Emilia Fosbergii Research Articles

Emilia fosbergii Nicolson, a novel and effective accumulator for phytoremediation of mercury-contaminated soils

Soil contamination by toxic metals threatens global public health, highlighting the need for cost-effective and ecologically sound site remediation. In this study, we assessed phytoremediation of Hg-contaminated soils by Emilia fosbergii Nicolson (Asteraceae). Pot experiment was conducted using a substrate of sand and vermiculite (1:1 volume ratio), treatments consisted of five Hg concentrations (0, 1, 3, 5, and 7 mg kg−1). Metal transfer rates were calculated, including accumulation (BAF), translocation (TF) and bioconcentration (BCF) factors. E. fosbergii roots exhibited greater Hg accumulation than other tissues, but biomass production and plant health were not significantly affected at the concentrations tested, as indicated by elongation factors and tolerance index. The results revealed BAF values between 2.18 and 7.14, TF values ranged between 0.15 and 0.52, and the BCF index varied between 8.97 and 26.58. Treatments with Hg content of 5 mg kg−1 and 7 mg kg−1 recorded the highest total Hg concentrations of 66 mg kg−1 and 65.53 mg kg−1 (roots), and 9.18 mg kg−1 and 33.88 mg kg−1 (aerial), respectively. E. fosbergii demonstrated promise for Hg phytoremediation due to its high accumulation capacity, indicated by regular TF and high BCF and BAF indexes, thus classifying it as a high Hg accumulator.

Herbicidal Activity of Smoke Water

Weeds cause more crop yield loss and increase farmers’ production costs more than any other agricultural pest worldwide. Natural extracts can be an important alternative to synthetic herbicides, or they can be one of the resources from which to discover new pesticide leads. The phytotoxic potential of smoke water was evaluated regarding germination and initial growth, prospecting for its possible herbicidal activity in weeds. Herbicidal activity was evaluated through germination, initial growth, and seedling vigor index bioassays in the laboratory and emergency with initial development bioassays in a greenhouse with smoke water solutions at 2.5, 5, 10 and 20% v/v. Experiments with two treatments were analyzed using T-tests for the parametric data and the Mann–Whitney test for the non-parametric data (p < 0.05). Experiments with three treatments or more were analyzed with a one-way ANOVA test followed by a Tukey test for the parametric data and a Kruskal–Wallis test followed by a Dunn test for the non-parametric data (p < 0.05). Linear regression was used to analyze data from the time–injury curve. The greatest effect on germination suppression (98%) was achieved when the Amaranthus viridis seeds were germinated in the laboratory with a 10% smoke water solution. Germination of Raphanus raphanistrum and Digitaria insularis was reduced by 93 and 75%, respectively, at this concentration. In greenhouse experiments, emergence of A. viridis was inhibited 81% by 20% smoke water. In laboratory initial growth experiments, 5% smoke water had the greatest inhibitory effect (94%) on A. viridis. R. raphanistrum initial growth reduction was 82%, Urochloa decumbens was 80%, D. insularis was 77% and Emilia fosbergii was 70% in the same conditions. In greenhouse development experiments, 70% of the A. viridis plants were killed by 5% smoke water treatment. These plants had 88% injury after treatment with 5% smoke water. Therefore, these findings suggest that smoke water solutions have potential as an herbicide, inhibiting the germination and initial growth of monocotyledonous and eudicotyledonous weeds. However, field tests are needed to confirm the potential of smoke water as an herbicide.

Primeiro registro de um ninho de Ceratina (Ceratinula) fioreseana Oliveira (Hymenoptera: Apidae)

ABSTRACT. We provide herein the first report of a nest of Ceratina (Ceratinula) fioreseana Oliveira, 2020, a species that was recently described for the Cerrado domain. The nest was collected in a Passiflora edulis Sims (Passifloraceae) plantation in Minas Gerais State, Brazil and was built in a trap nest, a dry petiole of Cecropia pachystachya Trécul (Urticaceae). Within the nest there was a living female and a brood cell without partition containing a pupa, whose adult female emerged 28 days after pupation. Pollen analysis revealed the dominance of Emilia fosbergii Nicolson (Asteraceae) pollen grains, a weed recorded a few meters from the nest. The record of an adult female within the nest with a pupa and the absence of nest partition might suggest social behavior in this bee species.

