Multiple resistance to primary pests of grain sorghum hybrids: Spodoptera frugiperda (Lepidoptera: Noctuidae), Diatraea saccharalis (Lepidoptera: Crambidae), and Diceraeus melacanthus (Hemiptera: Pentatomidae)

ABSTRACT Plant resistance is an important tactic within the precepts of Integrated Pest Management, and the existence of grain sorghum hybrids with multiple insect resistance could benefit crop management and sustainability. This study evaluated the susceptibility of 30 grain-sorghum hybrids to three major pests, namely, fall armyworm (FAW) Spodoptera frugiperda, sugarcane borer (SCB) Diatraea saccharalis, and green-belly stink bug (GBS) Diceraeus melacanthus. The hybrids were cultivated and experiments with each insect species were conducted separately in a greenhouse. For FAW, visual injury assessments were performed on plants 7 and 14 days after infestation (DAI). For SCB, insect presence and injury were assessed 40 DAI. For GBS, the plants were evaluated using a damage rating scale 12, 19, and 26 DAI. Cluster analysis allowed separating the grain sorghum hybrids into groups regarding the levels of resistance to each pest. Hybrid BRS373 stood out as moderately resistant to FAW; AG1090, 80G20, BRAVO, BRS373, AG1615, and IG220 were the most promising for SCB; and for GBS, hybrids 50A40, A9735R, JADE, ENFORCER, BUSTER, 50A10, and IG244 were the most nominated. This information will significantly aid sorghum breeding programs focused on developing commercial hybrids that comprise both insect-resistance and high-yield characteristics. However, further research should evaluate potential chemical and morphological plant traits underlying the lower levels of susceptibility to FAW, SCB, and GBS found in the selected sorghum hybrids.

Morphology of immature stages, biological parameters and life table of Microtechnites bractatus (Hemiptera: Miridae) on different host plants

ABSTRACT The garden fleahopper, Microtechnites bractatus (Say) (Hemiptera: Miridae), is associated with several cultivated plant species and, despite its economic importance, little is known about its development and performance in such hosts. We described here, the morphology of immature stages, and evaluated the biology of M. bractatus in beans, potatoes, white clover, alfalfa, and wheat. The bioassays were carried out in the laboratory under controlled temperature (25±2ºC), humidity (UR70±15%), and photoperiod (12L:12D). The eggs of M. bractatus are elongated and slightly curved, without respiratory projections and light yellow in color, becoming dark at the end of the incubation period. Nymphs present an oval-shaped body, a reddish color that intensifies along with the development and dimorphic wing pads in the fifth instar. In the bioassays, the host plants influenced the biological aspects of M. bractatus, both in the immature and adult stages. Nymph survival was higher in clover and alfalfa, while in wheat, it was lower. Clover-fed insects had the longest longevity. The fecundity parameters and egg viability were favored in insects that fed on clover and alfalfa. The fertility life table showed that feeding M. bractatus with clover provides a higher net reproduction rate (R0) and a higher finite ratio of population increase (ʎ). This study contributes to bioecological and behavioral studies on M. bractatus and provides data for the recognition and characterization of individuals in the immature stage.

Diceraeus melacanthus (Dallas) (Hemiptera: Pentatomidae) development, preference for feeding and oviposition related to different food sources

ABSTRACT The dispersion of Diceraeus melacanthus (Dallas) from soybean (first crop season) to maize (second crop season) is facilitated by the presence of weeds (e.g. Commelina benghalensis) and soybean grains on the ground. Understanding insect development and behavior on different food sources is important to develop pest management strategies. Thus, three independent experiments were conducted to study D. melacanthus nymph development, and adult preference for feeding and oviposition in different food source scenarios in the field. The first two trials studied development and food preference of D. melacanthus related to different food sources (C. benghalensis branches, moistened soybean grain + soybean seedlings, maize seedlings + C. benghalensis branches, moistened soybean grains + maize seedlings, moistened soybean grains + C. benghalensis branches, maize seedlings, as well as a standard diet). The third trial evaluated D. melacanthus oviposition preferences between the aforementioned plants. Overall, moistened soybean grains resulted in better nutritional quality, thus being crucial for D. melacanthus development, triggering faster nymph development as well as better overall adult fitness. The combination of soybean grains and maize seedlings or C. benghalensis branches showed great potential to benefit D. melacanthus, since these complementary food sources improved stink bug fitness, increasing mainly adult longevity, fecundity and egg viability. Therefore, it can be concluded that in order to reduce D. melacanthus outbreaks in second season maize, it is important to reduce soybean harvest loss (reducing, therefore, moistened soybean grain on the ground) and eliminate stink bug associated plants like C. benghalensis.

