpea cultivars fertilized with mineral N or inoculated with various rhizobium strains may contain different nitrogen concentrations and nitrogen metabolite composition, which affects the beans' defense mechanisms against pests. In this study, the population growth of Callosobruchus maculatus reared on beans from four cowpea cultivars fertilized with different nitrogen sources was evaluated. The factors tested were beans from four cowpea cultivars and seven different nitrogen sources: mineral N fertilization, inoculation with five strains of symbiotic diazotrophic bacteria, and soil nitrogen (absolute control). RESULTS: BRS Tapaihum and BRS Acauã cultivars had lower cumulative emergence and instantaneous rate of population growth of the insects compared with other cultivars, indicating antixenosis resistance against C. maculatus. Inoculation of BRS Acauã cultivar with the diazotrophic bacteria strain BR 3299 resulted in higher mortality of C. maculatus. For BRS Tapaihum cultivar, inoculation with diazotrophic bacteria strains BR3267, BR 3262 and BR 3299, and nitrogen fertilization resulted in higher mortality among C. maculatus. CONCLUSION: BRS Tapaihum and BRS Acauã cultivars showed the lowest cumulative insect emergence and instantaneous rates of population growth, and the highest insect mortality, mainly when the grains were obtained from plants inoculated with rhizobial strains. © 2016 Society of Chemical Industry.

Antibiose e antixenose de feijão-fava a Zabrotes subfasciatus (Boh) (Coleoptera: Chrysomelidae: Bruchinae) / Antibiosis and antixenosis of lima bean to Zabrotes subfasciatus (Boh) (Coleoptera: Chrysomelidae: Bruchinae)

O feijão-fava é uma importante fonte de proteínas e renda para muitas famílias do Nordeste do Brasil. O gorgulho Zabrotes subfasciatus é uma das principais pragas de feijão-fava armazenado, causando prejuízos quantitativos e qualitativos. A resistência genética é uma das formas mais promissoras para o controle de pragas. Dessa forma, esta pesquisa teve o objetivo de estudar e caracterizar os tipos e os níveis de resistência genética de oito acessos de feijão-fava ao ataque de Z. subfasciatus . Os ensaios foram realizados em laboratório com temperatura e luminosidade controladas, em delineamento inteiramente casualizado, utilizando os acessos UFPI 230, UFPI 264, UFPI 271, UFPI 515, UFPI 468, UFPI 220, UFPI 280 e UFPI 134 como tratamentos. Foram realizados dois testes: sem chance de escolha e com livre chance de escolha. Houve diferenças significativas para número de ovos, insetos emergidos e mortalidade larval/pupal no teste com livre escolha por meio dos testes F e de Scott-Knott a 5% de probabilidade. Os índices de atratividade e de preferência para oviposição revelaram que existem diferentes níveis de resistência do tipo não preferência para oviposição. Todos os acessos apresentaram um nível baixo de antibiose. Os acessos UFPI 220, UFPI 468, UFPI 264, UFPI 134 e UFPI 230 apresentaram resistência por antixenose quando comparados com UFPI 515. O acesso UFPI 515 foi o mais suscetível.(AU)

Lima bean is an important source of protein and income for many families in Northeast Brazil. Zabrotes subfasciatus is the main pest of stored lima bean, which is responsible for quantitative and qualitative losses. Genetic resistance is one of the most promising ways to control pests. Thus, this research aimed to study the genetic resistance of eight accessions of lima bean to Z. subfasciatus attack. Assays were performed in the laboratory with temperature and lighting controlled in a completely randomized design using the UFPI 230, UFPI 264, UFPI 271, UFPI 515, UFPI 468, UFPI 220, UFPI 280, and UFPI 134 accessions as treatments. No-choice and free-choice tests were performed. In the free-choice test significant differences were observed in the number of eggs, emerged insects and larval/pupal mortality using the F test and Scott-Knot, both at 5% of probability. The attractivity and preference indicators for oviposition have shown that there are different resistance levels of no preference type for oviposition. All accessions revealed a low antibiosis level. The UFPI 220, UFPI 468, UFPI264, UFPI 134, and UFPI 230 accessions presented antixenosis resistance when compared to the UFPI 515 accession. The UFPI 515 was the most susceptible.(AU)