A centenary for bacterial spot of tomato and pepper.

Disease symptomsSymptoms include water‐soaked areas surrounded by chlorosis turning into necrotic spots on all aerial parts of plants. On tomato fruits, small, water‐soaked, or slightly raised pale‐green spots with greenish‐white halos are formed, ultimately becoming dark brown and slightly sunken with a scabby or wart‐like surface.Host rangeMain and economically important hosts include different types of tomatoes and peppers. Alternative solanaceous and nonsolanaceous hosts include Datura spp., Hyoscyamus spp., Lycium spp., Nicotiana rustica, Physalis spp., Solanum spp., Amaranthus lividus, Emilia fosbergii, Euphorbia heterophylla, Nicandra physaloides, Physalis pubescens, Sida glomerata, and Solanum americanum.Taxonomic status of the pathogenDomain, Bacteria; phylum, Proteobacteria; class, Gammaproteobacteria; order, Xanthomonadales; family, Xanthomonadaceae; genus, Xanthomonas; species, X. euvesicatoria, X. hortorum, X. vesicatoria.Synonyms (nonpreferred scientific names) Bacterium exitiosum, Bacterium vesicatorium, Phytomonas exitiosa, Phytomonas vesicatoria, Pseudomonas exitiosa, Pseudomonas gardneri, Pseudomonas vesicatoria, Xanthomonas axonopodis pv. vesicatoria, Xanthomonas campestris pv. vesicatoria, Xanthomonas cynarae pv. gardneri, Xanthomonas gardneri, Xanthomonas perforans.Microbiological propertiesColonies are gram‐negative, oxidase‐negative, and catalase‐positive and have oxidative metabolism. Pale‐yellow domed circular colonies of 1–2 mm in diameter grow on general culture media.DistributionThe bacteria are widespread in Africa, Brazil, Canada and the USA, Australia, eastern Europe, and south‐east Asia. Occurrence in western Europe is restricted.Phytosanitary categorizationA2 no. 157, EU Annex designation II/A2.EPPO codesXANTEU, XANTGA, XANTPF, XANTVE.

Pyrrolizidine alkaloids and other constituents from Emilia fosbergii Nicolson

Emilia fosbergii is a member of the tribe Senecioneae (Asteraceae), most species of which contain pyrrolizidine alkaloids. Notwithstanding, the phytochemistry of E. fosbergii is poorly understood, and pyrrolizidine alkaloids produced by this species have yet to be characterized. In this work, the presence of 11 pyrrolizidine alkaloids, three caffeoylquinic acid derivatives, and six flavonoids were detected by liquid chromatography coupled to high-resolution mass spectrometry analyses. Pyrrolizidine alkaloids of otonecine, retronecine, and platynecine bases are annotated in different parts of the plant. Furthermore, emiline was isolated, possibly indicating that E. fosbergii has a close phylogenetic relationship with E. coccinea. The chemophenetic implications of the presence of pyrrolizidine alkaloids in E. fosbergii and tribe Senecioneae are discussed.

