Absorção de molibdênio pela cana de açúcar variedade Co 419, em função da idade

In this paper the authors describe the results obtained from the determination of molybdenum in sugar cane plant, grown in soils and climate prevailing in Piracicaba, State of São Paulo, Brazil. The molybdenum was determined in samples cut monthly from the 8th to 14th month, from an experiment consisting of 6 plots, 3 fertilized and 3 unfertilized. The fertilized treatment received 40 kg N (ammonium sulfate) 100 kg P2O3, (superphosphate) and 40 kg K2O (potassium chloride) per hectare, just before planting. Molybdenum was determined by thiocyanate-stannous chloride method, using carbon tetrachloride-butyl alcohol misture, for extrating the colored complex. The results obtained show a parallelism in the absorption of molybdenum by the plants of both treatments. The concentration of molybdenum in the stalks have a tendency to decrease, where as it kept more or less constant in leaves, with a exception in the 14° month when it rised probable because of a migration of molybdenum of the stalks to the leaves. The total amount molybdenum taken up was higher with the fertilized plot due its greater mass prodution.

Composition and diversity of bees (Hymenoptera) attracted by Moericke traps in an agricultural area in Rio Claro, state of São Paulo, Brasil

The composition and diversity of bees in an agricultural area in Rio Claro, state of São Paulo, Brazil, were studied from May 2003 to June 2004, using Moericke traps. The collection site, an area with 58.08 hectares, is characterized by grain production and direct planting, with 70% of the surrounding area planted with sugar cane. During the study, 456 bees were collected, distributed among 20 genera, pertaining to the families Andrenidae (4.8%), Apidae (40.8%) and Halictidae (54.4%). Specimens of genera Dialictus (38%) and Diadasia (30%) predominated in this area. The species diversity, assessed using the Shannon and Simpson indices, were H’=1.88 and 1/ D= 4.15, respectively, and the Evenness index was 0.61.

Estudos bionômicos de Dipetalogaster maximus (Uhler, 1894) (Hemiptera, Reduviidae, Triatominae): III. Dinâmica populacional

A population dynamics study of D. maximus was caried out under laboratory condictions (28-C e 65% ñ 5% U.R.) and the methodology was the same that have been used for hearing this insects. In order to evaluate the population growth rate of this species, during a 24 months period, five colonies started with a couple recently emerged were observed. Each couple (a male and a female) was mantained in a glass container measuring 20 cm of diameter and 20 cm in height with filter paper on the botton. The insects were monthly feeding with normal mice blood, and at this day the number of eggs, nymphal stages and adults was registered. All graphical representations of the populations growth rate showed the same shape. It was found that the average of nymphal stage represented 64.31% of the hole population whereas the oviposition curved showed to be inverse to this one (28.57%) a small percentage of adults was found: males 3.85% and females 3.12%. In this study observations on the biologycal cycle, longevity and fertility rates were also carried out.

Survival of tubercle bacilli in heat-fixed and stained sputum smears

We used a slide culture technique to detect tubercle bacilli surviving in sputum smears (n=46) after conventional heat fixation and Ziehl-Neelsen staining. In all heat-fixed sputum smears, tubercle bacilli survived after time 0 (n=22), 24 h (n=7), 48 h (n=7), 72 h (n=4), and seven days (n=6). None of the stained sputum smears showed growth on slide cultures. Viable tubercle bacilli remaining in heat-fixed sputum smears for at least seven days may present an infection risk to laboratory staff. Thus, sputum smears should be stained immediately by the Ziehl-Neelsen method or stored in a safe container to avoid transmission of tuberculosis.