Antibiosis and antixenosis of lima bean to Zabrotes subfasciatus (Boh. ) (Coleoptera: Chrysomelidae: Bruchinae) / Antibiose e antixenose de feijão-fava a Zabrotes subfasciatus (Boh. ) (Coleoptera: Chrysomelidae: Bruchinae)

Lima bean is an important source of protein and income for many families in Northeast Brazil. Zabrotes subfasciatus is the main pest of stored lima bean, which is responsible for quantitative and qualitative losses. Genetic resistance is one of the most promising ways to control pests. Thus, this research aimed to study the genetic resistance of eight accessions of lima bean to Z. subfasciatus attack. Assays were performed in the laboratory with temperature and lighting controlled in a completely randomized design using the UFPI 230, UFPI 264, UFPI 271, UFPI 515, UFPI 468, UFPI 220, UFPI 280, and UFPI 134 accessions as treatments. No-choice and free-choice tests were performed. In the free-choice test significant differences were observed in the number of eggs, emerged insects and larval/pupal mortality using the F test and Scott-Knot, both at 5% of probability. The attractivity and preference indicators for oviposition have shown that there are different resistance levels of no preference type for oviposition. All accessions revealed a low antibiosis level. The UFPI 220, UFPI 468, UFPI264, UFPI 134, and UFPI 230 accessions presented antixenosis resistance when compared to the UFPI 515 accession. The UFPI 515 was the most susceptible.(AU)

O feijão-fava é uma importante fonte de proteínas e renda para muitas famílias do Nordeste do Brasil. O gorgulho Zabrotes subfasciatus é uma das principais pragas de feijão-fava armazenado, causando prejuízos quantitativos e qualitativos. A resistência genética é uma das formas mais promissoras para o controle de pragas. Dessa forma, esta pesquisa teve o objetivo de estudar e caracterizar os tipos e os níveis de resistência genética de oito acessos de feijão-fava ao ataque de Z. subfasciatus. Os ensaios foram realizados em laboratório com temperatura e luminosidade controladas, em delineamento inteiramente casualizado, utilizando os acessos UFPI 230, UFPI 264, UFPI 271, UFPI 515, UFPI 468, UFPI 220, UFPI 280 e UFPI 134 como tratamentos. Foram realizados dois testes: sem chance de escolha e com livre chance de escolha. Houve diferenças significativas para número de ovos, insetos emergidos e mortalidade larval/pupal no teste com livre escolha por meio dos testes F e de Scott-Knott a 5% de probabilidade. Os índices de atratividade e de preferência para oviposição revelaram que existem diferentes níveis de resistência do tipo não preferência para oviposição. Todos os acessos apresentaram um nível baixo de antibiose. Os acessos UFPI 220, UFPI 468, UFPI 264, UFPI 134 e UFPI 230 apresentaram resistência por antixenose quando comparados com UFPI 515. O acesso UFPI 515 foi o mais suscetível.(AU)

Antibiosis and antixenosis of lima bean to Zabrotes subfasciatus (Boh. ) (Coleoptera: Chrysomelidae: Bruchinae) / Antibiose e antixenose de feijão-fava a Zabrotes subfasciatus (Boh. ) (Coleoptera: Chrysomelidae: Bruchinae)

Lima bean is an important source of protein and income for many families in Northeast Brazil. Zabrotes subfasciatus is the main pest of stored lima bean, which is responsible for quantitative and qualitative losses. Genetic resistance is one of the most promising ways to control pests. Thus, this research aimed to study the genetic resistance of eight accessions of lima bean to Z. subfasciatus attack. Assays were performed in the laboratory with temperature and lighting controlled in a completely randomized design using the UFPI 230, UFPI 264, UFPI 271, UFPI 515, UFPI 468, UFPI 220, UFPI 280, and UFPI 134 accessions as treatments. No-choice and free-choice tests were performed. In the free-choice test significant differences were observed in the number of eggs, emerged insects and larval/pupal mortality using the F test and Scott-Knot, both at 5% of probability. The attractivity and preference indicators for oviposition have shown that there are different resistance levels of no preference type for oviposition. All accessions revealed a low antibiosis level. The UFPI 220, UFPI 468, UFPI264, UFPI 134, and UFPI 230 accessions presented antixenosis resistance when compared to the UFPI 515 accession. The UFPI 515 was the most susceptible.

