Sustainable weed management on ornamental beds

The weed presence on ornamental beds is a main aspect that interferes with the garden maintenance, especially in tropical countries, as it causes an unpleasant effect and competes with the ornamentals. The use of herbicides is not always economically viable, besides, it causes phytotoxic effects on the ornamental plants, so the alternative to minimize this problem is the use of mulch; however, there is little information on the literature about it. Thus, the aim of this work was to evaluate the effect of rice straw mulching on the weed management of Salvia splendens beds. There were four treatments (0, 4, 6 and 8 t ha-1 of rice straw) and five replications. Brachiaria decumbens (200 plants m-2) and Amaranthus viridis (50 plants m-2) were sown in each plot in order to ensure the weed presence. The evaluation of the weed community was performed 60 days after sowing. The weeds on the plots of 0.48 m2 were identified and removed by hand and then dried in a chamber of forced air ventilation (under 703C) for the dry matter determination which later helped to calculate the phytosociological indexes like the Relative Density, Relative Frequency, Relative Dominance and the Importance Value Index. Nineteen species of weeds were identified. Among them, B. decumbens and A. viridis presented the highest Relative Importance level and the use of 8 t ha-1 of rice straw mulching helped to minimize the Relative Importance of these plants; however, the weed management with the use of rice straw was not effective.

The Phylogeographic History of the New World Screwworm Fly, Inferred by Approximate Bayesian Computation Analysis

Insect pest phylogeography might be shaped both by biogeographic events and by human influence. Here, we conducted an approximate Bayesian computation (ABC) analysis to investigate the phylogeography of the New World screwworm fly, Cochliomyia hominivorax, with the aim of understanding its population history and its order and time of divergence. Our ABC analysis supports that populations spread from North to South in the Americas, in at least two different moments. The first split occurred between the North/Central American and South American populations in the end of the Last Glacial Maximum (15,300-19,000 YBP). The second split occurred between the North and South Amazonian populations in the transition between the Pleistocene and the Holocene eras (9,100-11,000 YBP). The species also experienced population expansion. Phylogenetic analysis likewise suggests this north to south colonization and Maxent models suggest an increase in the number of suitable areas in South America from the past to present. We found that the phylogeographic patterns observed in C. hominivorax cannot be explained only by climatic oscillations and can be connected to host population histories. Interestingly we found these patterns are very coincident with general patterns of ancient human movements in the Americas, suggesting that humans might have played a crucial role in shaping the distribution and population structure of this insect pest. This work presents the first hypothesis test regarding the processes that shaped the current phylogeographic structure of C. hominivorax and represents an alternate perspective on investigating the problem of insect pests. © 2013 Fresia et al.

Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

Das folhas de Deguelia utilis foram isolados cinco flavonoides: 5,3'-di-hidróxi-4'-metóxi2'',2''-dimetilcromeno-(5'',6'':6,7)-di-hidroflavonol (1), 5,3'-di-hidróxi-7,4'-dimetóxi-6,8dimetilalil-di-hidroflavonol (2), 5,3'-di-hidróxi-4'-metóxi-8-prenil-2'',2''-dimetilcromeno(5'',6'':6,7)-flavanona (3), 5,3'-di-hidróxi-7,4'-dimetóxi-6,8-dimetilalil-flavanona (4), 3,5,3'-tri-hidróxi-7,4'-dimetóxi-6,8-dimetilalil-flavanol (5), juntamente com os estilbenos: 4-metoxilonchocarpeno (6) e lonchocarpeno (7). Suas estruturas químicas foram elucidadas com base nos seus dados de NMR (ressonância magnética nuclear) e HRESITOF-MS (espectrometria de massas de alta resolução por tempo de vôo, com ionização por eletrospray). Além disso, a fim de investigar o potencial efeito citoprotetor desses flavonoides, foi utilizada uma fração eluída com hexano:AcOEt contendo os sete flavonoides, em um modelo in vitro de neurodegeneração, utilizando culturas primárias do hipocampo de ratos neonatal (PND2-P3) expostos à rotenona, um inibidor mitocondrial do complexo I. Houve uma redução significativa da viabilidade celular (19,4 ± 1,6%), quando as culturas foram expostas à rotenona 30 nmol L^-1 por 72 h. A exposição concomitante das culturas a FR3 (5 µg mL^-1) e rotenona 30 nmol L^-1 resultou em valores de viabilidade celular semelhante ao grupo controle (99,6 ± 4,8%), sugerindo um efeito citoprotetor para essa fração.

Ultrastructural description of Ceratomyxa microlepis sp. nov. (Phylum Myxozoa): a parasite infecting the gall bladder of Hemiodus microlepis, a freshwater teleost from the Amazon River

A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. The sporoplasm was binucleate. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. nov.; therefore representing the first description of a freshwater ceratomyxid from the South American region.

