The interaction between Poultry and Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae) in an experimental model

This paper compares the predation pressure that ducks and chickens exert on triatomines. For the tests, these birds were placed in individual boxes together with a known number of Triatoma infestans and left to interact from 6 p.m. till the next morning, involving a long lasting period of complete darkness limited by two short-term periods of semi-darkness. There was a shelter which could prevent the bugs from being predated. The number of live and dead triatomines was recorded, considering missing bugs as predated by the birds. Ducks exhibited a greater predatory activity than chickens, that could be due to a long term active period at night while chickens sleep motionless from sunset to dawn. Surviving triatomines that had fed on chickens outnumbered those fed on ducks suggesting that these were less accessible to the triatomine biting. If ducks are better than chickens to detect and eat bugs and to interfere with their feeding in the field, an increase in duck number might help to diminish triatomine density. Further research is needed to determine the feasibility of application of these experimental results.

Presence of Triatominae (Hemiptera, Reduviidae) and Risk of Transmission of Chagas Disease in Colima, México

With the purpose of evaluating the risk of transmission of the Chagas disease in the State of Colima, México, an entomological survey was performed to obtain triatominae and the rate of infection by Trypanosoma cruzi determined by examination of its dejections. Two hundred eighteen houses located in 16 villages were sampled. In each house the intradomestic and peridomestic habitats were examined by the man-hour-house method, sensor boxes and mouse-baited traps. Also, 12 silvatic places were explored around the same areas using the same techniques as the ones sampled. In total, 456 specimens were captured, of which 139 correspond to Triatoma phyllosoma pallidipennis; 80 to T. p. longipennis; one specimen of T. dimidiata and 236 nymphs of Triatoma sp. Two hundred ninety seven insects were captured in the intradomestic habitat, 132 in the peridomestic and 26 in the silvatic. The index of positive houses was 27%, located in the central area of the state. The rate of natural infection with T. cruzi showed 25.6%. This results confirmed the presence of two important vectors of the Chagas disease in Colima. Its preference for the domestic habitat and its high levels of natural infection with T. cruzi suggested the existence of a significant risk for its transmission in this area of the country.

Field trials of an improved cost-effective device for detecting peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae) in rural Argentina

An improved device for detecting peridomestic Triatoma infestans consisting of one-liter recycled Tetra Brik milk boxes with a central structure was tested using a matched-pair study design in two rural areas in Argentina. In Olta (La Rioja), the boxes were installed beneath the thatched roofs and on the vertical wooden posts of each peridomestic structure. After a 5-month exposure, at least one of the recovered boxes detected 88% of the 24 T. infestans-positive sites, and 86% of the 7 negative sites by timed manual collections at baseline. In Amamá (Santiago del Estero), the boxes were paired with the best performing prototype tested before (shelter unit). After 3 months, some evidence of infestation was detected in 89% (boxes) and 79% (shelters) of 18-19 sites positive by timed collections, whereas 19% and 16% of 32 negative sites were positive, respectively. Neither device differed significantly in the qualitative or quantitative collection of every sign of infestation. The installation site did not modify significantly the boxes' sampling efficiency in both study areas. As the total cost of each box was half as expensive as each shelter unit, the boxes are thus the most cost-effective and easy-to-use tool for detecting peridomestic T. infestans currently available.

Absence of domestic triatomine colonies in an area of the coastal region of Ecuador where Chagas disease is endemic

Rhodnius ecuadoriensis is considered the second most important vector of Chagas disease in Ecuador. It is distributed across six of the 24 provinces and occupies intradomiciliary, peridomiciliary and sylvatic habitats. This study was conducted in six communities within the coastal province of Guayas. Triatomine searches were conducted in domestic and peridomestic habitats and bird nests using manual searches, live-bait traps and sensor boxes. Synantrhopic mammals were captured in the domestic and peridomestic habitats. Household searches (n = 429) and randomly placed sensor boxes (n = 360) produced no live triatomine adults or nymphs. In contrast, eight nymphs were found in two out of six searched Campylorhynchus fasciatus (Troglodytidae) nests. Finally, Trypanosoma cruzi DNA was amplified from the blood of 10% of the 115 examined mammals. Environmental changes in land use (intensive rice farming), mosquito control interventions and lack of intradomestic adaptation are suggested among the possible reasons for the lack of domestic triatomine colonies.

