Short-term Response of Holcus lanatus L. (Common Velvetgrass) to Chemical and Manual Control at Yosemite National Park, USA

One of the highest priority invasive species at both Yosemite and Sequoia and Kings Canyon national parks is Holcus lanatus L. (common velvetgrass), a perennial bunchgrass that invades mid-elevation montane meadows. Despite velvetgrass being a high priority species, there is little information available on control techniques. The goal of this project was to evaluate the short-term response of a single application of common chemical and manual velvetgrass control techniques. The study was conducted at three montane sites in Yosemite National Park. Glyphosate spotspray treatments were applied at 0.5, 1.0, 1.5, and 2.0% concentrations, and compared with hand pulling to evaluate effects on cover of common velvetgrass, cover of other plant species, and community species richness. Posttreatment year 1 cover of common velvetgrass was 12.1% 6 1.6 in control plots, 6.3% 6 1.5 averaged over the four chemical treatments (all chemical treatments performed similarly), and 13.6% 6 1.7 for handpulled plots. This represents an approximately 50% reduction in common velvetgrass cover in chemically- treated plots recoded posttreatment year 1 and no statistically significant reduction in hand pulled plots compared with controls. However, there was no treatment effect in posttreatment year 2, and all herbicide application rates performed similarly. In addition, there were no significant treatment effects on nontarget species or species richness. These results suggest that for this level of infestation and habitat type, (1) one year of hand pulling is not an effective control method and (2) glyphosate provides some level of control in the short-term without impact to nontarget plant species, but the effect is temporary as a single year of glyphosate treatment is ineffective over a twoyear period

Arsenite efflux is not enhanced in the arsenate-tolerant phenotype of Holcus lanatus

P>Arsenate tolerance in Holcus lanatus is achieved mainly through suppressed arsenate uptake. We recently showed that plant roots can rapidly efflux arsenite to the external medium. Here, we tested whether arsenite efflux is a component of the adaptive arsenate tolerance in H. lanatus. Tolerant and nontolerant phenotypes were exposed to different arsenate concentrations with or without phosphate for 24 h, and arsenic (As) speciation was determined in nutrient solutions, roots and xylem sap. At the same arsenate exposure concentration, the nontolerant phenotype took up more arsenate and effluxed more arsenite than the tolerant phenotype. However, arsenite efflux was proportional to arsenate uptake and was not enhanced in the tolerant phenotype. Within 2-24 h, most (80-100%) of the arsenate taken up was effluxed to the medium as arsenite. About 86-95% of the As in the roots and majority of the As in xylem sap (c. 66%) was present as arsenite, and there were no significant differences between phenotypes. Arsenite efflux is not adaptively enhanced in the tolerant phenotype H. lanatus, but it could be a basal tolerance mechanism to greatly decrease cellular As burden in both phenotypes. Tolerant and nontolerant phenotypes had a similar capacity to reduce arsenate in roots. New Phytologist (2009) 183: 340-348doi: 10.1111/j.1469-8137.2009.02841.x

Novedades nomenclaturales en el género "Holcus" (Poaceae).

Nomenclatural novelties in the genus Holcus (Poaceae)Palabras clave. Nomenclatura, Holcus, Poaceae.Key words. Nomenclature, Holcus, Poaceae

Modelo espacial de distribuição da lagarta-da-pastagem (Pseudaletia unipuncta, Haworth) (Lepidoptera: Noctuidae) na ilha Terceira