Survival of Curtobacterium flaccumfaciens pv. flaccumfaciens in weeds

AbstractWeeds are important alternative hosts of pathogens, responsible for the survival and spread of phytopathogenic bacteria. Our study evaluated the potential of weeds as hosts of Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), causal agent of bacterial wilt, one of the main diseases of common beans. Cff survival was evaluated in the phyllosphere and in the rhizosphere of 21 weeds, in four experiments under field conditions, during the years 2018 and 2019. The aerial part of the plant was inoculated by spraying bacterial suspension (107 cfu/ml) of Cff, while the soil of the growing pots was infested with the same suspension. Cff survival was evaluated every 7 days, for 70 days. The identity of the bacterium was confirmed by PCR with the specific primers CffFOR2 and CffREV4, from strains recovered from all samples. Principal component analysis (PCA) showed that high temperatures and rainfall reduced Cff survival in the phyllosphere, while high temperatures reduced the survival of the bacterium in the rhizosphere. Our results demonstrated that Amaranthus viridis (family Amaranthaceae), Conyza bonariensis, Emilia fosbergii, Galinsoga parviflora, Gnaphalium purpureum (Asteraceae), Raphanus sativus, Lepidium virginicum (Brassicaceae), Commelina benghalensis (Commelinaceae), Ipomoea triloba (Convolvulaceae), Cyperus rotundus (Cyperaceae), Senna obtusifolia (Fabaceae), Digitaria insularis (Poaceae), Nicandra physalodes, and Solanum americanum (Solanaceae) are potential hosts for Cff. Their eradication in common bean fields is recommended, especially in fields with a history of bacterial wilt occurrence.

Weeds as alternate hosts of Xanthomonas euvesicatoria pv. euvesicatoria and X. campestris pv. campestris in vegetable-growing fields in the state of Pernambuco, Brazil

Plant pathogenic Xanthomonas species attack a wide range of agriculture crops and is capable of surviving on weeds. In this study, Xanthomonas strains obtained from weeds grown withing vegetable crop fields in the state of Pernambuco, Northeast Brazil, were identified. Bacterial colonies resembling Xanthomonas were obtained from Aeollanthus suaveolens (strain CCRMXe03), Amaranthus lividus (CCRMXe01 and CCRMXe02), Sida glomerata (CCRMXe04), and Emilia fosbergii (CCRMXe04). All weeds but E. fosbergii exhibited lesions on the leaves. Phylogenetic analysis of the gyrB and rpoD genes and PCR-specific assays allowed to identify X. euvesicatoria pv. euvesicatoria (CCRMXe01, CCRMXe02, CCRMXe03, and CCRMXe04) and X. campestris pv. campestris (CCRMXcc371). All strains but CCRMXe03 were pathogenic to its host of origin. All X. euvesicatoria pv. euvesicatoria strains were pathogenic to leaves and fruits of tomato and bell pepper. Two strains, CCRMXe03 and CCRMXe04, were capable of inducing soft rot in fruits. Amylolytic activity was found in all strains and two strains (CCRMXe03 and CCRMXe04) degraded pectate. Strain CCRMXcc371 was pathogenic to cabbage, kale, cauliflower, and broccoli. This work provides new knowledge of hosts for two important plant pathogenic bacteria for vegetable crops.

Phytochemical Profile and Evaluation of the Allopathic Effect of Three Species of the Genus Cyperus (Cyperaceae)

The genus Cyperus is widely distributed worldwide and occurs in various regions of Brazil. Research has reported the allelopathic potential of species belonging to this genus. From this perspective, the present study analyzes the phytochemical profile and allelopathic effect of seven concentrations of the aqueous extracts of Cyperus distans L., Cyperus laxus Lam., and Cyperus rotundus L. The allelopathic potential was evaluated in triplicate from germination bioassays on seeds of two species, Lactuca sativa L. and Emilia fosbergii Nicolson. In addition, phytochemical analyses were performed to analyze possible allelochemicals present in aqueous extracts of three species by phytochemical screening and high-performance liquid chromatography (HPLC). The evaluated variables were: germination (G) and germination speed index (GSI). The data obtained were submitted to the F test, and regression analysis was performed to compare means. The results showed higher susceptibility of E. fosbergii to aqueous extracts of C. distans, C. laxus, and C. rotundus at all concentrations analyzed (0.94, 1.87, 3.75, 7.5, 15, and 30%). In turn, the germination rate of L. sativa seeds decreased only at the highest concentrations (between 15 and 30%) of the same extracts. This allelopathic potential may be directly associated with the biosynthetization of phenolic compounds by Cyperus spp., analyzed in this study by phytochemical prospecting and HPLC.

