Suscetibilidade de duas Gramas-boiadeiras a diferentes formulações de glyphosate / Susceptibility of Cutgrass and Peruvian Watergrass to different glyphosate formulations

A utilização do herbicida glyphosate para o controle químico das espécies de gramas-boiadeiras nas lavouras orizícolas não tem se mostrado eficiente. Nesse contexto, a investigação do controle dessas espécies com o glyphosate torna-se de fundamental importância, uma vez que não estão disponíveis no mercado herbicidas seletivos para o controle dessas em pós-emergência na cultura do arroz irrigado. Em vista do exposto, o objetivo do presente estudo foi avaliar a suscetibilidade das gramas-boiadeiras a diferentes formulações de glyphosate. Foram conduzidos dois experimentos em casa de vegetação em esquema fatorial. No primeiro experimento, o fator A constituiu-se de duas formulações de glyphosate (sal potássico e isopropilamina) e o fator B de nove doses dos herbicidas (zero; 175; 350; 700; 1400; 2800; 5600; 11200; 22400g e.a. ha-1). No segundo experimento, o fator A constituiu-se de duas espécies de gramas-boiadeiras (Leersia hexandra e Luziola peruviana), o fator B de três formulações do glyphosate (sal amônio, potássico e isopropilamina) e o fator C de nove doses dos herbicidas (zero; 87,5; 175; 350; 700; 1400; 2800; 5600; 11200g e.a. ha-1). Com base nos resultados obtidos, foi possível observar que as espécies apresentaram diferença de suscetibilidade ao herbicida glyphosate. Além disso, Leersia hexandra foi mais sensível em comparação a Luziola peruviana. As formulações de glyphosate influenciaram na suscetibilidade das espécies ao controle, sendo que, Roundup Transorb R® e Roundup Ultra® proporcionam melhor controle das espécies de gramas-boiadeiras.

The use of glyphosate to chemical control of Cutgrass and Peruvian Watergrass with the use of non-selective herbicides has not been efficient. In this context, the investigation of chemical control of these species to glyphosate is very important, since there are not available commercially selective herbicides to control these species in post-emergence of irrigated rice. Therefore, the objective of this study was to evaluate the susceptibility of Cutgrass and Peruvian Watergrass to different formulations of glyphosate. Two factorial experiments were conducted in a greenhouse, in the first the A factor were two formulations of glyhposate (potassium and isopropylamine salt) and the B factor were nine doses of the herbicide (zero; 175; 350; 700; 1400; 2800; 5600; 11200; 22400g a.e. ha-1). In the second experiment, the A factor were two species (Leersia hexandra and Luziola peruviana), the B factor were three formulations of glyphosate (amoniun, potassium e isopropylamine salt) and the C factor were nine doses of herbicides (zero; 87,5; 175; 350; 700; 1400; 2800; 5600; 11200g a.e. ha-1). Based on the results obtained, it was observed that these species exhibit differential susceptibility to glyphosate. Moreover, Leersia hexandra was more sensitive when compared to Luziola peruviana. Glyphosate formulation influenced control efficiency, where Transorb Roundup R® and Roundup Ultra® provided the best control of the two species.

Transporte ascendente da mistura formulada de imazethapyr e imazapic em resposta à profundidade do lençol freático / Upward movement of the formulated mixture of imazethapyr and imazapic in response to height of the water table