Mestrado em Engenharia Agronómica.A lagarta-da-pastagem (Pseudaletia unipuncta, Haworth) é considerada uma das pragas mais prejudiciais das pastagens, e que os agricultores mais temem, pois sendo uma praga polífaga pode também afetar outras culturas quando a sua densidade larvar é muito elevada e a sua cultura preferencial tiver sido já consumida. O seu combate é muito difícil, dado que a lagarta só é visível pelos agricultores quando atinge os últimos ínstares larvares, sendo estes os mais prejudiciais. Existem diversos produtos químicos aplicáveis no combate à lagarta-da-pastagem, de entre eles os mais eficazes são os à base de deltametrina e lambda-cialotrina. Também a luta biológica é um dos métodos de combate mais utilizados, em que os parasitóides com mais eficácia é o Apanteles militaris (Walsh). A aplicação de produtos à base de Bacillus thurigiensis (Berliner) também regista bons resultados. Um outro método eficaz e que não implica custos e desprovido de qualquer tipo de impacte ambiental nas pastagens é a adoção de meios de luta culturais, possibilitando eliminar ou prevenir o aparecimento e a instalação da lagarta tais como o maneio adequado da pastagem impedindo assim a formação de grandes populações de P. unipuncta e possibilitando uma definição atempada da frequência do pastoreio, da altura de corte e do apascentamento adequado. Neste estudo procurou-se quantificar, em campo, a densidade larvar de Pseudaletia unipuncta (Haw.) analisando as capturas de adultos nas armadilhas colocadas nas pastagens e posteriormente foi-se relacionar estes dados com os fatores climáticos, temperatura, humidade relativa e precipitação e com o tipo de coberto vegetal existente a fim concluirmos em que altitudes, tipos de pastagens e altura do ano é que esta praga se encontra em maior densidade populacional atendendo ao tipo de cobertura existente. Este estudo foi realizado no ano de 2011 entre os meses de Maio e Novembro e foram escolhidas dez pastagens a diferentes altitudes em redor de toda a ilha. Em cada parcela foi colocada uma armadilha do tipo funil para a captura de adultos de Pseudaletia unipuncta Haw. e semanalmente era feita a prospeção larvar no terreno. Foi feito o levantamento da composição de espécies vegetais presentes em cada pastagem. Podemos concluir através dos resultados obtidos que na parcela Pico Catarina Vieira existe uma dominância de espécie vegetal, Holcus lanatus L., coincidindo com o local onde se capturou uma maior quantidade de larvas, havendo uma correlação muito elevada entre a densidade da lagarta-da-pastagem com a dominância da vegetação. O clima também tem uma grande influência na densidade larvar, a lagarta desenvolve-se melhor em sítios amenos, com bons valores de humidade relativa e precipitação. Por fim, a altura do ano em que se obteve maiores capturas de Pseudaletia unipuncta Haw. foi no mês de Agosto.ABSTRACT: The armyworm (Pseudaletia unipuncta, Haworth) is considered one of the most damaging pests of pastures, and farmers fear most, because being a polyphagous pest can also affect other crops when their larval density is very high and it’s preferential culture has already been consumed. It’s a very difficult pest to combat, because farmers can only see the armyworm when it reaches the last larval states, which are the most damaging. There are many chemical products applicable in the armyworm combat, among them the most effective are those the basis is made of deltamethrin and lambda-cyhalothrin. Also the biological control is one of the most methods used in this pest prevention, wherein the more effectively parasites is Apanteles militaris (Walsh). The application of products based on Bacillus thuringiensis (Berliner) also records good results. Another method effective and that does not involve any costs and devoid of any environmental impact in pastures is the adoption of cultural methods, making it possible to eliminate or prevent the onset and installation of the armyworm, such as a proper management. This helps preventing the formation of large populations of P. unipuncta and enabling an early definition of the frequency of grazing, cutting height and adequate grazing. This study sought to quantify in the field, the density of larval Pseudaletia unipuncta (Haw.) analyzing the catches of adults in traps placed in pastures and then relate these data with climatic factors, temperature, relative humidity and rainfall and with the type of existing vegetation to conclude that altitude pasture types and time of year is that this pest is found in higher population density given the type of existing coverage. This study was accomplished in 2011 between the months of May and November, and were chosen ten pastures at different altitudes around the entire island. In each plot was placed a trap for capturing Pseudaletia unipuncta Haw. adults and were made weekly larval exploration. Afterwards was the survey made of the composition of plant species present in each pasture. We concluded that the results obtained in the parcel Pico Catarina Vieira show us that there was a dominance of plant species, Holcus lanatus L., coinciding with the location where were captured a greater amount of larvae, showing a very high correlation between the density of the caterpillar with the dominant vegetation. The climate also has a great influence on larval density, the caterpillar develops better in locations were the weather is more pleasant, with good values of relative humidity and precipitation. Finally, the time of year that showed higher catches Pseudaletia unipuncta Haw. was in August