O feijão-fava é uma importante fonte de proteínas e renda para muitas famílias do Nordeste do Brasil. O gorgulho Zabrotes subfasciatus é uma das principais pragas de feijão-fava armazenado, causando prejuízos quantitativos e qualitativos. A resistência genética é uma das formas mais promissoras para o controle de pragas. Dessa forma, esta pesquisa teve o objetivo de estudar e caracterizar os tipos e os níveis de resistência genética de oito acessos de feijão-fava ao ataque de Z. subfasciatus. Os ensaios foram realizados em laboratório com temperatura e luminosidade controladas, em delineamento inteiramente casualizado, utilizando os acessos UFPI 230, UFPI 264, UFPI 271, UFPI 515, UFPI 468, UFPI 220, UFPI 280 e UFPI 134 como tratamentos. Foram realizados dois testes: sem chance de escolha e com livre chance de escolha. Houve diferenças significativas para número de ovos, insetos emergidos e mortalidade larval/pupal no teste com livre escolha por meio dos testes F e de Scott-Knott a 5% de probabilidade. Os índices de atratividade e de preferência para oviposição revelaram que existem diferentes níveis de resistência do tipo não preferência para oviposição. Todos os acessos apresentaram um nível baixo de antibiose. Os acessos UFPI 220, UFPI 468, UFPI 264, UFPI 134 e UFPI 230 apresentaram resistência por antixenose quando comparados com UFPI 515. O acesso UFPI 515 foi o mais suscetível.

Bioatividade de três extratos de plantas no controle do Z abrotes subfasciatus (Boh) / Bioactividad de tres extractos de plantas en el control de Zabrotes subfasciatus (Boh) / Bioactivity three plant extracts in control of Zabrotes subfasciatus (Boh.)

Introdução: o conhecimento dos efeitos indesejáveis do uso de inseticidas químicos, associados à preocupação dos consumidores quanto à qualidade dos alimentos, têm exigido estudos sobre novas técnicas de controle das pragas de armazenamento, incluindo-se a utilização de produtos naturais que são menos agressivos ao ambiente, sendo exigido na produção orgânica e na agricultura familiar. Objetivo: avaliar a bioatividade inseticida de extratos vegetais em pó e hidroalcoólicos de Aspidosperma pyrifolium (Mart.), Anadenanthera colubrina (Vell.) e Licania rígida (Benth), a partir de folhas e casca do caule de cada espécie sobre a repelência/atratividade e mortalidade do Zabrotes subfasciatus (Boh.). Métodos: as plantas foram coletadas no sertão paraibano de Patos - PB e, os insetos de uma população pertencente ao Laboratório de Armazenamento e Processamento de Produtos Agrícolas / Universidade Federal de Campina Grande, mantidos em uma massa de feijão em estufa climática sob temperatura controlada. Resultados: constatou-se repelência do Z. subfasciatus a todos os extratos, com destaque para o extrato de L. rigida casca em que o Z. subfasciatus foi repelido em 82,49 por cento, seguidos do A. pyrifolium (78,88 por cento) e A. colubrina (77,49 por cento); o contrário deu-se com o extrato da L. rigida folhas que atraiu os insetos adultos em 40,29 por cento, constatando que os extratos cascas foram superiores aos extratos folhas. Em relação à mortalidade do inseto não se constatou diferença para os extratos das folhas e cascas, no tempo de 24 h, de A. pyrifolium e L. rigida, mas, para o A. colubrina folhas houve efeitos mais eficientes para mortalidade. Conclusão: os extratos foram eficientes no controle do Z. subfasciatus, em que o extrato A. pyrifolium casca se destaca na bioatividade matando em 100 por cento os insetos(AU)