Os herbicidas usados na cultura do arroz Clearfield® podem persistir no ambiente e causar danos no arroz não tolerante, cultivado em sucessão. Esse dano pode ser de intensidade variável, dependendo, dentre outros fatores, do movimento ascendente do herbicida para região de absorção do sistema radicular das plantas. O objetivo desta pesquisa foi verificar o efeito da altura do lençol freático no movimento ascendente do herbicida composto pela mistura formulada de imazethapyr e imazapic. Para isso, foram coletados lisímetros de solo com auxílio de tubos de PVC (15x30cm). O herbicida foi aplicado na superfície inferior dos lisímetros, onde foram simulados diferentes profundidades do lençol freático (0, 5, 10, 15 e 25cm da superfície do solo). Os lisímetros permaneceram nessa condição por período de 150 dias, quando foram cortados longitudinalmente, seccionados em porções de 5cm (0-5 a 25-30cm) e realizado bioensaio com a cultivar de arroz não tolerante, IRGA 417. Com os resultados obtidos, foi possível concluir que ocorre movimento ascendente da mistura formulada dos herbicidas imazethapyr e imazapic ao longo do perfil do solo de várzea durante o período da entressafra do arroz irrigado, sendo este maior quando o lençol freático está localizado mais próximo da superfície do solo. O movimento ascendente através da diluição do herbicida na solução do solo ocorre por fluxo de massa através do arraste pela água, transportada por capilaridade para zonas mais superficiais do solo.

The herbicides that use the Clearfield Rice System can persist in the environment and damage non-tolerant rice sowing in rotation. This damage can variable in intensity, depending on, among other factors, of the upward movement of the herbicide to the absorption region of the plant root system. The aim of this research was to verify the effect of the height of the water table in upward movement of the herbicide in intact soil cores. Intact soil cores were collected with PVC tubes 15cm in diameter and 30cm deep. The herbicide was applied on the bottom of the samples, and it was simulated water table depths (0, 5, 10, 15 and 25cm of the soil surface). The intact samples remained in this condition for a period of 150 days, when they were cut into 5cm slices (0-5 a 25-30cm) and bioassay were performed with the non-tolerant rice cultivar. With the results it was conclude that there is upward movement of the formulated mixture of imazethapyr and imazapic herbicides along the paddy soil profile during the fallow and this transport is greater when the water table is located closer to the soil surface. The upward movement by dilution of the herbicide in the soil solution occurs by mass flow through the water transported by capillarity to superficial sites of soil.

Temporal differences in blood meal detection from the midguts of Triatoma infestans / Diferencias temporales en la detección de fuentes de alimentación en el contenido intestinal de Triatoma infestans

We used genus/species specific PCRs to determine the temporal persistence of host DNA in Triatoma infestans experimentally fed on blood from six common vertebrate species: humans, domestic dogs, guinea pigs, chickens, mice, and pigs. Twenty third or fourth instar nymphs per animal group were allowed to feed to engorgement, followed by fasting-maintenance in the insectary. At 7, 14, 21, or 28 days post-feeding, the midgut contents from five triatomines per group were tested with the respective PCR assay. DNA from all vertebrate species was detected in at least four of five study nymphs at seven and 14 days post-feeding. DNA of humans, domestic dogs, guinea pigs, pigs, and chickens were more successfully detected (80-100%) through day 21, and less successfully (20-100%) at day 28. Findings demonstrate that species-specific PCRs can consistently identify feeding sources of T. infestans within two weeks, a biologically relevant time interval.

Se utilizó pruebas PCR género o especie específicas para determinar la persistencia temporal de ADN del hospedero en el contenido intestinal de Triatoma infestans que fueron alimentados experimentalmente con sangre de seis vertebrados muy frecuentemente asociados a enfermedad de Chagas: humano, perro, cobayo, pollo, ratón, y cerdo. Se emplearon 20 ninfas de tercer y cuarto estadio por cada especie de hospedero. Fueron alimentados a saciedad y mantenidas en el insectario sin alimentación posterior. Se obtuvo el contenido intestinal de cinco triatominos por cada grupo a los 7, 14, 21 y 28 días post - alimentación, que fueron evaluados con los respectivos PCRs específicos. El ADN de todos los vertebrados fue detectado en al menos 4 de 5 ninfas evaluadas a los 7 y 14 días post - alimentación. El ADN de humano, perro, cobayo, cerdo y pollo fue detectado exitosamente (80-100%) hasta el día 21 y con menos éxito (20-100%) en el día 28. Estos resultados demuestran que PCRs específicos para cada especie de hospedero pueden identificar consistentemente la fuente de alimentación de T. infestans dentro de las dos semanas post - alimentación, siendo un intervalo de tiempo biológicamente relevante.