No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae) and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae)

No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae) and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae). Biological traits of the stink bug Euschistus heros and its main biological control agent Telenomus podisi were evaluated under controlled environmental conditions (25 ± 2ºC; 60 ± 10% RH; and 14/10 h photoperiod) by placing first instar nymphs into Petri dishes with pods originating from two soybean isolines (Bt-soybean MON 87701 × MON 89788, which expresses the Cry1Ac protein, and its near non-Bt isoline A5547) where they remained until the adult stage. Due to gregarious behavior exhibited by first instar nymphs, they were individualized only when at the second instar. Adults were separated by sex and weighed, and pronotum width of each individual was subsequently measured. They were placed into plastic boxes containing soybean grains of the same soybean isoline as food source. Egg viability and female fecundity were assessed in adult individuals. Adult females of T. podisi (up to 24h old) were placed with eggs of E. heros from mothers reared on both soybean isolines. Nymphal development time, insect weight, pronotum width, sex ratio, female fecundity, and egg viability (% emergence) of Euschistus heros did not differ between treatments. Eggto-adult development time, female longevity, sex ratio, and percentage of parasitized eggs were not impacted by the Bt-soybean (expressing Cry1Ac protein). Results indicate that the Bt-soybean, MON 87701 × MON 89788, has no direct significant impact on the two studied species.

Incidência de ascite em frangos de corte alimentados com rações comerciais de alto nível energético

O trabalho objetivou avaliar os efeitos de diferentes rações comerciais com alto nível energético na incidência de ascite em frangos de corte. Foram utilizadas 1.200 aves de uma mesma linhagem comercial (Hubbard), distribuídas em 12 boxes, segundo um delineamento inteiramente ao acaso, com quatro tratamentos e três repetições de 100 aves cada. Os tratamentos foram constituídos por três diferentes rações comerciais trituradas (B, C e D) comparadas com o controle, uma ração farelada inicial (A), do primeiro ao 39º dia de idade. Não houve diferenças entre os tratamentos quanto ao consumo, peso e ganho de peso das aves. Em relação à conversão alimentar, o tratamento C apresentou resultado significativamente melhor; entretanto, foi observada neste mesmo tratamento, a maior taxa de mortalidade. O maior motivo dos óbitos registrados foi a síndrome ascítica. Conclui-se que existe um favorecimento de surto de ascite pelas rações com melhor conversão alimentar nas aves.

Incidência de ascite em diferentes categorias genéticas de frangos de corte alimentados com rações de alto nível energético

O objetivo deste trabalho foi verificar a incidência de ascite em avós, matrizes e frangos de corte, de uma mesma linhagem comercial, alimentados com ração de alto nível energético, de um dia a 39 dias de idade. Todas as aves foram criadas como frangos de corte, recebendo ração ad libitum com 3.050 kcal/EM; foram utilizadas aves da linha fêmea e linha macho e frangos de corte. Um total de 2.700 aves foram usadas, alojadas ao acaso em um galpão experimental de 8x76 m, utilizando-se 27 boxes de 3x3,5 m, com 100 aves por divisão, sendo três repetições por tratamento, em esquema fatorial. A incidência de ascite não dependeu da categoria genética das aves.

Suscetibilidade de linhagens de frangos de corte à síndrome ascítica

O objetivo deste trabalho foi estudar a suscetibilidade à síndrome ascítica de machos e fêmeas em linhagens comerciais de frango de corte. Todas as aves receberam ração ad libitum com 3.050 kcal/ME. Foram comparadas as linhagens comerciais representadas pela Cobb, Hubbard e Ross, machos e fêmeas. O delineamento utilizado foi o inteiramente casualizado, em esquema fatorial. As aves foram aleatoriamente alojadas em um galpão experimental de 8x76 m, com 18 boxes de 3x3,5 m cada e 100 aves por divisão, num total de 1.800 aves. Os resultados revelaram que a incidência de ascite independe da linhagem comercial dos frangos de corte, entretanto, os machos foram mais suscetíveis.