Impact of the timing and duration of weed control on the establishment of a rubber tree plantation

A produção da seringueira é reduzida pelas plantas daninhas que competem por recursos ambientais; portanto, a época e duração do controle de plantas daninhas influencia a interferência das plantas daninhas. Os objetivos deste estudo foram: avaliar o crescimento de plantas de seringueira (Hevea brasiliensis), determinar o período crítico para controle das plantas daninhas e avaliar a recuperação do crescimento das seringueiras que conviveram com plantas daninhas por diferentes períodos de tempo após o plantio. Dois grupos de tratamentos foram estabelecidos em condições de campo, no primeiro ano de investigação: um grupo conteve períodos crescentes de infestação de plantas daninhas, enquanto o outro conteve períodos crescentes de controle das plantas daninhas, também incluindo uma testemunha livre de plantas daninhas e uma testemunha com infestação total de plantas daninhas. No segundo ano da investigação, as plantas daninhas foram totalmente controladas. Urochloa decumbens foi a planta daninha dominante (mais de 90% de cobertura). O crescimento da cultura foi grandemente reduzido devido à interferência de plantas daninhas. A altura de plantas decresceu mais rapidamente que qualquer outra característica. Altura de planta, massa seca de folhas e área foliar decresceram em 99%, 97% e 96%, respectivamente, e foram as características mais reduzidas. A altura de plantas também se recuperou mais rapidamente que qualquer outra característica quando o período de controle das plantas daninhas foi entendido. Contudo, a massa seca do caule aumentou em 750%, fazendo desta a característica mais recuperada. O período crítico para o controle de plantas daninhas foi entre 4 e 9½ meses após o plantio, no primeiro ano; contudo, as seringueiras mostraram expressiva recuperação do crescimento quando as plantas daninhas foram controladas ao longo do segundo ano.

Genetic variability among Commelina weed species from the states of Paraná and São Paulo, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efficiency of partial treatment of cattle infested with horn fly using 40% diazinon

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Behavior of Montandoniola confusa Streito & Matocq (Hemiptera: Anthocoridae) preying upon gall-forming thrips Gynaikothrips ficorum Marchal (Thysanoptera: Phlaeothripidae)

The gall-forming thrips Gynaikothrips ficorum Marchal (Thysanoptera: Phlaeothripidae) is recorded in all regions where its host plant, Ficus microcarpa (Marchal) (Moraceae), has been cultivated as an urban and interior landscape plant species, including potted plants and bonsai. Similarly, the thrips predator Montandoniola confusa Streito & Matocq (Hemiptera: Anthocoridae) has generally followed the prey distribution. The gall induced by thrips degrades the plant foliage, and the thrips themselves can be annoying for people both outdoors and indoors. The galls, however, create a microcosm with all developmental stages of the thrips and its predator. In this study we present the first records of M. confusa in South America, document the species' widespread concomitant occurrence across Brazil, and report our studies of three aspects of M. confusa predation upon the eggs, larvae/prepupae, and adults of G. ficorum thrips: (i) functional response of the predator adult female as a function of different densities of thrips eggs, larvae/prepupae and adults separately: (ii) predation on eggs by adult M. confusa with adult thrips present in the gall; and (iii) adult M. confusa prey preferences when all thrips stages occurred simultaneously in the gall. For all three thrips life stages tested, the predator exhibited a type II functional response. Despite the availability of different life stages in the gall, M. confusa adults are capable of preying upon all life stages of G. ficorum, predation was preferentially on thrips eggs, with an estimated similar to 10-fold greater predation on eggs compared to larvae/prepupae and adult thrips. Egg predation was unaffected by the presence of defensive adult thrips in the gall under low densities (<30 eggs/gall) but when egg densities were greater than 30 eggs/gall, it was reduced when adult thrips were present. However, the relative number of thrips adults per gall did not statistically change the outcome. (C) 2013 Elsevier Inc. All rights reserved.