Triatominae (Hemiptera, Reduviidae) in homes: Report of their occurrence in the municipality of Cruzeiro do Sul, Acre, South Western Amazon

Abstract INTRODUCTION: Triatomines are hematophagous insects that are important to public health since they are the vectors of American Trypanosomiasis. The objective of this study was to describe the occurrence of triatomines in homes in Cruzeiro do Sul, Acre, Brazil. METHODS The specimens were collected by an active search inside homes and also by a passive search by the residents. RESULTS: A total of 55 triatomines were captured comprising of 5 species each of the genera Rhodnius, Eratyrus, and Panstrongylus. No colonies were detected, ruling out the possibility of domiciliation. CONCLUSIONS: Information on regional epidemiological dynamics contributes to the prevention and control of disease.

Temporal variation and spatial distribution of the pest insect Edessa meditabunda in cotton (Gossypium hirsutum) as an alternative host plant

ABSTRACT Cotton is an alternative host for Edessa meditabunda (Hemiptera: Pentatomidae), especially after the soybean harvest in surrounding areas, when large numbers of insects invade cotton fields and damage reproductive structures such as flowers and developing bolls. However, no studies on its occurrence and spatial distribution have been conducted in cotton. Therefore, this study was aimed to assess the temporal variation and spatial distribution of E. meditabunda in the alternative host plant, Gossypium hirsutum. The study was carried out in an area of 1.1 ha planted with cotton that was divided in 64 plots of 169 m2 each, where entire cotton plants were examined weekly and E. meditabunda nymphs and adults were counted. Dispersion rates and theoretical frequency distributions were calculated and analyzed with significance level at 5%. Assessments were carried out from seedling emergence until the appearance of bolls, but E. meditabunda was present only during the reproductive stage of cotton plants. This study detected the dispersal of this stink bug from late-cycle soybean fields to cotton, indicating cotton's potential as an alternative host plant, providing shelter and food. Based on aggregation indices, the spatial distribution of nymphs and adults in cotton was aggregated at the beginning of the infestation, but tended toward randomness as bolls reached maturity. The occurrence of E. meditabunda in cotton was best described by the Poisson distribution with significance level at 5%.

First Occurrence and Population Dynamics of Blissus pulchellus (Hemiptera: Blissidae) in Brazil: a new pest of pastures in Roraima

ABSTRACT Cattle production is one of the main economic activities in the state of Roraima, and insect pest attacks in pastures have a negative effect on this sector in the region. Little is known about the species that cause damage to forage fields in the state. This study presents the first report of the occurrence of the chinch bug Blissus pulchellus Montandon (Hemiptera: Blissidae) in Roraima, Brazil and a description of the population dynamics of this pest in pasture areas in this state. Pasture areas were sampled in nine municipalities of Roraima to detect the insect. The population dynamics study was conducted for two years in Alto Alegre municipality, two of which have Brachiaria brizantha cv. Marandu and one of Megathrysus maximus cv. Mombaça (Poaceae) crops. Blissus pulchellus was found in all sampled areas, except in Rorainópolis and São João da Baliza. High densities of this bug were found in in Alto Alegre. This is the first report of B. pulchellus in Brazil. The factors that affect the population dynamics and the damage caused by this insect pest to pastures as well as the risk of dispersal of this pest in Brazil are discussed.