Phytochemical Profile and Evaluation of the Allelopathic Effect of the Aqueous Extract of Fimbristylis miliacea (L.) Vahl (Cyperaceae)

The allelopathic potential of some plant species has been scientifically proven over the years. The use of such natural compounds with phytotoxic activity is an alternative to synthetic herbicides. Thus, this research aims to analyze the phytochemical profile and the allelopathic effect of aqueous extracts of Fimbristylis miliacea (L.) Vahl. The allelopathic potential was evaluated by germination bioassays using seeds from two receptor species (Lactuca sativa L. and Emilia fosbergii Nicolson) and seven concentrations of aqueous extracts of F. miliacea aerial and underground parts in triplicate. The variables evaluated were germination (G) and germination speed index (GSI). The data obtained were submitted to F test and the averages to regression analysis. In addition, phytochemical analyses were performed to analyze possible allelochemicals present in aqueous extracts of F. miliacea through phytochemical screening and by high performance liquid chromatography (HPLC). The aqueous extracts of aerial and underground parts of F. miliacea inhibit the germination of E. fosbergii seeds at all concentrations analyzed (0.94, 1.87, 3.75, 7.5, 15 and 30%). However, the same extracts do not show any effects when evaluated in L. sativa seeds. The aqueous extract of F. miliacea shows important chemical constituents (gallic acid, chlorogenic acid, rutin, luteolin, apigenin, acacetin, and alkaloids) that can be directly related to the allelopathic effects observed in E. fosbergii seeds.

Cargas polínicas en entomofauna visitante floral de <i>Persea americana</i> (Lauraceae) cv. Hass

El análisis de las cargas de polen de los insectos visitantes florales del aguacate Hass es un método que permite determinar la importancia de estas especies en planes de manejo de la polinización del cultivo y elucidar el uso de hábitat e importancia de la flora en el sostenimiento de estas especies. El objetivo de este estudio fue identificar mediante un análisis polínico en los insectos visitantes florales las especies vegetales que visitan con mayor frecuencia. El estudio se realizó en dos huertos de Morales (Cauca, Colombia), durante dos periodos de floración. Se recolectaron manualmente los insectos visitantes florales y se obtuvieron muestras del polen en sus cuerpos. Se extrajo la carga polínica de las cinco especies más frecuentes durante el muestreo. El análisis palinológico mostró que los visitantes florales no limitan su visita a un recurso específico como el polen de aguacate Hass, sino que utilizan diferentes especies en el agroecosistema y sus alrededores. Los insectos transportan polen de 18 familias botánicas, siendo las plantas Bidens pilosa, Tridax procumbens, Emilia fosbergii, Brachiaria sp., y Mikania sp. importantes como flora polinífera. El estudio revela la importancia de preservar la diversidad de especies que, con su carga polínica, garanticen la óptima polinización de las flores.