Genetic diversity and population structure of the New World screwworm fly from the Amazon region of Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chitosan/tripolyphosphate nanoparticles loaded with paraquat herbicide: An environmentally safer alternative for weed control

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

INFLUENCE OF NOZZLE TYPE AND SPRAY RATES ON CORN AND WEED PLANTS DROP DEPOSITIONS

The objective of this study was to evaluate different nozzles and spray rates on drop deposition in corn (Zea mays), Euphorbia heterophylla and Brachiaria plantaginea, both weeds located at and between crop rows. The experimental design established was complete random blocks with treatments arranged at 2 x 2 factorial scheme (2 nozzles types: DG11002VS flat flan and medium droplets, TXVK08 cone and very fine droplets; and 2 rates: 100 and 200 L ha(-1)) with four replications. The spray applications occurred at 13 days after corn germination (3-5 expanded leaves), when E. heterophylla and B. plantaginea plants had 2-4 and 2-3 leaves, respectively. Solution of Brilliant Blue (FD&C-1) dye at 3,000 ppm was used as spray tracer. It was concluded that the greatest average deposits in corn plants was provided by TXVK08, independently of the spray rates used. The most uniform deposits occurred when the spray rates of 200 L ha(-1) was used. Spray deposits were most uniform in B. plantaginea compared to E. heterophylla when both weds were located at crop row, independently of nozzle or spray rates. However, the DG 11002VS spray nozzle provided the most uniform drop deposition on B. plantaginea located between the rows, while the most efficient deposition over E. heterophylla located between rows was TXVK08.

Attraction of the sand fly Nyssomyia neivai (Diptera: Psychodidae) to chemical compounds in a wind tunnel

Background: Similar to other hematophagous insects, male and female sand flies must feed on plants to obtain sugar and, subsequently, energy to complete their life cycles. A large number of compounds emitted by plants may act as volatile signals to these insects. Primary alcohols have been detected in some plants, but in small amounts. In a previous report, the attractiveness of saturated primary alcohols with 7 to 9 carbons was evaluated for Lutzomyia longipalpis, the vector of American visceral leishmaniasis, with positive results.Methods: In the present study, a wide range of primary alcohols, 3 to 10 carbons, were tested to investigate their attractiveness to another sand fly species, Nyssomyia neivai, a putative vector of American cutaneous leishmaniasis. The mixture of compounds that induced the best sand fly response was also evaluated.Results: Of the eight compounds evaluated, hexanol and octanol elicited the best attractive responses for sand fly females.Conclusion: Phytochemicals may be an interesting source of search for new sand fly attractants.

Weed suppression in the formation of brachiarias under three sowing methods

The success of conservation systems such as no-till depends on adequate soil cover throughout the year, which is possible through the use of cover crops. For this purpose the species belonging to the genus Urochloa has stood out by virtue of its hardiness and tolerance to drought. Aiming ground cover for the no-till system, the objective was to evaluate the establishment of two species of the genus Urochloa, in three sowing methods, in the weed suppression and the sensitivity of these forages to glyphosate. The study design was a randomized block with a 2 x 3 x 3 factorial arrangement, in which factor A was composed of Urochloa ruziziensis and Urochloa hybrid CIAT 36087 cv. Mulato II, factor B was formed by sowing methods: sown without embedding, sown with light embedding and sown in rows, and factor C was composed of three doses of glyphosate (0.975, 1.625 and 2.275 kg ha(-1) of acid equivalent). For determination of weed suppression, assessment of biomass yield and soil cover was performed, by brachiaria and weeds, at 30, 60, 90, 120 and 258 days after sowing. Visual assessment of the desiccation efficiency at 7 and 14 days after herbicide application was performed. It is concluded that embedding Urochloa seeds stands out in relation to sowing in the soil surface. Urochloa ruziziensis is more efficient in the dry weight yield, weed suppression, in addition to being more sensitive to glyphosate herbicide.

Raising of horn fly haematobia irritans (L.) (diptera: muscidae) in laboratory by means of egg and larva inoculation

Several studies have required Haematobia irritans (L.) raising in laboratory. The present study assessed two methods of inoculating immature forms of H. irritans to obtain adults. In 2007, 15 Nellore steers (Bos indicus) (L.) were used for the collection of feces free of anthelmintic treatment and flies to produce for eggs and larva. For method I, 30 eggs were incubated in square filter paper (5 × 5 cm) and deposited on bovine feces (500 g) where they were kept until hatching and spontaneous penetration of larvae (L1) into the fecal mass. After 24 h, eggs were analyzed under a stereoscope microscope (40×) for the number of larvae that instinctively penetrated the feces. In method II, larvae were obtained only by natural egg hatching. At birth, 30 larvae were collected and individually inoculated, directly onto the fecal plate by employing a moistened brush. The tests were carried out at controlled temperature (28˚C ± 2˚C) and saturated humidity (80%) until the emergence of flies with both methods. The number of emerged flies was considered in the result. Using method I, 276 (76.7%) flies emerged from 360 inoculated eggs, while using method II, 283 (78.6%) flies emerged from 360 inoculated larvae. There was no significant difference (P = 0.7821) between methods for the number of flies; however, the proportion between males and females by means of larva inoculation was different from 1:1 (P = 0.0146). Results indicated that both methods led to a satisfactory production of flies and egg inoculation provided an easier establishment.

Type of light in sand fly captures (Diptera:Psychodidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)