Selection of Interpolators to Predict Populations of Tibraca limbativentris in Irrigated Rice

Abstract Kriging is a method that estimates values in places not sampled from different interpolators, therefore, widely used to predict the spatial distribution of organisms. However, the different interpolators may vary in performance depending on the organism under study or the area evaluated. The aimed study to compare the ordinary kriging and inverse of distance weighted interpolation methods, applied to the spatial distribution of population density of Tibraca limbativentris in irrigated rice. This study was carried out in Santa Maria, RS, Brazil, in two fields with areas of 1.3 ha and 6.2 ha, respectively. Seven evaluations of the population density of T. limbativentris were carried out, corresponding to the period from sowing to maturation. In these areas the adults of T. limbativentris were quantified and the sum used for the statistical and geostatistical analysis. The sample population of T. limbativentris was submitted to different semivariograms, which were selected through cross-validation. The sample population of T. limbativentris was submitted to different semivariograms, selected by means of cross-validation. Once selected, semivariograms were used in both tested interpolation methods. From the results it was concluded that the ordinary kriging interpolation method performed better in all evaluations performed in both areas. Therefore, we recommend its use for estimating the population density and spatial distribution of T. limbativentris in the irrigated rice throughout the crop phenology. Using appropriate interpolation methods, localized management can be used, reducing costs for controlling this pest and increasing the sustainability of the environment.

New pandemic, old bugs: A case of cimicosis (Bed Bug) in a neglected elderly patient during the coronavirus disease quarantine

Abstract Bed bugs are hematophagous arthropods that can parasitize humans. During the coronavirus disease pandemic, there has been an increase in elderly neglect. A man in his 90s came to the hospital complaining of generalized pruritus. Despite being a dependent patient, he was left alone in a home by his relatives during the pandemic. Examination revealed inflammatory nodules in addition to a live bed bug crawling over his trunk. Identifying a bed bug during consultation is an uncommon feature that can help determine a particular diagnosis. As this case shows, the need for social isolation during pandemics can contribute to elder abuse and neglect.

Trissolcus teretis (Johnson, 1987) (Hymenoptera: Scelionidae) parasitism on Euschistus heros (Fabricius, 1798) and Diceraeus melacanthus Dallas, 1851 (Hemiptera: Pentatomidae) eggs at different temperatures

ABSTRACT Trissolcus teretis has been recorded to parasitize eggs not only of Euschistus heros and Diceraeus melacanthus but also of other stink bug species in the most important soybean producing countries of South America such as Brazil, Argentina as well as other countries of the Neotropical region. Despite several studies relating to its natural incidence and parasitism, the impact of different temperatures on biology and parasitism capacity of T. teretis on eggs of E. heros and D. melacanthus is practically unknown. Considering that biological traits can be highly influenced by temperature, research on T. teretis parasitism at different temperatures and hosts is of theoretical and practical interest. We therefore evaluated T. teretis parasitism and development on eggs of E. heros and D. melacanthus at 15ºC, 20ºC, 25ºC, and 30ºC. Temperature had an impact on the parasitoid reared on eggs of both studied hosts. Although we recorded parasitism at an extreme temperature of 15ºC, these conditions are unfavorable for T. teretis parasitism, impairing parasitoid biological traits, especially survival of larvae and adult parasitism. Therefore, for application in crop fields where temperatures of 15ºC or lower are common, additional studies are necessary to investigate the possible need to increase parasitoid numbers during releases or to choose smaller intervals between multiple releases.

Resistance of cassava genotypes to Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae)

ABSTRACT Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae) is an important cassava pest due to the great potential damage and the increasing population in recent years. However, few studies about bioecology and control of the cassava lace bug have been conducted and their results don't provide adequate control strategies. An alternative to maintain the population below economic injury levels is through the adoption of host plant resistance. To improve the understanding about the bioecology and find new sources of resistance in cassava, the biological parameters and demographics of V. manihotae on five cassava genotypes (Santa Helena, MEcu 72, Col 22, Clone 02 and Clone 03) under controlled conditions (25±2°C, 14L/10D) were evaluated. Duration and viability of the stages, the period egg-adult, sex ratio, the pre-oviposition period, fecundity and longevity of male and female was determined, and a fertility life table was prepared. Insects fed on MEcu 72 showed increased nymphal, egg-adult, and pre-oviposition periods and reduced female fecundity and longevity in comparison to the other genotypes. Demographic parameters (Ro, rm, T, DT) showed a significant impact on the growth potential of V. manihotae fed on MEcu 72 indicating that the populations would diminish over time. The combined effect of these parameters indicated that MEcu 72 has resistance on V. manihotae specimens hindering their development.