Aspectos entomológicos de la enfermedad de chagas en Huallaga y Picota, San Martín, Perú / Entomological aspects of chagas disease in Huallaga and Picota, San Martin, Peru

Introducción: Existe escasa información y no actualizada sobre la presencia de triatominos en el departamento de San Martín, zona amazónica de nuestro país, y es importante actualizarla, ya que hay reportes recientes de casos de enfermedad de Chagas procedentes de la amazonía peruana cuyos vectores serían triatominos silvestres. Objetivos: Conocer la distribución geográfica de triatominos hematófagos en Huallaga y Picota, San Martín, Perú. Determinar los índices entomológicos, sus hábitos alimenticios y caracterizar los tripanosomatídeos que portan. Diseño: Investigación descriptiva observacional. Lugar: Red de Salud Huallaga y Picota, Laboratorio Regional de la Región de Salud San Martín. Laboratorios del Instituto Nacional de Salud. Participantes: Viviendas de 6 distritos de las provincia de Huallaga y 9 de Picota, del Departamento de San Martín. Intervenciones: La búsqueda de triatominos fue en 3 362 viviendas de áreas periurbanas y rurales. Mediante la prueba de precipitina, se determinó la fuente de alimentación. Se aisló tripanosomatídeos mediante infección en ratones Balb/C e inoculación en medio agar sangre, y por PCR se caracterizó el genoma por amplificación del espaciador intergénico del gen miniexón. Principales medidas de resultados: Determinar si Huallaga y Picota, San Martín, Perú, son zonas de riesgo de enfermedad de Chagas. Resultados: En 46 viviendas, de 3 362 muestreadas se capturó 53 triatominos adultos pertenecientes a Rhodnius pictipes (56,6 por ciento), Panstrongylus geniculatus (41,5 por ciento) y Eratyrus mucronatus (1,9 por ciento). Se reporta P. geniculatus por primera vez para las dos provincias. Los índices de infestación para ambas provincias fueron 1,4 por ciento y 3,8 por ciento, respectivamente, y corresponden al índice de infección natural; mientras que el índice de dispersión fue 30,1 por ciento. En R. pictipes se identificó cinco fuentes de alimentación (pollo, humano, perro, cobayo y gato) y en P. geniculatus un perfil alimentario mixto: perro/gato/pollo. Los Trypanosoma spp. aislados de R. pictipes, procedente de Sacanche (Huallaga), corresponden a TCI (350 pb); resultado similar se obtuvo en los 10 clones de este aislamiento. Conclusiones: Los resultados nos indican que, en las localidades estudiadas, R. pictipes y P. geniculatus estarían pasando por un proceso de domiciliación y que en las localidades de Huallaga R. pictipes sería el principal vector de Trypanosoma cruzi TC1; por lo que, dichas localidades estarían consideradas como zonas de riesgo de enfermedad de Chagas.