Interactions of juvenile Lumbricus terrestris with adults and their burrow systems in a two-dimensional microcosm

The objective of this work was to evaluate interactions of Lumbricus terrestris juveniles with adults and with inherited burrow systems. An experiment was set up using a two dimensional Evans' boxes microcosm. Adult L. terrestris were added to 16 boxes (one individual per box) and kept in darkness at 17ºC along with eight unoccupied boxes for two months. The adult L. terrestris were removed from eight randomly selected boxes, and L. terrestris juveniles were added (one juvenile per box), composing three treatments with eight replicates: 1, with an adult in an inherited burrow (ABJ); 2, alone in an inherited burrow (BJ); and 3, alone in a previously uninhabited box (J). The proportion of juveniles occupying adult burrows observed was significantly different in treatments ABJ (48%) and BJ (75%). The mean mass of juveniles at experimental termination differed significantly among treatments and was greater in treatment J (4.04±0.39 g) in comparison to the BJ (3.09±0.93 g) and ABJ treatments (2.13±0.64 g). Results suggest a negative influence of both the presence of an adult and its burrow system on juvenile growth. Intraspecific competition partially explained this, but further investigation is required to examine how an inherited environment (i.e. burrow) could negatively affect the growth of juveniles.

Biocontrol of seed pathogens and growth promotion of common bean seedlings by Trichoderma harzianum

The objective of this work was to evaluate isolates of Trichoderma harzianum regarding biocontrol of common bean seed-borne pathogens, plant growth promotion, and rhizosphere competence. Five isolates of T. harzianum were evaluated and compared with commercial isolate (Ecotrich), Carboxin+Thiram, and an absolute control. Bean seeds of the cultivar Jalo Precoce, contaminated with Aspergillus, Cladosporium, and Sclerotinia sclerotiorum, were microbiolized with antagonists, and seed health tests were carried out. Isolates were evaluated on autoclaved substrate and in field conditions. Ten days after sowing (DAS), plant length was measured. To test rhizosphere competence, isolates were applied in boxes containing autoclaved washed sand, and root colonization was evaluated at 10 DAS, using five plants per box. The most effective isolates in the seed health tests were: CEN287 and CEN289 to control Aspergillus; the commercial isolate to control Cladosporium; and CEN287 and CEN316 to control S. sclerotiorum. Isolates CEN289 and CEN290 promoted bean growth in greenhouse and field. Seed treatment with T. harzianum reduces the incidence of Aspergillus, Cladosporium, and S. sclerotiorum in 'Jalo Precoce' common bean seeds.

Germination and development of pecan cultivar seedlings by seed stratification

Abstract: The objective of this work was to evaluate the effect of seed stratification on germination rate, germination speed, and initial development of seedlings of six pecan (Carya illinoinensis) cultivars under subtropical climatic conditions in southern Brazil. For stratification, the seeds were placed in boxes with moist sand, in a cold chamber at 4°C, for 90 days. In the fourteenth week after sowing, the emergence speed index, total emergence, plant height, stem diameter, and number of leaves were evaluated. Seed stratification significantly improves the germination potential and morphological traits of the evaluated cultivars.

Principal components analysis for quality evaluation of cooled banana 'Nanicão' in different packing

This work aims determinate the evaluation of the quality of 'Nanicão' banana, submitted to two conditions of storage temperature and three different kinds of package, using the technique of the Analysis of Principal Components (ACP), as a basis for an Analysis of Variance. The fruits used were 'Nanicão' bananas, at ripening degree 3, that is, more green than yellow. The packages tested were: "Torito" wood boxes, load capacity: 18 kg; "½ box" wood boxes, load capacity: 13 kg; and cardboard boxes, load capacity: 18 kg. The temperatures assessed were: room temperature (control); and (13±1ºC), with humidity controlled to 90±2,5%. Fruits were discarded when a sensory analysis determined they had become unfit for consumption. Peel coloration, percentages of imperfection, fresh mass, total acidity, pH, total soluble solids and percentages of sucrose were assessed. A completely randomized design with a 2-factorial treatment structure (packing X temperature) was used. The obtained data were analyzed through a multivariate analysis known as Principal Components Analysis, using S-plus 4.2. The conclusion was that the best packages to preserve the fruit were the ½ box ones, which proves that it is necessary to reduce the number of fruits per package to allow better ventilation and decreases mechanical injuries and ensure quality for more time.