New record of Microtechnites bractatus (Say) (Hemiptera: Miridae) infesting Crotalaria spp. and injuries of Miridae in cultivated plants in the State of Paraná, Brazil

Abstract This study reports for the first time the plant bug Microtechnites bractatus (Say) in Crotalaria juncea and Crotalaria spectabilis, in the state of Paraná, Brazil. We characterized the injuries caused by M. bractatus and Collaria scenica Stal in cultivated plants and in Crotalaria spp. Considering that M. bractatus damage has been incorrectly attributed to C. scenica, we present here a contribution to the correct characterization of these insect pests and their damage over some agricultural crops.

First record of Thaumastocoris peregrinus (Hemiptera, Thaumastocoridae) in Pará state, Brazil

Thaumastocoris peregrinus (Hemiptera, Thaumastocoridae) is a phytophagous pest of eucalyptus plantations. It was introduced in Brazil in 2008, and expanded rapidly due to its adaptive capacity to different climatic conditions. Eucalyptus has been planted in the Brazilian Amazon since the 1980s, being used in silvopastoral systems and for cellulose production. Since its introduction in the southernmost Brazilian state of Rio Grande do Sul, T. peregrinus has expanded its geographical distribution to 117 municipalities in states in the south (Rio Grande do Sul, Santa Catarina and Paraná), southeast (São Paulo, Espirito Santo, Rio de Janeiro and Minas Gerais), mid-west (Mato Grosso do Sul and Goiás) and northeast (Sergipe) of the country. Here we report the first record of T. peregrinus in the Brazilian Amazonian state of Pará. (AU)

Mapping of spatiotemporal distribution of Tibraca limbativentris Stal (Hem.: Pentatomidae) in flooded rice crop in Southern Brazil

ABSTRACT The rice stem bug, Tibraca limbativentris Stal (Hem.: Pentatomidae), is one of the main insect pests in Brazilian rice crops. Knowledge of its spatiotemporal distribution can support the development of an effective sampling system and improve IPM strategies. This study aimed to map the spatiotemporal distribution of rice stem bug in flooded rice crop in Southern Brazil. Flooded rice crop was scouted for two seasons to estimate insect densities. Four occurrence categories were observed: no insect, only adults, only nymphs, and both phases. The relationship between phenological stages and insect categories was established. Interpolation (mapping) of occurrence categories of T. limbativentris was performed by multiquadric equations. In two seasons during the rice cycle, the results indicate that rice stem bug "adults" were the most abundant category until the mid-vegetative phase of the rice; "nymphs" were the most abundant from the end of vegetative phase; "adults + nymphs" occurred from the beginning of reproductive phase; there were no rice stem bugs in more than 66% of the area, as they were most concentrated near the edge of the crop. The information presented here provides further knowledge about T. limbativentris spatiotemporal dynamics that can be applied to improve IPM strategies, such as developing sampling plans and localized control measures at the edge of rice fields.

Chemical and morpho-functional aspects of the interaction between a Neotropical resin bug and a sticky plant

Rubus adenotrichos is an Andean blackberry plant bearing glandular trichomes which secrete an adhesive exudate. The resin bug Heniartes stali is frequently found on this plant and collects this exudate using the forelegs to enhance its preying capacity. Here, we describe the morphology of the plant's glandular trichomes with the aid of light and scanning electron microscopy, as well as the chemical components of the exudate by histochemical and gas chromatography-mass spectrometry analysis. We have also combined behavioral observations with the analysis of the insect leg morphology to identify possible morpho-functional adaptations evolved by H. stali for collecting the sticky secretions. Glandular trichomes exhibited a multicellular long stalk and a calyx-shaped head with radially aligned cells. The composition of the resinous fluid was mainly terpenes and phenolics, which may contribute to its sticky properties. Brush-like structures on the tibia of forelegs in H. stali suggests an adaptive trait for collecting the trichomes exudate. A profusely hair-covered area on metatibiae operated as a resin storage structure. Abundant pore-like openings were observed in the cuticle of this area through which substances could be conceivably secreted to prevent resin hardening. These findings combine morphological and chemical features of a fascinating insect-plant interaction in the Neotropics.