ASSOCIATION OF INDAZIFLAM AND OXYFLUORFEN IN COFFEE PRE- TRANSPLANTATION

Weed management in the pre-transplantation of coffee plants is an essential condition for the future success of the crop. Currently, the producer has few options to perform chemical management at this stage. Therefore, one of the solutions that is being used is the tank mixing of products proven efficient with new products on the market, such as indaziflam. The objective of this study is to know the selectivity of indaziflam, associated or not with oxyfluorfen, in coffee pre-planting and its effectiveness in weed control. Thus, the following treatments were tested in the field: indaziflam (25 g ha<sup>-1</sup> a.i.), indaziflam (50 g ha<sup>-1</sup> a.i.), oxyfluorfen (960 g ha<sup>-1</sup> a.i.), indaziflam (25 g ha<sup>-1</sup> a.i.) + oxyfluorfen (960 g ha<sup>-1</sup> a.i.), indaziflam (50 g ha<sup>-1</sup> a.i.) + oxyfluorfen (960 g ha<sup>-1</sup> a.i.), plus a weeded and a non-weeded control. All treatments caused low intoxication in the seedlings, but without impairing the development and orphological variables of the plants. The treatments were efficient in controlling the species <em>Bidens pilosa L</em>., <em>Commelina benghalensis</em> L., <em>Urochloa decumbens</em>, <em>Emilia fosbergii</em> and <em>Melampodium perfoliatum</em> until 68 days after application. At 104 days, it was observed that there was a reduction in the efficiency of the products. It is concluded that the associated use of indaziflam and oxyfluorfen does not cause intoxications capable of interfering with the development of coffee plants. The association of these herbicides or their isolated applications is efficient in the control of weeds in the pre-transplantation of coffee plants, and the choice of the best management strategy is dependent on the weed community present in each area.

Health-Promoting Properties of Brazilian Unconventional Food Plants

This study lies on the unexplored and unprecedented opportunities for the discovery of Unconventional Food Plants (UFPs) rich in nutrients and bioactive compounds. UFPs grow spontaneously and have been consider an important food sources and demonstrate health-promoting properties. This study aimed to investigate the phytochemical profiles together with the anti-inflammatory and antioxidant in vitro activities of the Brazilian UFPs Hypochaeris chillensis, Emilia fosbergii and Emilia sonchifolia. Preliminary secondary metabolites were identified by LC–MS/MS analysis. Antioxidant activity was determined by the ABTS cation radical scavenging capacity, ferric reducing/antioxidant potential (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. The effects of UFPs on nitric oxide (NO), superoxide anion generation (O2•−), and pro-inflammatory cytokine (TNF-α and IL-6) production and on nuclear factor kappa B (NF-κB) activity was determined using Griess reagent, immunoenzymatic assay kits (ELISA) and chemiluminescence measurements in cell-based assays, respectively. Phytochemical analysis revealed significant amount of total phenolic content in all of the studied plants. E. fosbergii showed the highest antioxidant capacity in all of the chemical assays, exhibiting IC50 values of 32.9 ± 4.8, 50.2 ± 2.3 and 24.0 ± 2.9 µg mL−1 in the ABTS, DPPH and FRAP assays, respectively. The studied UFPs showed a significant intracellular reduction in NO and O2•− production in LPS-stimulated RAW 264.7 macrophages. Additionally, UFPs suppressed the production of the pro-inflammatory cytokines TNF-α and IL-6 in a dose-dependent manner. Moreover, E. sonchifolia suppressed NF-κB activity. Altogether, the investigated UFPs exhibited promising bioactive compounds that were capable of neutralizing free radicals, controlling oxidative stress and modulating the inflammatory process.

Evaluación de arvenses como hospedantes alternos de nematodos fitoparásitos en cafetales en Costa Rica

There is potential for weeds to be alternative hosts of plant-parasitic nematodes (PPN), but a methodology that assesses the phytosanitary risk derived from the presence of weeds in plantations is not available. This research was conducted in order to determine if the presence of weeds in coffee plantations (organic and conventional) represented a phytosanitary risk due to their role as alternative hosts of PPN. The research was developed into two plantation located in Aserrí, San José, Costa Rica during August, 2010. The most important weeds were identified in the plantations, also nematodes of the genera Meloidogyne, Pratylenchus and Helicotylenchus were quantified in soil and roots from selected weeds and coffee plants. A permutational analysis of variance was executed in order to determine the genera of PPN that significantly differed from the ones found in weeds to the ones found in coffee plants. Based on these results, the weeds were classified as: reservoir, trap crop, or weak host of PPN. This classification criterion, in addition to life cycle and type of parasitism of the PPN were used to assign numerical values to the weeds. The values were used to calculate the Phytosanitary Risk Index (PRI) that acquired a maximum value of 10 for the weed Piper umbellatum in the organic plantation, and a maximum value of 24 for Commelina diffusa, Emilia fosbergii, Spananthe paniculata, Delilia biflora, and Spermacoce hirta in the conventional plantation. The results indicated that from a nematological perspective the presence of these weeds in coffee plantation could be a potential risk for coffee plants