Environmental characteristics of the cemeteries of Buenos Aires City (Argentina) and infestation levels of Aedes aegypti (Diptera: Culicidae)

Cemeteries with many water-filled containers, flowers, sources of human blood, and shade are favorable urban habitats for the proliferation of Aedes aegypti, a vector of yellow fever and dengue. A total of 22,956 containers was examined in the five cemeteries of the city of Buenos Aires, Argentina. The vector was found in four cemeteries that showed an average infestation level of 5.5% (617 positive out of 11,196 water-filled containers). The four cemeteries positive for Ae. aegypti showed significantly different (p<0.01) infestation levels. Vegetation cover and percentage of infestation were significantly correlated (p<0.01), but neither cemetery area nor number of available containers were significantly related to the proportion of positive vases. Our results suggest that the cemeteries of Buenos Aires represent a gradient of habitat favorableness for this vector species, some of which may act as foci for its proliferation and dispersal.

Suitability of containers from different sources as breeding sites of Aedes aegypti (L.) in a cemetery of Buenos Aires City, Argentina

Cemeteries are ideal urban areas to study the importance of different types of containers as breeding sites of Aedes aegypti (L.). In the present study, the suitability of plastic, glass, ceramic and metal containers was evaluated in four patches within a cemetery of Buenos Aires City, Argentina. Between October 1998 and May 2000, we found 215 breeding sites of Ae. aegypti out of 13,022 water-filled containers examined. In two patches containing microenvironments sheltered from the sun, the use of the different types of containers was proportional to the offer (correlation coefficient = 0.99, P < 0.05 in both cases). In the remaining patches, plastic and metal containers were the most and less frequent breeding sites, respectively (P < 0.001 in both cases). The number of immatures per breeding site (median = 4.5) did not show significant differences among the four types of containers examined (H3, 215 = 1.216, P = 0.749). Differences found in patches from a same cemetery suggest that different microenvironmental conditions affect the suitability of each type of container for Ae. aegypti breeding. Plastic containers appeared as key breeding sites that should be removed to reduce the Ae. aegypti population in the study area.

Evaluation of Mesocyclops annulatus (Copepoda: Cyclopoidea) as a control agent of Aedes aegypti (Diptera: Culicidae) in Argentina

We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.

A new miracidia hatching device for diagnosing schistosomiasis

It is still imperative to develop a parasitological technique highly sensitive for diagnosing schistosomiasis in epidemiological and individual surveys. A simple and cheap hatching device with a collecting container was manufactured and tested under experimental conditions. Twelve Kato-Katz slides were performed as golden standard for comparison. Quantitative results can be carried out by counting miracidia in a plate and parasite load can be calculated (miracidia/gram of feces). Statistically significant values were higher in the hatching test. More sensitive results, with statistical significance, were achieved using 1.5 g of feces (which corresponds to 36 Kato-Katz slides) than by using the Kato-Katz method. Advantages of this technique and its limitations are presented.

Mosquito traps designed to capture Aedes aegypti (Diptera: Culicidae) females: preliminary comparison of Adultrap, MosquiTRAP and backpack aspirator efficiency in a dengue-endemic area of Brazil

In this report, the efficiency of Adultrap under field conditions is compared to a CDC backpack aspirator and to MosquiTRAP. An urban dengue-endemic area of Rio de Janeiro was selected to evaluate the efficiency of mosquito traps in capturing Aedes aegypti females. Adultrap and aspirator captured similar numbers of Ae. aegypti females, with the former showing high specificity to gravid individuals (93.6%). A subsequent mark-release-recapture experiment was conducted to evaluate Adultrap and MosquiTRAP efficiency concomitantly. With a 6.34% recapture rate, MosquiTRAP captured a higher mean number of female Ae. aegypti per trap than Adultrap (Ç2 = 14.26; df = 1; p < 0,05). However, some MosquiTRAPs (28.12%) contained immature Ae. aegypti after 18 days of exposure in the field and could be pointed as an oviposition site for female mosquitoes. Both trapping methods, designed to collect gravid Ae. aegypti females, seem to be efficient, reliable and may aid routine Ae. aegypti surveillance.