Variability in Tolerance to Water Stress by \u3cem\u3eHolcus Lanatus\u3c/em\u3e L., \u3cem\u3eBromus Valdivianus\u3c/em\u3e Phil. and \u3cem\u3eAgrostis Capillaris\u3c/em\u3e L. Accessions

Holcus lanatus L. (Hl), Bromus valdivianus Phil. (Bv) and Agrostis capillaris L. (Ac) are frequently present in the naturalised pasture of the Chilean humid region, which has a summer drought with two distinguishable areas according to average summer rainfall: a Northern area (Long summer drought, LSuD: 136-186 mm;) and a Southern area (Short summer drought, SSuD: 186-338 mm). It was hypothesised that plant species have colonised areas with different water deficits during summer through differentiated drought tolerance, which would imply ecotype generation

Emergência E Estabelecimento De Espécies Nativas E Exóticas Em Solos De Campos Convertidos E Nativos Remanescentes Do Planalto - Sul Do Brasil

Native grasslands in the Campos de Cima da Serra, Brazil, are being converted at speed for exotic tree plantations and cropland. The impact of modified and novel soil conditions on the establishment of native grassland species is unknown; establishment of non-native species, deliberately or accidentally introduced, could be favoured. In a common garden composed of fully randomized replicate samples of soils collected from remnant grassland, former cropland and pine plantations, we tested emergence and establishment of five cold-season species: Native low-tussock grass Piptochaetium montevidense (Spreng.) Parodi; native legume Trifolium riograndense Burkart; naturalized low-tussock grass Vulpia bromoides (L.) Gray; low-tussock grass Holcus lanatus L., cultivated and naturalized in Brazil; and a cultivar of non-native Trifolium repens. Other than expected, soil type and species*soil type interactions had no significant effect on seedling emergence after 132 days in the field. Species effect on seedling emergence, however, was highly significant. Vulpia bromoides emergence was significantly highest in all soil types. Holcus lanatus and Trifolium riograndense both achieved second highest emergence rates and did not differ significantly from each other. Lowest overall emergence rates were found in the non-native clover cultivar. Lab germination tests failed for Piptochaetium, although it showed reasonable emergence in the field. Good performance of the native clover is encouraging for future grassland restoration, but the value of highly germinable Vulpia as a forage remains to be tested. Holcus tolerates a wide range of soil conditions and its life history traits may promote naturalization, or even invasiveness. Native grasslands of the region should be monitored for this species. Studies like these, but set up on a larger geographical scale and with a wider array of native species, will be essential in developing ecological restoration methods for southern Brazilian grasslands. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17

Effect of arsenic-phosphorus interaction on arsenic-induced oxidative stress in chickpea plants

Arsenic-induced oxidative stress in chickpea was investigated under glasshouse conditions in response to application of arsenic and phosphorus. Three levels of arsenic (0, 30 and 60 mg kg−1) and four levels of P (50, 100, 200, and 400 mg kg−1) were applied to soil-grown plants. Increasing levels of both arsenic and P significantly increased arsenic concentrations in the plants. Shoot growth was reduced with increased arsenic supply regardless of applied P levels. Applied arsenic induced oxidative stress in the plants, and the concentrations of H2O2 and lipid peroxidation were increased. Activity of superoxide dismutase (SOD) and concentrations of non-enzymatic antioxidants decreased in these plants, but activities of catalase (CAT) and ascorbate peroxidase (APX) were significantly increased under arsenic phytotoxicity. Increased supply of P decreased activities of CAT and APX, and decreased concentrations of non-enzymatic antioxidants, but the high-P plants had lowered lipid peroxidation. It can be concluded that P increased uptake of arsenic from the soil, probably by making it more available, but although plant growth was inhibited by arsenic the P may have partially protected the membranes from arsenic-induced oxidative stress