Rubus adenotrichos es una planta de mora andina que contiene tricomas glandulares los cuales secretan un exudado pegajoso. El chinche de las resinas Heniartes stali se encuentra con frecuencia en esta planta recogiendo el exudado con sus patas delanteras para mejorar su capacidad en la captura de las presas. En este trabajo empleamos microscopía de luz y microscopía electrónica de barrido para describir la morfología de los tricomas. Los constituyentes químicos del exudado fueron estudiados mediante técnicas histoquímicas, de cromatografía de gases y espectrometría de masas. También combinamos observaciones del comportamiento del insecto en la recolección y almacenamiento del exudado con el análisis de la morfología de sus patas, empleando microscopía de luz y microscopía electrónica de barrido para identificar las posibles adaptaciones morfo-funcionales desarrolladas para la manipulación de estas secreciones adhesivas. Los tricomas glandulares exhibieron un tallo largo multicelular y una cabeza glandular en forma de cáliz con células alineadas radialmente. El fluido resinoso estaba compuesto principalmente por terpenos y compuestos fenólicos, los cuales parecen contribuir con sus propiedades adhesivas. La presencia de estructuras tipo pincel en las puntas de las tibias de las patas delanteras sugieren un carácter adaptativo para recoger el exudado de los tricomas. También describimos un área en las patas traseras profusamente cubierta de pelos, que funcionaban como estructuras de almacenamiento de la resina. En la cutícula de éstas observamos abundantes aberturas similares a poros y sugerimos que a través de ellos se secretan sustancias que impiden el endurecimiento de la resina almacenada. Estos hallazgos aportan información sobre características morfológicas y químicas de un novedoso modelo de interacción insecto-planta en el neotrópico.

Biology of Corythucha gossypii Fabricius, 1794 (Hemiptera: Tingidae) in Ricinus communis at different temperatures and thermal requirements / Biologia de Corythucha gossypii Fabricius, 1794 (Hemiptera: Tingidae) em Ricinus communis em diferentes temperaturas e exigências térmicas

Abstract We studied the biology of Corythucha gossypii in Ricinus communis under different temperatures in climatic chambers adjusted at 20, 23, 25, and 28 °C, 60 ± 10% relative humidity, and a 12-h photoperiod. The development period and viability of eggs, the development period and survival rate of nymphs, and egg-adult cycle of C. gossypii as well as the adult longevity and fecundity were estimated. The thermal requirements (K) and temperature-base (Tb) were estimated for each of the immature stages and for the eggs-adults period. The duration of the eggs and nymphs phases and the egg-adult cycle of the C. gossypii on castor bean leaves at 20-28 °C were 7.6-17 days, 10.2-27.5 days, and 16.9-44.5 days, respectively. The lower temperature inhibited the oviposition of C. gossypii, whereas the higher temperatures were most favorable for its development. The municipalities of the Bahia state of Brumado, Irecê, Itaberaba, Jacobina, and Senhor do Bonfim were estimated to have a high potential for the population growth of C. gossypii. However, a greater number of generations per year of C. gossypii were observed in the municipalities of Brumado and Itaberaba.