Introduction: There is little and not recent information on the presence of triatomine bugs in San Martin department, Amazon area of our country where Chagas disease has been reported by wild triatomine insects as vectors. Objectives: To determine the geographic distribution of hematophagous triatomine insects in Huallaga and Picota provinces, San Martin department, Peru. To determine the domiciliary infestation by triatomine vectors indexes, trypano-triatomine infection as well as their dispersion. To determine the insects feeding source and to genetically characterize the tripanosomatidae they carry. Design: Observational and descriptive study. Setting: Health and Laboratories region networks. National Institute of Health laboratories. Participants: Houses from 6 districts of Huallaga province and 9 from Picota province (San Martin department). Interventions: Triatomine insectÆs collection was carried out in 3 362 homes located in semi-urban and rural zones accounting for 30 per cent of the total area of studied provinces. Feeding preferences were assessed by a precipitin test using specific antibodies against guinea pig, dog, cat, chicken and human beings sera. Trypanosomes were isolated by inoculation of stool samples from infected insects in Balb/c mice and using axenic culture media. Genetic characterization was done by PCR amplification of the genome by gene intergenic spacer of the miniexon. Main outcome measures: To assess if Huallaga and Picota, San Martin, Peru, are Chagas disease risk areas. Results: In 46 of the 3 368 homes visited, 53 triatomine adults were collected belonging to the species Rhodnius pictipes (56,6 per cent), Panstrongylus geniculatus (41,5 per cent) and Eratyrus mucronatus (1,9 per cent). For the first time, P. geniculatus was reported in both provinces included in the study. Domiciliary infestation index was 1,4 per cent, trypano-triatomine infection index was 3,8 per cent and dispersion index was 30,1 per cent. For R. pictipes 5 sources of food were identified (chicken, human, dog, guinea pig and cat) and for P. geniculatus, a mix feed: dog, cat and chicken. Trypanosoma spp. isolates of R. pictipes from Sacanche (Huallaga) belonged to T. cruzi TCI (350 pb); similar result was obtained in 10 clones studied. Conclusions: Results indicate that R. pictipes and P. geniculatus are undergoing colonization of the regions included in this study. Within the province of Huallaga, R. pictipes is the predominant vector of T. cruzi; therefore these locations must be considered high risk areas for Chagas disease.

Fuentes de alimentación de panstrongylus herreri (hemiptera: Triatominae) capturados en utcubamba, amazonas - perú / Food sources of panstrongylus herreri (hemiptera: triatominae) collected in utcubamba, Amazonas - Peru

Objetivo. Identificar las fuentes de alimentación de Panstrongylus herreri, procedente del distrito de Cajaruro, provincia de Utcubamba, departamento de Amazonas. Materiales y métodos. El estudio se realizó en dos etapas: primera, se estandarizó la prueba de precipitina usando como antígenos sueros sanguíneos de: humano, perro, gato, cobayo y pollo, y anticuerpos específicos obtenidos por inoculaciónde los antígenos en conejos. Se alimentaron ninfas de Triatoma infestans del IV y V estadio criadas en laboratorio con sangre de perro,cobayo, pollo y humano para luego determinar la sensibilidad y especificidad de la prueba. Segunda, se aplicó la prueba de precipitina a 102ejemplares de P. herreri domiciliarios, procedentes de la zona de estudio. Resultados. Se obtuvo títulos de anticuerpos desde 1:10 000 a1:30 000. La especificidad de la prueba fue 100 por ciento para todos los intervalos de tiempo evaluados; mientras, que la sensibilidad varió de 70 a 100 por ciento. De los 102 P. herreri, en 93 ejemplares se detectó contenido intestinal y se encontró la fuente alimenticia en 77 de ellos, la sangre de cobayo (36,3 por ciento) fue la principal fuente de alimentación, seguido de humano (18,2 por ciento) y pollo (14,3 por ciento). El índice de infección tripano-triatomíno fue 62,4 por ciento. Conclusiones. La prueba de precipitina mostró mejor especificidad que sensibilidad. En las áreas de estudio, la fuente principal de alimentación de P. herreri es la sangre de cobayo, seguido del humano y pollo. El elevado índice de infección a Trypanosoma sp. relacionado con la fuente de alimentación por cobayo, nos indicaría que es el principal reservorio.

Objective. To identify the food sources of Panstrongylus herreri from district of Cajaruro, province of Utcubamba, department of Amazonas. Material and methods. The study was performed in two steps: in the first, a precipitin test was standardized using as antigen, blood sera from human being, dog, cat, guinea pig and chicken and the specific antibodies obtained by inoculation of the antigens in rabbits. Nymphs of Triatoma infestans (IV and V instars)maintained in the laboratory were fed on dog, cat, guinea pig, and human being to determine the sensitivity and the specificity of the precipitin test. In the second step, 102 P. herreri specimens collected from houses of the two villageswere submitted to the standardized precipitin test. Results. The developed test permitted good titles of antibodies in the range from 1:10 000 to 1:30 000. The specificity was 100 per cent and the sensitivity was 70 per cent to 100 per cent. Of the 102 P. herreri specimens were detected intestinal content in 93 and found the food source in 77 of them, the blood of guinea pig (36.3 per cent) was the main source of food, followed by human (18.2 per cent) and chicken (14.3 per cent).The Trypano-triatomine index was 62.4 per cent. Conclusions. The precipitin test showed better specificity than sensitivity. In this study sites, the main food source of P. herreri was guinea pig follow by the human being and chicken. The high rate of insects carrying Trypanosoma sp. was related to the insects fed on guinea pig pointing it out as reservoir of the parasite.