Introducción: el conocimiento de los efectos adversos del uso de insecticidas químicos, asociado a las preocupaciones de los consumidores sobre la calidad de los alimentos, han requerido estudios sobre nuevas técnicas para el control de plagas de almacén, incluye, el uso de productos naturales que son menos dañinos, son exigido en la producción orgánica. Objetivo: evaluar la bioactividad de extractos de plantas con insecticidas hidroalcohólico y polvo de las hojas y la corteza del tallo de las especies Aspidosperma pyrifolium (Mart.), Anadenanthera colubrina (Vell.) y Licania rígido (Benth) en la repelencia/atractivo y mortalidad del Zabrotes subfasciatus (Boh.). Métodos: las plantas fueron recolectadas en tierras del interior de Paraíba (Patos ­ PB) y los insectos de una población pertenecientes al Laboratório de Armazenamento e Processamento de Produtos Agrícolas / Universidade Federal de Campina Grande, mantenidos en una masa de frijoles dentro de una cámara climática a temperatura controlada. Resultados: los adultos de Z. subfasciatus fueron repelidos por todos los extractos, empleados, a donde el extecto de la orteza de L. rígida repelio el Z. subfasciatus en 82,49 por ciento, seguido por A. pyrifolium (78,88 por ciento) y A. colubrina (77,49 por ciento); lo opuesto se dio con el extracto de las hojas de L. rígida que atrajeron a los insectos adultos en 40,29 por ciento, se examino, que los extractos de cáscara fueron superiores a los extractos de las hojas. En cuanto a la mortalidad del insecto no se encuentra diferencia para los extractos de las hojas y la corteza, en el tiempo de 24 h, de A. pyrifolium y L. rigida, pero para A. colubrina hojas, hubo efecto más significativo de mortalidad. Conclusión: los extractos fueron eficientes en el control del Z. subfasciatus, donde el extracto de la corteza de A. pyrifolium se destaca en la bioactividad, matando 100% los insectos(AU)

Introduction: the knowledge of the adverse effects of the use of chemical insecticides, associated to consumer concerns regarding to the quality of food, have required studies on new techniques for control of storage pests, including the use of natural products that are less aggressive to the environment, being required in organic production and family farming. Objective: evaluate the insecticidal bioactivity of powder plant extracts and hydroalcoholic of Aspidosperma pyrifolium (Mart.) , Anadenanthera colubrine (Vell.) and rigid Licania (Benth) from leaves and stem bark of each species on the repellency / attractiveness and mortality of the Zabrotes subfasciatus (Boh.). Methods: the plants were collected in backlands of Paraiba state, Patos - PB and the insects of a population belonging to Laboratório de Armazenamento e Processamento de Produtos Agrícolas / Universidade Federal de Campina Grande, kept in a mass of beans in a chamber under controlled temperature. Results: it was verified repellency of Z. subfasciatus to all extracts, highlighting the extract of rigid L. from bark in which the Z. subfasciatus was repulsed at 82.49 percent, followed by A. pyrifolium (78.88 percent) and A. colubrina (77.49 percent); the opposite happened with the extract of rigid L. from leaves which attracted the adult insects in 40.29 percent, noting that bark extracts were superior to the leaf extracts. In relation to mortality of the insect, is not observed difference for the extracts of the leaves and barks, in the time of 24h, of Apyrifolium and rigid L., but for A. colubrina from leaves there was more efficient effects for mortality. Conclusion: the extracts were efficient in the control of Z. subfasciatus in which the A. pyrifolium extract from bark stands out in the bioactivity killing 100 percent of the insects(AU)

Propiedades insecticidas del polvo de Laurelia sempervirens L. para el control de Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) / Insecticidal properties of Laurelia sempervirens powder to Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) control

Sitophilus zeamais is a key pest of stored cereals. The insecticidal properties of Laurelia sempervirens powder against S. zeamais were assessed in laboratory. The variable evaluated were mortality of adult insects by contact and fumigant toxicity, mortality of immature insects by contact toxicity, residual effect of powder stored under environmental or refrigerated conditions, adult insect emergence (F1), repellency and weight reduction and germination of maize. The concentrations evaluated were 0, 0.25, 0.5, 1.0, 2.0 and 4.0 percent and the experimental design was completely randomly. In contact toxicity bioassay all treatments showed mortality over 90 percent while fumigant activity did not exceed 40 percent. The F1 only was registered in treatment of 0.25 percent and control showing all other treatments 0 percent. In immature control bioassay all treatments exhibited statistical differences with control. The storage of powder under refrigerated conditions not improved the residual effect. All concentrations of powder assessed showed repellence. Germination and grain weight loss of maize seeds not showed significant differences with control. We concluded that L. sempervirens has promissory perspectives to stored grain pests control...