Resumo Estudamos a biologia de Corythucha gossypii em Ricinus communis sob diferentes temperaturas em câmaras climatizadas ajustadas as temperaturas de 20, 23, 25 e 28 °C, umidade relativa de 60 ± 10% e fotoperíodo de 12 horas. O período de desenvolvimento e a viabilidade dos ovos, o período de desenvolvimento e a taxa de sobrevivência de ninfas e do ciclo de ovo-adulto de C. gossypii, bem como a longevidade dos adultos e fecundidade foram estimados. As exigências térmicas (K) e as temperaturas-bases (Tb) foram estimadas para cada um dos estádios imaturos e para o ciclo de ovo-adulto. A duração das fases de ovos e ninfas e do ciclo de ovo a adulto de C. gossypii em folhas de mamona a 20-28 °C foram de 7,6-17 dias, 10,2-27,5 dias e 16,9-44,5 dias, respectivamente. A temperatura mais baixa inibiu a oviposição de C. gossypii , enquanto as temperaturas mais altas foram favoráveis ao seu desenvolvimento. Os municípios do estado da Bahia de Brumado, Irecê, Itaberaba, Jacobina e Senhor do Bonfim foram estimados para ter um alto potencial para o crescimento populacional de C. gossypii. No entanto, o maior número de gerações por ano de C. gossypii foi observado nos municípios de Brumado e Itaberaba.

Schinus molle: anatomy of leaves and stems, chemical composition and insecticidal activities of volatile oil against bed bug (Cimex lectularius)

Abstract The present work investigates the leaf and stem anatomy, chemical composition and insecticidal activities (against Cimex lectularius Linnaeus, 1758) of the volatile oils of Schinus molle L., Anacardiaceae, a Brazilian native traditional medicinal plant. Noteworthy micro-morphological features that can help in the identification and quality control of the species include the presence of isobilateral and amphistomatic leaves, anomocytic and cyclocytic stomata, capitate glandular and conical non-glandular trichomes, large secretory ducts in the midrib, presence of druses and prismatic crystals, and the petiole vascular system comprising of five vascular bundles arranged in U-shape and an additional dorsal bundle. The major components of the volatile oil include β-pinene (14.7%), α-pinene (14.1%), limonene (9.4%) and muurolol (11.8%). Insecticidal activities of the volatile oil against bed bugs were investigated for the first time; strong toxicity by fumigation with the volatile oil of S. molle was observed and reported herein.

Rapid detection of human blood in triatomines (kissing bugs) utilizing a lateral flow immunochromatographic assay - A pilot study

BACKGROUND DNA- and proteomics-based techniques are currently used to identify a triatomine human blood meal. These methods are time consuming, require access to laboratories with sophisticated equipment, and trained personnel. OBJECTIVES We tested a rapid and specific immunochromatographic assay (that detects human blood in forensic samples) to determine if human blood was present in triatomines and their fecal excreta. METHODS We fed Triatoma rubida human blood (positive control) or mouse blood (negative control) and performed the assay on the abdominal contents and fecal excreta. Triatomine field specimens collected in and around human habitations and excreta were also tested. FINDINGS The assay was positive in triatomines fed human blood (N = 5/5) and fecal excreta from bugs known to have ingested human blood (N = 5/5). Bugs feeding on mice (N = 15/15) and their fecal excreta (N = 8/8) were negative for human blood. Human blood was detected in 47% (N = 23/49) triatomines, representing six different species, collected in the field. MAIN CONCLUSIONS The pilot study shows that this rapid and specific test may have applications in triatomine research. Further study is needed to determine the sensitivity of this assay compared to other well-established techniques, such as DNA- and proteomics-based methodologies and the assay's application in the field.

Rollinia mucosa (Jacq) Baillon (Annonaceae) active metabolites as alternative biocontrol agents against the lace bug Corythucha gossypii (Fabricius): an insect pest / Metabolitos activos de la semilla de Rollinia mucosa (Jacq) Baillon (Annonaceae) como agentes alternativos de biocontrol sobre el insecto fitopatógeno Corythucha gossypii (Fabricius) / Metabólitos ativos de Rollinia mucosa (Jacq) Baillon (Annonaceae) como agentes de biocontrole alternativos contra Corythucha gossypii (Fabricius): um inseto-praga