DISTRIBUTION OF Meloidogyne enterolobii IN GUAVA ORCHARDS IN THE STATE OF CEARÁ, BRAZIL

ABSTRACT Among the factors negatively impacting guava (Psidium guajava) crop in Brazil, one of the most important is the root-knot nematode, Meloidogyne enterolobii, which may cause considerable yield losses and even the cessation of guava cultivation in some areas. In addition to affecting guava, the pathogen has been reported as a parasite in various other crops, among them both oleraceous and ornamental crops, as well as in spontaneous vegetation. The aim of this study was to verify the occurrence of M. enterolobii in plants collected in guava orchards in different counties of Ceará state, identified through electrophoresis with the isoenzyme esterase, and to observe its infecting behavior into Meloidogyne differentiating plants. Fifty root samples from guava, tasselflower (Emilia fosbergii), and jurubeba (Solanum paniculatum), were collected in 13 counties from eight micro-regions in the state of Ceará. In all analyzed samples, only esterase phenotype M2 (Rm: 0.6; 0.9), characteristic of M. enterolobii, was detected, showing that the nematode is widespread in orchards throughout the state, where is affecting these fruit tree, and that it is also able to parasitizing plants of the spontaneous vegetation. Based on the results, this nematode currently constitutes a serious threat to guava plantations in Ceará, and effective control mechanisms are crucial to prevent the spread of this pathogen to other, still unaffected, areas.

Do floral resources in Eucalyptus plantations affect fitness parameters of the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)?

Adult parasitoids depend on sugar-rich foods such as nectar and honeydew to meet their energy requirements. The availability of nectar, honeydew or fruit sap affects the longevity, fecundity and dispersal of parasitoids and consequently their potential as biocontrol agents. The aim of this study was to evaluate the development and reproduction of an important parasitoid of Brazilian ecosystems, Palmistichus elaeisis (Delvare and LaSalle 1993) (Hymenoptera: Eulophidae), fed with nectar from Eucalyptus flowers and flowering herbs. Males and females of this parasitoid were individualized in glass tubes, and their survival and longevity were evaluated in the following treatments: flowers of Bidens pilosa L. 1753, Emilia fosbergii Nicolson 1975, Galinsoga parviflora Cav. 1796, Sonchus oleraceus L. 1753, Taraxacum officinale F.H. Wigg. 1780 (Asteraceae) and Eucalyptus sp. (Myrtaceae), a honey droplet or no food. In the second trial, six P. elaeisis females were placed into plastic pots containing one Tenebrio molitor L. 1758 (Coleoptera: Tenebrionidae) host pupa under the same treatments. Parasitism and emergence, the duration of the egg–adult period, the number of adults per pupa, the sex ratio, the width of the head capsule and the body length of P. elaeisis were evaluated. Food sources of honey or flowering herbs increased the survival, longevity, period of parasitism, percentage of parasitized pupae and number of progeny of P. elaeisis. Longevity and reproduction were seriously compromised in the absence of sugar feeding.

Evaluating Weeds as Hosts of Tomato yellow leaf curl virus.

Bemisia tabaci (Gennadius) biotype B transmits Tomato yellow leaf curl virus (TYLCV), which affects tomato production globally. Prompt destruction of virus reservoirs is a key component of virus management. Identification of weed hosts of TYLCV will be useful for reducing such reservoirs. The status of weeds as alternate hosts of TYLCV in Florida remains unclear. In greenhouse studies, B. tabaci adults from a colony reared on TYLCV-infected tomato were established in cages containing one of four weeds common to horticultural fields in central and south Florida. Cages containing tomato and cotton were also infested with viruliferous whiteflies as a positive control and negative control, respectively. Whitefly adults and plant tissue were tested periodically over 10 wk for the presence of TYLCV using PCR. After 10 wk, virus-susceptible tomato plants were placed in each cage to determine if whiteflies descended from the original adults were still infective. Results indicate that Bidens alba, Emilia fosbergii, and Raphanus raphanistrum are not hosts of TYLCV, and that Amaranthus retroflexus is a host.