Sitophilus zeamais es plaga primaria de los cereales almacenados. Se evaluaron, en laboratorio, las propiedades insecticidas del polvo de follaje de Laurelia sempervirens para el control de S. zeamais. Las variables evaluadas fueron mortalidad por contacto y fumigante de insectos adultos, toxicidad por contacto sobre estados inmaduros, efecto residual del polvo almacenado en condiciones ambientales y de refrigeración, emergencia de insectos adultos (F1), repelencia y pérdida de peso y germinación del maíz. Las concentraciones evaluadas fueron 0; 0,25; 0,5; 1,0; 2,0 y 4,0 por ciento y el diseño experimental fue completamente al azar. En el bioensayo de toxicidad por contacto todos los tratamientos mostraron una mortalidad sobre el 90 por ciento, mientras que la actividad como fumigante no superó el 40 por ciento. La F1 sólo se registró en el tratamiento de 0,25 por ciento y en el testigo mostrando todos los otros tratamientos 0 por ciento. En el bioensayo de control de estados inmaduros todos los tratamientos exhibieron diferencias significativas con el testigo. El almacenamiento del polvo en condiciones de refrigeración no mejoró el efecto residual. Todas las concentraciones de polvo evaluadas registraron efecto repelente. La germinación y pérdida de peso de las semillas de maíz no mostraron diferencias significativas con el testigo. Se concluye que L. sempervirens tiene perspectivas promisorias para el control de plagas de los granos almacenados...

Does cypermethrin affect enzyme activity, respiration rate and walking behavior of the maize weevil (Sitophilus zeamais)?

Insecticides cause a range of sub-lethal effects on targeted insects, which are frequently detrimental to them. However, targeted insects are able to cope with insecticides within sub-lethal ranges, which vary with their susceptibility. Here we assessed the response of three strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) to sub-lethal exposure to the pyrethoid insecticide cypermethrin. We expected enzyme induction associated with cypermethrin resistance since it would aid the resistant insects in surviving such exposure. Lower respiration rate and lower activity were also expected in insecticide-resistant insects since these traits are also likely to favor survivorship under insecticide exposure. Curiously though, cypermethrin did not affect activity of digestive and energy metabolism enzymes, and even reduced the activity of some enzymes (particularly for cellulase and cysteine-proteinase activity in this case). There was strain variation in response, which may be (partially) related to insecticide resistance in some strains. Sub-lethal exposure to cypermethrin depressed proteolytic and mainly cellulolytic activity in the exposed insects, which is likely to impair their fitness. However, such exposure did not affect respiration rate and walking behavior of the insects (except for the susceptible strain where walking activity was reduced). Walking activity varies with strain and may minimize insecticide exposure, which should be a concern, particularly if associated with (physiological) insecticide resistance.

Actividad insecticida del polvo de Peumus boldus Molina (Monimiaceae) contra Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) / Insecticidal activity of Peumus boldus Molina (Monimiaceae) powder against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

The insecticidal properties of foliage´s powder of Peumus boldus Molina against adults and immature S. zeamais were evaluated. The highest toxicity in contact and fumigant activity was reached by concentrations upper to 1.25 percent showing mortality over to 90 percent. The treatments with high mortality showed a lower adult insect emergence (F1) and grain weight loss too. In immature S. zeamais control lower F1 was observed in highest concentrations of powder. The storage of powder under refrigerated conditions not prevents the insecticidal properties lost. All evaluated concentrations exhibited repellent activity against S. zeamais adults. The powder of P. boldus does not affect the grain germination. We concluded that powder of P. boldus has promissory perspectives to stored products pests control.