Tire-breeding mosquitoes of public health importance along an urbanisation gradient in Buenos Aires, Argentina

Used vehicle tires are a source of mosquito vectors and a means of their introduction and expansion. With the aim of assessing the effects of urbanisation on the main mosquito vectors in temperate Argentina, the infestation levels of Aedes aegypti (L.) and Culex pipiens L. were studied in used tires from highly urbanised cities to low-urbanised small towns in Buenos Aires. Immatures of both species accounted for 96% of the 9,722 individuals collected; the total individuals collected represented seven species. The percentage of water-filled tires containing mosquitoes [container index (CI)] was 33% and the percentage of infested sites [site index (SI)] was 65.2%. These indexes decreased significantly from low to high urbanisation levels for both mosquito species. The relative abundance (RA) of Ae. aegypti immatures was slightly higher toward large cities, but showed no difference for Cx. pipiens. The CI of shaded tires was significantly higher than the CI of exposed tires for both mosquito species. There was no difference in RA values between shaded and sunlit tires. The CI and the SI were highest during the summer across the urbanisation levels, except for Cx. pipiens, which continued to increase during the autumn in small towns. Results related to urbanisation gradient, sunlit exposure and seasonality are discussed.

A comparative study of the TF-Test®, Kato-Katz, Hoffman-Pons-Janer, Willis and Baermann-Moraes coprologic methods for the detection of human parasitosis

This study compares the diagnostic accuracy of the TF-Test® (TFT) for human parasitosis with results obtained using the traditional Kato-Katz (KK), Hoffman-Pons-Janer (HPJ), Willis and Baermann-Moraes (BM) techniques. Overall, four stool samples were taken from each individual; three alternate-day TFT stool samples and another sample that was collected in a universal container. Stool samples were taken from 331 inhabitants of the community of Quilombola Santa Cruz. The gold standard (GS) for protozoa detection was defined as the combined results for TFT, HPJ and Willis coproscopic techniques; for helminth detection, GS was defined as the combined results for all five coproscopic techniques (TFT, KK, HPJ, Willis and BM). The positivity rate of each method was compared using the McNemar test. While the TFT exhibited similar positivity rates to the GS for Entamoeba histolytica/dispar (82.4%) and Giardia duodenalis (90%), HPJ and Willis techniques exhibited significantly lower positivity rates for these protozoa. All tests exhibited significantly lower positivity rates compared with GS for the diagnosis of helminths. The KK technique had the highest positivity rate for diagnosing Schistosoma mansoni (74.6%), while the TFT had the highest positivity rates for Ascaris lumbricoides (58.1%) and hookworm (75%); HPJ technique had the highest positivity rate for Strongyloides stercoralis (50%). Although a combination of tests is the most accurate method for the diagnosis of enteral parasites, the TFT reliably estimates the prevalence of protozoa and selected helminths, such as A. lumbricoides and hookworm. Further studies are needed to evaluate the detection accuracy of the TFT in samples with varying numbers of parasites.

Biological aspects of Leucothyreus alvarengai Frey and Leucothyreus aff. semipruinosus Ohaus (Coleoptera, Melolonthidae, Rutelinae) in crop succession at central Brazil

Biological aspects of Leucothyreus alvarengai Frey and Leucothyreus aff. semipruinosus Ohaus (Coleoptera, Melolonthidae, Rutelinae) in crop succession at central Brazil. Beetles of the family Melolonthidae make up a large group and some species are considered pests of planted crops. Little information is available on the basic biological aspects of the genus Leucothyreus, such as association with cultivated crops and their occurrence periods. Therefore studies were developed in soybean and corn crops in Tangará da Serra, Mato Grosso, Brazil, with the objective of studying the occurrence and biological aspects of Leucothyreus alvarengai Frey and Leucothyreus aff. semipruinosus Ohaus. For acquisition of immature specimens of both species, in April 2011 sampling was performed in corn fields, in July and October in the fallow area, and in soybeans fields planted in December; in 2012 sampling was performed in January and February in soybean fields and in March in corn fields. In 2011 the total number of larvae obtained in April, July, October and December were 100, 6, 30 and 27, and in January, February and March of 2012 these quantities were 32, 52 and 65 larvae, respectively. In all sampling events the larvae of L. alvarengai were collected in greater quantity. At the beginning of the reproductive period of L. alvarengai and L. aff. semipruinosus, it was observed that the adults began to fly and soon after started oviposition in the field in September. The appearance of larvae coincides with the time of soybean planting in the field, thus the larvae feed on roots of soybean plants at the beginning of their development and the cycle from egg to adult of the two species was completed in one year.