Abstract The lace bug, Corythucha gossypii (Fabricius) is a serious pest affecting over 24 wild and commercially important plant species of the families Annonaceae, Passiflorcae, Caricaceae, Euphorbiaceae, and Solanaceae. Thus far, commercial insecticides, such as 0.1% Dimethoate and 0.1% Imidacloprid have shown effectiveness against this insect, but no botanical pesticides are available to control this bug. In the present study, a Rollinia mucosa (Jacq.) Baillon ethanol extract was evaluated as a biological control agent against the lace bug. Through a toxicity assay involving Artemia salina, the median lethal concentration (LC50) of a raw ethanol extract of R. mucosa seeds was determined, as well as that of its Acetogenin (F1) and Alkaloid (F2) fractions; these LC50 were 0.184, 0.082, and 0.0493 μg/mL, respectively. In addition, with an insecticide assay on lace bug nymphs, a mortality percentage of 86.67% at 5 μg/mL after 72h was observed. These data demonstrate that the R. mucosa seed extract is highly active. Further chemical characterization studies revealed that the main active metabolites contributing to extract activity were acetogenins and alkaloids.

Resumen El hemíptero, Corythucha gossypii (Fabricius) es un insecto que causa daño sustancial en cultivos de más de 24 especies de plantas de las familias Annonaceae, Passifloraceae, Caricaceae, Euphorbiaceae y Solanaceae. En su mayoría estas plantas son de interés económico. Aunque insecticidas comerciales como el Dimetoato (0.1%) y el Imidacloprid (0.1%) permiten un manejo eficiente de este insecto-plaga, no se han reportado alternativas botánicas para estos insecticidas sintéticos. En el presente estudio se evaluó el extracto etanólico de la semilla de Rollinia mucosa (Jacq.) Baillon, como un biocontrolador de C. gossypii. A través de un test de toxicidad con Artemia salina se determinó que la concentración del extracto etanólico letal para el 50% de la población bajo estudio (LC50) fue de 0.184 μg/mL. De igual modo se identificó que las fracciones de acetogeninas (F1) y de alcaloides (F2) de este extracto tienen un LC50 de 0.082 y 0.0493 μg/mL, respectivamente. En el ensayo insecticida con ninfas de C. gossypii se observó una mortalidad del 86.67% después de 72 horas de exposición al extracto etanólico a una concentración de 5 μg/mL. Lo anterior demuestra que el extracto es altamente activo. La caracterización química del extracto evidenció que los principales metabolitos activos que contribuyen a su actividad insecticida son las acetogeninas y los alcaloides.

Resumo Corythucha gossypii (Fabricius) é uma praga séria que afeta mais de 24 plantas silvestre e de interesse comercial, pertencentes as famílias Annonaceae, Passifloraceae, Caricaceae, Euphorbiaceae e Solanaceae. Até o momento, inseticidas comerciais como Dimetoato (0.1%) e Imidacloprid (0.1%) apresentam um controle eficiente sobre este inseto, entretanto não há reportes de pesticidas de origem vegetal para o seu controle. No presente estudo, o extrato etanólico de Rollinia mucosa (Jacq.) Baillon foi avaliado como um controle biológico contra Corythucha gossypii. Por meio do ensaio de toxicidade com Artemia salina a concentração letal média (LC50) para o extrato etanólico das sementes, suas frações de acetogeninas (F1) e fração de alcaloides (F2) foi de 0.184, 0.082 y 0.0493 μg/mL, respetivamente. Adicionalmente, na avaliação do ensaio inseticida, se obteve uma porcentagem de mortalidade de 86.67% à concentração de 5 μg/mL após de 72 horas de exposição, demonstrando uma alta atividade do extrato de sementes de R. mucosa. Os estudos em relação à caracterização química evidenciaram que os principais metabólitos que aportam à atividade do extrato foram as acetogeninas e alcaloides.

NEW PLANT ASSOCIATIONS FOR Monalonion velezangeli (HEMIPTERA: MIRIDAE) IN GREEN URBAN AREAS OF BOGOTÁ (COLOMBIA) / Nuevas asociaciones de plantas para Monalonion velezangeli (Hemiptera: Miridae) en áreas verdes urbanas de Bogotá (Colombia)

ABSTRACT Monalonion velezangeli Carvalho and Costa (Hemiptera: Miridae) is a polyphagous plant bug recognized as one of the most important pest species of coffee and avocado in rural regions of Colombia. M. velezangeli is reported for the first time in green urban areas in the high Andean city of Bogotá (Colombia). Specimens were collected on eight species of urban trees planted in the city, of which five represent new plant associations for M. velezangeli. The plant species Schinus molle L. (Anacardiaceae) is for the first time reported as new host plant damaged by M. velezangeli under urban conditions.