Se evaluaron las propiedades insecticidas del polvo de follaje de Peumus boldus Molina para el control de adultos y estados inmaduros de S. zeamais. La mayor toxicidad por contacto y fumigación se obtuvo con las concentraciones iguales o mayores a 1,25 por ciento registrando una mortalidad superior a 90 por ciento. Los tratamientos con mayor mortalidad mostraron también una baja emergencia de insectos adultos (F1) y menor pérdida de peso del grano. En el control de estados inmaduros la menor F1 se observó en las concentraciones más altas de polvo. El almacenamiento del polvo en refrigeración no impidió la pérdida en el tiempo de las propiedades insecticidas. Todas las concentraciones evaluadas mostraron efecto repelente contra adultos de S. zeamais. El polvo de P. boldus no afectó significativamente la germinación de los granos. Se concluye que el polvo de P. boldus tiene perspectivas auspiciosas para el control de plagas de los productos almacenados.

Toxicidade de óleos essenciais de eucalipto e citronela sobre Sitophilus zeamais Motschulsky (Coleoptera: curculionidae) / Toxicity of essential oils of eucalyptus and citronella on Sitophilus zeamais Motschulsky (Coleoptera: curculionidae)

As análises realizadas por cromatografia gasosa acoplada à espectrometria de massas CG/EM apresentou o citronelal como o principal fitoconstituinte dos óleos essenciais de Corymbia citriodora Hill & Johnson, e Cymbopogon nardus (L.), com 61,78 e 36,53%, respectivamente. A toxicidade dos óleos essenciais e do citronelal foi verificada para Sitophilus zeamais por meio das estimativas das curvas de concentrações resposta e tempos de exposição letais para 50 e 95% dos insetos (CL50, CL95, TL50 e TL95). A toxicidade do citronelal foi maior para S. zeamais, com CL50 e CL95 de 0,340 e 0,820µL/cm2 e TL50 e TL95 de 11,89 e 59,50h, respectivamente. A repelência de S. zeamais foi maior para os óleos essenciais de C. nardus e C. citriodora nas concentrações de 0,660; 0,881; 1,101 e 1,321µL/cm2 com 86,6 a 98,8%. O número de insetos emergidos dos grãos pulverizados com os óleos essenciais foi maior para o citronelal nas concentrações de 0,330; 0,440; 0,550, e 0,660µL/cm2 . A redução da massa de grãos foi menor para aqueles grãos tratados com C. citriodora e C. nardus. Óleos essenciais de C. citriodora e C. nardus podem proteger produtos armazenados pelo dano causado por S. zeamais.

Analysis of GC / MS showed citronellal as the main phytochemicals of the essential oils of Corymbia citriodora and Cymbopogon nardus, with 61.78% and 36.53%, respectively. The toxicity of essential oils and citronellal was verified for maize weevils, through the estimates of the concentration response curves and lethal exposure times, for 50% and 95% of the adults insect (LC50, LC95, LT50 and TL95). The toxicity of citronellal was higher for Sitophilus zeamais, with LC50 and LC95 of 0.340 at 0.820 µL/cm2, TL50 and TL95 of 11.89 and 59.50h, respectively. The repellency of S. zeamais was higher for the essential oils of C. nardus and C. citriodora, at concentrations of 1.321, 1.101, 0.881 and 0.660 µL/cm2, ranging from 86.6 to 98.8%. The number of insects emerged from grain sprayed with essential oils was lower for the citronellal, at concentrations of 0.330, 0.440, 0.550, and 0.660 µL/cm2. The reduction in grain weight was lower for those grains, treated with C. citriodora and C. nardus. Essential oils of E. citriodora and C. nardus can protect stored products from damage caused by S. zeamais.

Spread of phosphine resistance among brazilian populations of three species of stored product insects