Densities of Eggs and Nymphs and Percent Parasitism of Bemisia tabaci (Hemiptera: Aleyrodidae) on Common Weeds in West Central Florida.

The density of eggs and nymphs of Bemisia tabaci (Gennadius) biotype B and the percent parasitism of the nymphs were measured from specimens collected on nine species of weeds, commonly found in west central Florida during the spring and summer of 2012 and 2013. The weeds were direct seeded in 2012 and grown as transplants in 2013 for Randomized Complete Block design experiments. The leaf area of each whole-plant sample was measured and the B. tabaci density parameters were converted to numbers per 100 cm2. In June and July, 2013, whole-plant samples became too large to examine entirely, thus a representative portion of a plant totaling about 1000 cm2 was sampled. Egg and nymph densities and percent parasitism varied greatly among weed species, and were higher overall in 2012 than in 2013. The highest densities of eggs and nymphs were measured on Abutilon theophrasti, Cassia obtusifolia and Emilia fosbergii each year. Lower densities of immature B. tabaci were measured on most dates for Amaranthus retroflexus, Bidens alba, Ipomoea lacunosa, Sesbania exaltata and Sida acuta. Nymph to egg ratios of 1:4 were observed on A. theophrasti and S. exaltata in 2012, while less than one nymph per ten eggs was observed overall on A. retroflexus, E. fosbergii and I. lacunosa. In 2012, parasitism rates of 32.3% were measured for B. alba, 23.4% for C. obtusifolia and 17.5% for S. acuta. Of the 206 parasitoids reared out over two seasons, 96.6% were Encarsia spp. and the remainder Eretmocerus spp. The role of weeds in managing B. tabaci is discussed.

Crescimento do pinhão-manso em competição com plantas daninhas em dois tipos de solo

We aimed with this study to evaluate the effect of six weed species grown in competition with plants of jatropha (Jatropha curcas L.) in Red Yelow Oxisol (LVA) and Quartizarenic Neossol (NQ). The experiment was installed in randomized blocks design with four replications. The treatments were arranged in a 2x6 factorial design, with the first factor represented by two soil types (LVA and NQ) and six weed species (Ageratum conyzoides L., Bidens pilosa L., Cenchrus echinatus L., Commelina benghalensis L., Emilia fosbergii N.) grown along with the crop, plus a control with no competition. Presence of weeds negatively affected growth of jatropha both in LVA and NQ. Among the studied species, C. echinatus and E. fosbergii promoted greater negative effect on jatropha, for most of the variables tested. J. curcas showed better tolerance to reductions in shoot dry matter accumulation when in competition under LVA, a situation contrary to the root system when this oil crop was grown in NQ.soil The growth of jatropha is affected by competition with weeds, but the magnitude of this effect is dependent on the weed species and type of soi

Avaliação de herbicidas aplicados em pós-emergência sobre e sob a palha em cana crua e o destino ambiental