RESUMEN Monalonion velezangeli Carvalho and Costa (Hemiptera: Miridae) es un mírido polífago reconocido como una de las especies plaga más importantes del café y el aguacate en regiones rurales de Colombia. M. velezangeli es reportado por primera vez en áreas verdes urbanas en la cordillera de los Andes en la ciudad de Bogotá (Colombia). Los especímenes fueron recolectados en ocho especies de árboles plantados en la ciudad, de los cuales cinco representan nuevas asociaciones de M. velezangeli. La especie Schinus molle L. (Anacardiaceae) es por primera vez reportada como nueva planta hospedera afectada por M. velezangeli bajo las condiciones urbanas.

Quantitative and qualitative damage caused by Oebalus poecilus (Hemiptera, Pentatomidae) to upland rice cultivated in new agricultural frontier of the Amazon rainforest (Brazil) / Danos quantitativos e qualitativos causados por Oebalus poecilus (Hemiptera, Pentatomidae) em arroz de terras altas cultivado na nova fronteira agrícola da Floresta Amazônica (Brasil)

ABSTRACT Oebalus poecilus (Dallas 1851) is one of the stink bug species of great economic importance for rice producers in Brazil of irrigated, flood and upland cropping systems. These pentatomids are known as stink bugs of panicles, because both nymphs and adults feed mainly on panicles. Stink bug attacks result in pecky (spots) seeds, lower mass, germinative reduction and deformed grains. Bearing these factors in mind, the aim of this study was to evaluate the quantitative and qualitative losses in commercial cultivars of upland rice (Cambará variety), submitted to different population levels of stink bugs of panicles, O. poecilus, at different reproductive growth stages. The results show that in upland rice (Cambará variety), the rice grains are susceptible to quantitative (number and weight) and qualitative (pecky, atrophy, chalky and broken grains) damage during all panicle development. However, when the insects feed during anthesis/caryopsis and milky stage cause significantly greater percentage of empty grains (up to 83%) than when they feed of grains during later phases of panicle development. This characteristic was also observed for the reduction in grain weight. This information may benefit producers and other researchers, allowing them to focus on the monitoring efforts of O. poecilus in most susceptible phases of the attack of this insect. This will enable decision-making about what control measures should be taken, and when, in order to control stink bugs of panicles.

RESUMO Oebalus poecilus (Dallas 1851) é uma das espécies de percevejos de grande importância econômica para os produtores de arroz no Brasil em sistemas de cultivo irrigados, de inundação ou de terras altas. Estes pentatomídeos são conhecidos como percevejos das panículas, porque ninfas e adultos alimentam-se principalmente dessas estruturas. O ataque deste percevejo resulta em grãos manchados, massa inferior, redução germinativa e grãos deformados. Considerando isso, o objetivo deste estudo foi avaliar as perdas quantitativas e qualitativas na cultivar comercial de arroz de terras altas (variedade Cambará), submetidas a diferentes níveis de infestação de percevejos de panículas, O. poecilus, em diferentes estágios de crescimento reprodutivo das plantas de arroz. Os resultados mostram que em arroz de terras altas (variedade Cambará), os grãos de arroz são suscetíveis a danos quantitativos (número e peso) e qualitativos (grãos manchados, atrofiados, gessados e quebrados), durante todo o desenvolvimento da panícula. No entanto, quando os insetos se alimentam durante os estágios de antese/cariopse e leitosa causam percentual significativamente maior de grãos vazios (até 83%) do que quando se alimentam de grãos durante as fases posteriores do desenvolvimento da panícula. Esta característica foi também observada para a redução de peso dos grãos. Esta informação pode beneficiar os produtores e outros pesquisadores, permitindo que concentrem os esforços de monitoramento de O. poecilus em fases mais suscetíveis ao ataque deste inseto. Também serve de base para a tomada de decisão sobre quando e quais medidas de controle devem ser realizadas, a fim de controlar os percevejos das panículas.