Características morfométricas, genéticas, alimenticias y vectoriales de Panstrongylus herreri procedentes de Jaén (Cajamarca) y Cajaruro Amazonas), Perú / Morphometric, genetic, FEEDING and vectorial characteristics of Panstrongylus herreri from Jaén (Cajamarca) and Cajaruro (Amazonas), Peru

Objetivo. Comparar las características morfológicas, alimenticias y genéticas de dos poblaciones de Panstrongylusherreri, de los distritos de Jaén (Cajamarca) y Cajaruro (Amazonas). Materiales y métodos. Se colectó especímenes adultos de P. herreri, 42 (Jaén) y 68 (Cajaruro). Se utilizó la morfometría geométrica para evaluar el dimorfismo sexual de tamaño y conformación. El perfil genómico se realizó por amplificación del espaciador interno transcrito del ADNr(ITS-2). La amplificación del espaciador intergénico del gen mini-exón, permitió la caracterización molecular de lostrypanosomas aislados. Se utilizó la prueba de precipitina para conocer las fuentes de alimentación de los vectores y así poder asociarlos a posibles reservorios del parásito. Resultados. El análisis morfométrico demostró que el dimorfismo sexual de tamaño fue similar (p > 0,05); no ocurrió lo mismo con el dimorfismo de la conformación; asimismo no se encontró diferencias de tamaño al comparar por separado hembras y machos de Jaén y Cajaruro. Por ITS-2, se evaluó cinco especímenes de cada distrito, en ellos se observó una banda de 960 pb aproximadamente. Sólo en Cajaruro se encontraron triatominos parasitados, que fue caracterizado como Trypanosoma cruzi TCI (350 pb). Se identificó al cobayo como la fuente de alimento más frecuente. Conclusiones. Ambas poblaciones de P. herreri por morfometría geométrica e ITS-2, no evidenció diferencias, indicando que se trataría de una misma población y por consiguiente de la misma procedencia. La sangre de cobayo fue la más frecuente fuente de alimento, pudiendo ser el principal reservorio para la enfermedad de Chagas en esta zona del Perú.

Objective. To compare the morphology, feeding and the genetic profile of specimens of Panstrongylus herreri from districts of Jaen (Cajamarca) and Cajaruro (Amazonas). Material and methods. Adult specimens of P. herreri were collected, 42 from Jaen and 68 from Cajaruro. Geometric morphometrics was used to evaluate the sexual differences in size and form. The genetic profile was done using the PCR amplification, second internal transcribed spacer (ITS-2) of theribosomal ADN. The molecular characterization of the isolated trypanosomes was made by the amplification the parasite. We used the precipitin test for identification the feeding sources and thus be able to associate them with the potential reservoir of the parasite. Results. The morphometric analyses showed no difference (p > 0,05) in sex between the insects from both departments, but there was difference in the form between females. The genetic profile showed by ITS-2 similar bands of 960 pb in both groups (five insects) from Jaen and Cajaruro. The trypanosoma isolated from P. herreri (only in Cajaruro) was identify as Trypanosoma cruzi TCI (350 pb). Guinea pig blood was the main source of food for the insects. Conclusions. P. herreri from both localities no showed important differences under geometric morphometry and genetic studies. These results indicate the same population with similar origin. The guinea pig blood was the main source of food of P. herrei, may be the principal reservoir for the Chagas disease from this Peruvian area.