Flora of Đurđevački pijesci

Botaničko-geografski rezervat „Đurđevački pijesci“ nalaze se između Đurđevca i Kalinovca, a zauzima 19,5 ha. U rezervatu su provedena terenska istraživanja tijekom 2016. i 2017. godine, te je zabilježeno 126 svojti među kojima su najzastupljenije porodice Poaceae, Asteraceae, Caryophyllaceae, Cichoriaceae, Rosaceae i Fabaceae. Analizom životnih oblika utvrđeno je da dominiraju hemikriptofiti, no visoki udio imaju i fanerofiti, što ukazuje da je rezervat u procesu sukcesije. Osim spektra životnih oblika na potiskivanje pješčarske vegetacije ukazuju, preko ekoloških indeksa, i promjena pH i vlažnosti tla što dovodi do naseljavanja korovnih, invazivnih i nepješčasrkih vrsta. Da bi se spriječilo potiskivanje pješčarske vegetacije potrebne su hitne mjere zaštite za očuvanjem rezervata.The Special Geographical and Botanical Reserve „Đurđevački pijesci“ (Sands of Đurđevac), with an area of 19.5 ha, is situated between the towns of Đurđevac and Kalinovac. Through field research conducted in the reserve during 2016 and 2017, 126 taxa were recorded, with the families Poaceae, Asteraceae, Caryophyllaceae, Cichoriaceae, Rosaceae and Fabaceae being the most prevalent. The life forms analyses showed that hemicryptophytes are dominant, but that phanerophytes are also significantly present, which indicates that the reserve is experiencing vegetation succession. Along with spectar of life forms, the disappearance of sand vegetation is is visible through ecological indices. This is evident through the change in the soil reaction (pH value) and soil moisture, which leads to colonization by weed, invasive and non-psamophytic taxa. Immediate protection measures are required to stop the suppression of sand vegetation, and preserve the Botanical Reserve

A comparative study of herbage intake, ingestive behaviour and diet selection, and effects of condensed tannins upon body and wool growth in lambs grazing Yorkshire fog (Holcus lanatus) and annual ryegrass (Lolium multiflorum) dominant swards

An experiment was carried out from August to early November 1994 to examine differences in diet selection, herbage intake, grazing behaviour and animal performance between weaned lambs rotationally grazing swards of annual ryegrass (Lolium multiflorum)/white clover (Trifolium repens) and Yorkshire fog (Holcus lanatus)/T. repens with or without Lotus corniculatus. There were four replicate groups of six lambs per treatment. The effects of condensed tannins (CT) on lamb production were assessed by twice-daily oral administration of 10g polyethylene glycol (PEG; molecular weight 4000) to half the lambs on each sward. The Lotus content of all swards was very low, and results are presented here for main sward comparisons meaned over lotus treatments. Overall mean estimates of pre-grazing herbage mass and sward surface height for the annual ryegrass and Yorkshire fog swards respectively, were 5820 v. 4360 +/- 190 kg DM/ha (P , P < 0.01) and liveweight gain (141 v. 120 +/- 4.3 g per lamb per day, P < 0.01), although differences in carcass weight (17.9 v. 18.2 +/- 0.3 kg) and FEC transformed values (9.6 v. 11.0 +/- 06 eggs/g fresh faeces) were not significant. The effects of CT on animal performance were greater in Yorkshire fog swards. CT had no significant effects on diet selection, herbage intake and grazing behaviour patterns