The resistance to fumigant insecticides in stored-products insects is often recorded. Several factors influence the evolution of insecticide resistance. Among these, the frequency of applications and the migration of resistant populations are of primary importance for the stored-product insects. The aim of this study was to characterize the spectrum and investigate the status of phosphine resistance in Brazil, in 13 populations of the Coleoptera Tribolium castaneum Herbst (Tenebrionidae), ten populations of Rhyzopertha dominica (Fabr.) (Bostrichidae), and eight populations of Oryzaephilus surinamensis (L.) (Silvanidae). The pattern of resistance dispersion in the populations of these species was also verified. The bioassays for the detection of phosphine resistance followed the FAO standard method. To test the influence of migration in the evolution of the phosphine resistance, the difference of mortality in the discriminating concentration and the geographical distance among each pair wise combination of collection sites were correlated. None of the populations exhibited mortality above 90 percent in the discriminating concentration, for the three species. Mortality in the discriminating concentration increased with the geographical distance for R.dominica and O.surinamensis. However, no significant linear response was observed among the variables for T.castaneum populations. These results suggest that the dispersion of insects and the local selection are relevant in the evolution of the phosphine resistance in populations of R.dominica and O.surinamensis. In contrast, grain trade and local selection are probably the factors that determine the evolution of the phosphine resistance in populations of T. castaneum.

Flight activity of Sitophilus oryzae (L) and Sitophilus zeamais Motsch (Coleoptera: Curculionidae) and its relationship with susceptibility to insecticides / Atividade de vôo de Sitophilus oryzae (L) e Sitophilus zeamais Motsch (Coleoptera: Curculionidae) e a sua relação com a susceptibilidade a inseticidas

Insect-pest mobility can influence insect susceptibility to the insecticides used to control them. The objective of this work was to evaluate the flight activity of Sitophilus oryzae (L) and Sitophilus zeamais Motsch populations reared on corn and wheat grains, and its relationship with insecticide susceptibility. Unsexed adult insects with ages between 10 and 20 days were placed on a plastic tray. A 40-watt incandescent light bulb was positioned at a 50 cm height relative to the tray. Flight activity was evaluated during 30 min. In the LC50 estimation bioassays, the insects were exposed to dry residues of the organophosphorus insecticide fenitrothion and of the pyrethroid insecticide esfenvalerate on the internal surface of glass vials. Mortality was evaluated 24h after installation of the experiments. Sitophilus zeamais showed greater flight activity when compared with S.oryzae; likewise, insects reared on corn had greater flight activity than those reared on wheat. Sitophilus oryzae was less susceptible to the insecticides studied than S. zeamais. Adults reared on wheat were more susceptible to the insecticides than those reared on corn. This study demonstrates that the lower flight activity of S. oryzae is related to its greater tolerance to insecticides.

A mobilidade de insetos pragas pode influenciar sua susceptibilidade aos inseticidas usados no seu controle. O objetivo do presente trabalho foi avaliar a atividade de vôo em populações de Sitophilus oryzae (L) e Sitophilus zeamais criadas em grãos de milho e trigo, e a sua relação com a susceptibilidade a inseticidas. Insetos adultos não-sexados, com idades entre 10 e 20 dias, foram colocados sobre bandeja plástica. Uma lâmpada de luz incandescente de 40 watts foi posicionada a 50 cm de altura em relação à bandeja. A atividade de vôo foi avaliada durante 30 min. Nos bioensaios para estimar a CL50 os insetos foram expostos a resíduos secos do organofosforado fenitrotiom e do piretroide esfenvalerato sobre a superfície interna de tubos de vidro. A avaliação da mortalidade foi feita 24h após a instalação dos experimentos. Sitophilus zeamais apresentou maior atividade de vôo quando comparada a S. oryzae; outrossim, os insetos criados no milho apresentaram maior atividade de vôo do que aqueles criados no trigo. Sitophilus oryzae foi menos susceptível aos inseticidas estudados do que S. zeamais. Os adultos procedentes da criação em trigo foram mais susceptíveis aos inseticidas do que aqueles procedentes da criação em milho. O presente trabalho demonstra que a menor atividade de vôo de S. oryzae está relacionada a sua maior tolerância a inseticidas.

First record of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), in Pará nut, Bertholletia excelsa (Lecythidaceae) / Primeiro registro da broca-do-café, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), em castanha-do-Pará, Bertholletia excelsa (Lecythidaceae)

We report the occurrence of Hypothenemus hampei (Ferrari) attacking Pará nuts stored in the southeast of Para state. The coffee berry borer successfully colonized and reproduced using Pará nuts as a food source. Based on this observation, the Pará nuts can be used as an alternative food source in rearing the coffee berry borer. Also, attention should be brought to need of proper storage of these nuts to avoid infestation by this pest.