Growth and metabolic activity of the extramatrical mycelium of endomycorrhizal maize plants

The objective of this experiment was to quantify the extramatrical mycelium of the arbuscular mycorrhizal (AM) fungus Glomus etunicatum (Becker & Gerdemann) grown on maize (Zea mays L. var. Piranão) provided with various levels of phosphate fertilizer and harvested at 30, 60 and 90 days after planting (DAP). Total extramatrical mycelium (TEM) was extracted from soil using a modified membrane filtration method, followed by quantification using a grid intersection technique. Active extramatrical mycelium (AEM) proportion was determined using an enzymatic method which measured dehydrogenase activity by following iodonitrotetrazolium reduction. At low levels of added P, there was relatively less TEM than at high levels of added P, but the AEM proportion at low soil P availability was significantly greater than at high soil P.

Peanut response to lime and molybdenum application in low pH soils

Liming acid soils is considered to assure the availability of Mo in crops. Additionally, in peanuts (Arachis hypogaea L.) the positive response to liming is associated to a better supply of Ca+2, Mo for the nitrogenase-complex activity, and other non-nitrogen fixing activities of the crop. This study was thus undertaken to assess the effect of lime, Mo, and the lime-Mo interaction on peanut crop, on an acid Ultisol at the Mococa Experimental Station, Instituto Agronômico, São Paulo State, Brazil, from 1987 to 1990. A randomized complete block design with four replications, in a 4 x 4 factorial arrangement, was used in the study. The factors included four lime rates (0, 2, 4, and 6 t ha-1) broadcast and incorporated into the soil, and Mo (0, 100, 200, and 300 g ha-1) as (NH4)2MoO4 applied as seed dressing. Lime was applied once at the beginning of the study while Mo was applied at every planting. Peanut seed cv 'tatu' was used. Significant increase in peanut kernel yield with liming was only evident in the absence of Mo, whereas the peanut response to Mo was observed in two out of the three harvests. A higher yield response (28 % increase) was found when Mo was applied without liming. Soil molybdenum availability, as indicated by plant leaf analysis, increased significantly when lime was applied. Molybdenum fertilization led to higher leaf N content, which in turn increased peanut yield in treatments with smaller lime doses.

Peach palm growth and heart-of-palm yield responses to liming

The effects of liming rates on growth and heart-of-palm yield of peach palm plants (Bactris gasipaes Kunth) were studied in a two-year field experiment conducted in Pariquera-Açu, State of Sao Paulo, Brazil. Soils in this region are allic (sub group Ultic Haplorthox), with base saturation ranging from 15 to 26 % of the cation exchange capacity (CEC). A randomized complete block design, with five rates of dolomitic limestone (0, 0.7, 4.7, 8.7, and 14.6 Mg ha-1) and five replications was utilized. Individual plots were composed of 80 plants but only the inner rows (24 plants) were used for data recording. Planting spacing was 2 x 1 m. There was a cubic effect of liming rates on growth and yield. Maximum heart-of-palm yield was estimated to be achieved at 4.3 Mg ha-1 of limestone application, corresponding to 51.4 % soil base saturation. A significant decrease in growth and yield was observed when large amounts of limestone were applied (8.7 and 14.6 Mg ha-1), probably due to a decreased micronutrient availability.