O objetivo deste trabalho foi avaliar a eficiência de vários herbicidas isolados ou associados, aplicados em pós-emergência, na cultura da cana-soca, colhida mecanicamente no sistema cana crua, procurando evidenciar diferenças no seu desempenho quando aplicados sobre ou sob a palha, bem como, ainda dentro do conceito de sustentabilidade e avaliação de risco ambiental, quantificar os comportamentos nos quais esses produtos apresentam maior risco. O experimento foi conduzido no município de Bariri-SP, em áreas da Usina Della Colletta, Fazenda Santo Antonio, em área de cana-soca (cultivar RB 72 754) colhida mecanicamente. Foi utilizada a cana-soca de quarto corte, plantada no espaçamento de 1,40 m, em solo Argiloso Vermelho-Amarelo com 5% de declive. Empregou-se o delineamento experimental de blocos ao acaso com 14 tratamentos (trifloxysulfuron-sodium+ametrina 720 e 960; mesotrione 182 e 292,6; mesotrione+ametrina 292,6+1.500; mesotrione+trifloxysulfuron-sodium 182,8+720; metribuzin 2.680; trifloxysulfuron-sodium+ametrina + hexazinone+diuron 720+900; amicarbazone 45; hexazinone+diuron 1.320; trifloxysulfuron-sodium+sulfentrazone 720+700 (todos em gramas de ingrediente ativo); testemunha; testemunha capinada) e quatro repetições, para cada tipo de aplicação (sobre e sob a palha) disposta lado a lado. As avaliações realizadas foram: fitotoxicidade aparente, altura, estande, eficiência no controle da Digitaria horizontalis, Cenchrus echinatus, Emilia fosbergii e Sida cordifolia, números de internódios e o primeiro internódio. O modelo matemático foi o nível I de fugacidade, utilizando os compartimentos ar, água, solo, sedimento, biota, raiz, caule e folha. Os resultados mostraram que os herbicidas trifloxysulfuron + diuron, mesotrione, metribuzin, ametrina, hexazinone + diuron, amicarbazone e sulfentrazone isolados ou associados, aplicados em pós-emergência, em área total da cultura da cana-de-açúcar, foram altamente eficientes no controle das principais plantas daninhas presentes. A aplicação desses herbicidas sobre ou sob a palhada da cana crua não mostrou diferença na eficiência de controle ou sobre os demais parâmetros avaliados. A aplicação do modelo de fugacidade objetivando avaliar o comportamento preferencial mostrou que todos os herbicidas tendem a ter maior distribuição no compartimento água.

Host range of Secusio extensa (Lepidoptera: Arctiidae), and potential for biological control of Senecio madagascariensis (Asteraceae)

Secusio extensa (Lepidoptera: Arctiidae) was evaluated as a potential biological control agent for Madagascar fireweed, Senecio madagascariensis (Asteraceae), which has invaded over 400 000 acres of rangeland in the Hawaiian Islands and is toxic to cattle and horses. The moth was introduced from southeastern Madagascar into containment facilities in Hawaii, and host specificity tests were conducted on 71 endemic and naturalized species (52 genera) in 12 tribes of Asteraceae and 17 species of non-Asteraceae including six native shrubs and trees considered key components of Hawaiian ecosystems. No-choice feeding tests indicated that plant species of the tribe Senecioneae were suitable hosts with first instars completing development to adult stage on S. madagascariensis (78.3%), Delairea odorata (66.1%), Senecio vulgaris (57.1%), Crassocephalum crepidioides (41.2%), and at significantly lower rates on Emilia fosbergii (1.8%) and Erechtites hieracifolia (1.3%). A low rate of complete larval development also was observed on sunflower, Helianthus annuus (11.6%), in the tribe Heliantheae. However, sunflower was rejected as a potential host in larval-feeding and adult oviposition choice tests involving the primary host S. madagascariensis as control. Although larvae died as first instars on most test species, incomplete development and low levels of feeding were observed on nine species in the tribes Heliantheae, Cardueae and Lactuceae. Larvae did not feed on any non-Asteraceae tested, including species with similar pyrrolizidene alkaloid chemistry, crops, and six ecologically prominent native species. Because all species of Senecioneae are non-native and weedy in Hawaii, these results indicate that S. extensa is sufficiently host-specific for introduction for biological control. High levels of feeding damage observed on potted plants indicate that S. extensa can severely impact the target fireweed as well as D. odorata, a noxious weed in native Hawaiian forests.