Fruit production in Chile: bright past, uncertain future

In 2007 (the last agricultural census), Chile had 308, 445 ha of fruit orchards: an increase of almost 32% from the previous census (1997). The most important species were table grapes (20%), avocados (13%) and apples (12%). Some 22% of the fruit crops growing area corresponded to juvenile orchards; within the species with higher proportion of juvenile orchards were prunes (42%) and blueberries (56%). Most orchards are located between latitude 27º18` S (Copiapó) and 40º36´S (Puerto Varas). The industry is driven by the export component which accounts for more than 50% of the fruits produced. In the crop season 2009-2010, approximately 254 million boxes (around 2.5 million tons) were exported, representing over US$ 3.5 million. Processed and fresh fruits represented 8.2 and 26.7% of the total forest and agricultural Chilean exports in 2008, respectively. The main markets for this fruits were USA/Canada (42%) and Europe (32%). The fruit grower receives, on average, 12-16% of the total price of the fruit in its final destination. Each year the fruit industry employs 450.000 people directly, of which 1/3 are permanent. Even though the fruit industry employs the highest proportion of the agricultural labor and the growing area has increased in the last 20 years, the proportion of agricultural employment has decreased from 19.5% in 1989 to 10.8% in 2008. It might also be noted that Chile invests only 0.7% of the GDP in research. In the last 40 years, the fruit industry has been a motor for the Chilean economic development, but the lower rates of currency exchange, the rising costs of energy (oil, electricity), and the increasing scarcity of hand labor have drastically reduced the profitability and are putting at risk the viability of a large proportion of the fruit orchards in Chile. It is estimated that this season around 65% of the orchards will have a negative economic balance in their operations. Higher investment in research, improvements in fruit quality and various orchard management practices, as well as higher financial support from the Government are needed for the long term viability of the fruit industry in Chile.

Estudo teórico das transições eletrônicas usando métodos simples e sofisticados

In this paper, the use of both simple and sophisticated models in the study of electronic transitions was explored for a set of molecular systems: C2H4, C4H4, C4H6, C6H6, C6H8, "C8", C60, and [H2NCHCH(CHCH)kCHNH2]+, where k = 0 to 4. The simple model of the free particle (1D, 2D, and 3D boxes, rings or spherical surfaces), considering the boundary conditions, was found to yield similar results to the sophisticated theoretical methods such as EOM-CCSD/6-311++G** or TD(NStates=5,Root=1)-M06-2X/6-311++G**.

Quantification of incubation, latent and infection periods of Phakopsora pachyrhizi in soybean, according to chronological time and degree-days

ABSTRACT In experiments conducted in a growth chamber, the chronological time and the accumulated degree-days were determined for the duration of incubation, latent and infectious periods of Phakopsora pachyrhizi cultivars BRSGO 7560 and BRS 246 RR. Detached soybean leaflets were placed in gerbox-type acrylic boxes and inoculated with 20 x 103 uredospores/mL. The study was conducted at 12-h photoperiod and temperatures of 10ºC, 15ºC, 22ºC, 25ºC and 30°C for 30 days. Lesions and uredia/cm2were evaluated and the number of uredia per lesion was quantified after the beginning of sporulation. The sporulation potential was also quantified for cultivars BRSGO 7560 and BRS 246 RR. The steps of the infection process can be quantified based on both the chronological time and the accumulated heat. The cultivar BRSGO 7560 produced 4,012.8 spores/cm2 and BRS 246 RR, 7,348.4 uredospores/cm2. The largest number of uredia was produced at 25ºC in both cultivars; however, BRS 246 RR presented 372.7 uredia/cm2 and BRSGO 7560, 231.6 uredia/cm2. At 10ºC and 30°C, leaf infection did not occur in both cultivars.