Este trabalho registra a ocorrência de Hypothenemus hampei (Ferrari) em amêndoas armazenadas da castanha-do-Pará, no Sudeste do Pará. O inseto obteve sucesso na infestação e reprodução na castanha-do-Pará. Com base nessa constatação, o uso da castanha-do-Pará pode ser uma alternativa para a criação da broca-do-café. Além disso, cabe alertar para os cuidados com armazenamento dessas amêndoas para se evitar a infestação pelo inseto.

Fenitrothion and esfenvalerate stability during corn and wheat sample processing

The presence of insecticide residues in cereals represents a risk for the consumer, because these substances are used in large scale to protect stored grains from the attack of pests. The effects of three processing methods for corn and wheat samples on the stability of stored-grain protective insecticides were here evaluated. Fenitrothion and esfenvalerate were applied so as to produce theoretical concentrations of 10 and 0.5 mg kg-1, respectively. Two hours after treatment, the grains were processed and deposition was analyzed by gas chromatography. Grain species did not influence insecticide stability. This stability was only dependent upon the processing method and insecticide type. Grains processed together with dry ice provided the greatest percentage of recovery for both insecticides. Regardless of the processing method, more esfenvalerate than fenitrothion was recovered, thus demonstrating the greater stability of the pyrethroid during this operation.

A presença de resíduos de inseticida em amostras de cereais representa um risco ao consumidor, pois estas substâncias são empregadas em larga escala na preservação de grãos armazenados. Neste sentido, o efeito de três métodos de processamento de amostras de milho e trigo na estabilidade de inseticidas protetores de grãos armazenados foram avaliados. O fenitrotion e o esfenvalerato foram aplicados de modo a produzir concentração teórica de 10 e 0,5 mg kg-1, respectivamente. Duas horas após o tratamento, os grãos foram processados e os depósitos analisados mediante cromatografia gasosa. A espécie de grão não teve influência na estabilidade dos inseticidas, sendo que essa estabilidade apenas dependeu do método de processamento e do inseticida. Os grãos processados junto com gelo seco proporcionaram a maior porcentagem de recuperação de ambos os inseticidas. Independente do método de processamento utilizado, conseguiu-se recuperar mais esfenvalerado do que fenitrotion, demonstrando-se assim, a maior estabilidade do piretróide durante esta operação.

Fenitrothion and esfenvalerate stability during corn and wheat sample processing

The presence of insecticide residues in cereals represents a risk for the consumer, because these substances are used in large scale to protect stored grains from the attack of pests. The effects of three processing methods for corn and wheat samples on the stability of stored-grain protective insecticides were here evaluated. Fenitrothion and esfenvalerate were applied so as to produce theoretical concentrations of 10 and 0.5 mg kg-1, respectively. Two hours after treatment, the grains were processed and deposition was analyzed by gas chromatography. Grain species did not influence insecticide stability. This stability was only dependent upon the processing method and insecticide type. Grains processed together with dry ice provided the greatest percentage of recovery for both insecticides. Regardless of the processing method, more esfenvalerate than fenitrothion was recovered, thus demonstrating the greater stability of the pyrethroid during this operation.

A presença de resíduos de inseticida em amostras de cereais representa um risco ao consumidor, pois estas substâncias são empregadas em larga escala na preservação de grãos armazenados. Neste sentido, o efeito de três métodos de processamento de amostras de milho e trigo na estabilidade de inseticidas protetores de grãos armazenados foram avaliados. O fenitrotion e o esfenvalerato foram aplicados de modo a produzir concentração teórica de 10 e 0,5 mg kg-1, respectivamente. Duas horas após o tratamento, os grãos foram processados e os depósitos analisados mediante cromatografia gasosa. A espécie de grão não teve influência na estabilidade dos inseticidas, sendo que essa estabilidade apenas dependeu do método de processamento e do inseticida. Os grãos processados junto com gelo seco proporcionaram a maior porcentagem de recuperação de ambos os inseticidas. Independente do método de processamento utilizado, conseguiu-se recuperar mais esfenvalerado do que fenitrotion, demonstrando-se assim, a maior estabilidade do piretróide durante esta operação.