Comparing Host Plant Resistance, Repellent Mulches, and At-Plant Insecticides for Management of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) and Tomato Yellow Leaf Curl Virus.

Bemisia tabaci MEAM1 (Gennadius), the sweetpotato whitefly, transmits Tomato yellow leaf curl virus (TYLCV), which causes significant yield losses annually in Florida and other tomato-producing regions. Field trials were carried out at the University of Florida's Gulf Coast Research and Education Center to evaluate integration of plastic mulch type, at-plant insecticide, and tomato variety for management of the sweetpotato whitefly and TYLCV. The tomato varieties Charger, Rally, and Tygress had significantly lower season-long densities of whitefly eggs and nymphs than Florida-47 in one or more trials. Aggressive chemical control measures failed to reduce virus incidence in two of the three trials and did not improve yield. In 2013, when virus pressure was extremely high, yield in the susceptible variety was decimated, but virus-tolerant varieties produced a crop. Egg and nymph densities tended to be lowest on TYLCV-tolerant varieties and on tomato grown on metalized mulch. Differences in yield were primarily due to tomato variety and TYLCV incidence. Intensive insecticide use common in Florida tomato production may reduce losses when viral pressure is moderate, but not when migration of viruliferous whiteflies into the field is constant. Without significant winter freezes or a coordinated host-free period to reduce whitefly populations, insecticidal control and repellent-metalized mulches will offer limited protection compared with genetic tolerance to the virus, which may also be overcome under high virus pressure.

The Invasive Liriomyza huidobrensis (Diptera: Agromyzidae): Understanding Its Pest Status and Management Globally.

Liriomyza huidobrensis (Blanchard) is native to South America but has expanded its range and invaded many regions of the world, primarily on flowers and to a lesser extent on horticultural product shipments. As a result of initial invasion into an area, damage caused is usually significant but not necessarily sustained. Currently, it is an economic pest in selected native and invaded regions of the world. Adults cause damage by puncturing abaxial and adaxial leaf surfaces for feeding and egg laying sites. Larvae mine the leaf parenchyma tissues which can lead to leaves drying and wilting. We have recorded 365 host plant species from 49 families and more than 106 parasitoid species. In a subset of the Argentinian data, we found that parasitoid community composition attacking L. huidobrensis differs significantly in cultivated and uncultivated plants. No such effect was found at the world level, probably due to differences in collection methods in the different references. We review the existing knowledge as a means of setting the context for new and unpublished data. The main objective is to provide an update of widely dispersed and until now unpublished data, evaluate dispersion of the leafminer and management strategies in different regions of the world, and highlight the need to consider the possible effects of climate change on further regional invasions or expansions.

Susceptibility of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) to Imidacloprid, Thiamethoxam, Dinotefuran and Flupyradifurone in South Florida.

Populations of Bemisa tabaci MEAM1 were established from nineteen locations in south Florida, primarily from commercial tomato fields, and were tested using a cotton leaf petiole systemic uptake method for susceptibility to the nicotinic acetylcholine agonist insecticides imidacloprid, thiamethoxam, dinotefuran and flupyradifurone. Eleven populations produced LC50s for one or more chemicals that were not significantly different from the susceptible laboratory colony based on overlapping fiducial limits, indicating some degree of susceptibility. LC50s more than a 100-fold the laboratory colony were measured in at least one population for each material tested, indicating tolerance. LC50s (ppm) from field populations ranged from 0.901-24.952 for imidacloprid, 0.965-24.430 for thiamethoxam, 0.043-3.350 for dinotefuran and 0.011-1.471 for flupyradifurone. Based on overlapping fiducial limits, there were no significant differences in relative mean potency estimates for flupyradifurone and dinotefuran in relation to imidacloprid and thiamethoxam.

Seroprevalence of Trypanosoma cruzi infection in three rural communities in Guatemala / Seroprevalencia de infección por Trypanosoma cruzi en tres comunidades rurales de Guatemala

A systematic, house-based serological survey for Trypanosoma cruzi seroreactivity was conducted in three contiguous communities in Olopa municipality, Chiquimula Department, Guatemala. Blood samples from a total of 292 individuals in 63 households were examined by enzyme-linked immunosorbent assay. The seropositive rate ranged from 0 x cent to 20.8 x cent for the three communities, with a mean of 15.1 x cent. Log-linear models showed that seroprevalence was significantly related to age (P<0.005) but not to sex. However, when the age group with the lowest prevalence (1-9 years) was excluded from the analysis, age was not a significant factor (P=0.55). Data from a stratified sample collected at the same time were combined with those of the systematic sample to analyze the relationship between seropositivity and possible explanatory variables. Log-linear models, based on 586 individuals in 129 households from the two surveys, revealed a significant positive association between seropositivity and thatched roofs (P=0.01)

Una encuesta serológica sistemática y domiciliaria para detectar serorreactividad a Trypanosoma cruzi se llevó a cabo en tres comunidades contiguas de la municipalidad de Olapa, en el departamento de Chiquimula, Guatemala. Se examinaron mediante inmunoadsorción enzimática muestras de sangre obtenidas de un total de 292 habitantes que residían en 63 viviendas. La tasa de seropositividad varió de 0 a 20,8% en las tres comunidades y tuvo una media de 15,1%. Los modelos logarítmico-lineales mostraron una asociación significativa entre la seroprevalencia y la edad (P < 0,05), pero no entre aquella y el sexo. No obstante, cuando el grupo de edad que tuvo la seroprevalencia más baja (el de 1 a 9 años) se excluyó del análisis, la edad dejó de ser un factor significativo (P = 0,55). Datos obtenidos de una muestra estratificada recogida simultáneamente se combinaron con los de la muestra sistemática con el fin de analizar la relación entre la seropositividad y algunas variables que podrían ser explicativas. Los modelos logarítmico-lineales, aplicados en 586 habitantes de 129 viviendas incluidas en ambas encuestas, revelaron una asociación positiva significativa entre la seropositividad y la presencia de techo de paja (P = 0,01)

Seroprevalence of Trypanosoma cruzi infection in three rural communities in Guatemala

A systematic, house-based serological survey for Trypanosoma cruzi seroreactivity was conducted in three contiguous communities in Olopa municipality, Chiquimula Department, Guatemala. Blood samples from a total of 292 individuals in 63 households were examined by enzyme-linked immunosorbent assay. The seropositive rate ranged from 0 x cent to 20.8 x cent for the three communities, with a mean of 15.1 x cent. Log-linear models showed that seroprevalence was significantly related to age (P0.005) but not to sex. However, when the age group with the lowest prevalence (1-9 years) was excluded from the analysis, age was not a significant factor (P=0.55). Data from a stratified sample collected at the same time were combined with those of the systematic sample to analyze the relationship between seropositivity and possible explanatory variables. Log-linear models, based on 586 individuals in 129 households from the two surveys, revealed a significant positive association between seropositivity and thatched roofs (P=0.01)