CONTROL OF GLYPHOSATE RESISTANT HAIRY FLEABANE (Conyza bonariensis) WITH DICAMBA AND 2,4-D

Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-response curves, of glyphosate, 2,4-D, isolated dicamba and glyphosate-dicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 ga.i. ha(-1) for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a. e. ha(-1). The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a. e. ha(-1). Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a. e. ha(-1) rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.

Morfologia e topografia do fígado e pâncreas de emas Rhea americana

As emas são aves ratitas nativas do continente sul americano, são consideradas aves primitivas do ponto de vista filogenético que constituem um grupo altamente especializado. Este estudo buscou caracterizar macro e microscopicamente o fígado e pâncreas de emas. O material foi coletado no Centro de Multiplicação de Animais Silvestres (CEMAS), na cidade de Mossoró-RN, Brasil, (Registro IBAMA n° 14.78912). Utilizaram-se 20 animais jovens com idade entre dois e seis meses independente do sexo. Em emas, o fígado se relacionava cranialmente com o ápice do coração, dorsalmente com os pulmões, esôfago e o proventrículo gástrico, caudalmente, com o ventrículo gástrico, o baço, o duodeno e parte do jejuno. Apresentava coloração vermelha escura e possuía apenas dois lobos, sendo o direito ligeiramente menor que o esquerdo. Histologicamente, era revestido por uma cápsula de tecido conjuntivo delgada e cada lóbulo hepático pôde ser identificado pela presença evidente de veias centrais, com muitos sinusoides comunicando-se com elas. O pâncreas, ventralmente, apresentava-se como uma fita fina, formado por um lobo dorsal e um lobo ventral. Longitudinalmente o pâncreas em emas localiza-se no mesentério dorsal desde o fígado até a flexura cranial do duodeno, mantendo-se preso às alças duodenais por ligamentos. Histologicamente, era composto por uma cápsula delgada de tecido conjuntivo denso, com discretos lóbulos separados por tecido conjuntivo capsular, compostos por estruturas tubuloalveolares e ductos. O fígado e pâncreas de emas apresentam padrão morfológico similar ao descrito para aves domésticas.

INSECTICIDAL AND BEHAVIORAL EFFECTS OF SECONDARY METABOLITES FROM MELIACEAE ON BEMISIA TABACI (HEMIPTERA: ALEYRODIDAE)

We studied the effects of crude extracts and fractions of Azadirachta indica, Melia azedarach, Toona ciliata and Trichilia pallida on both egg and nymph mortality and embryonic development of Bemisia tabaci B biotype, using tomato plants grown in a greenhouse. Next, we studied the host selection behavioral effects on the adult whitefly under laboratory conditions. The dichloromethane extracts from all plant species and fractions of the extract from branches of T. pallida (EBTPD) and of the extract from leaves of T. ciliata (ELTCD) in dichloromethane caused mortality of nymphs, but neither affected egg viability. However, the branches of the ethanolic extract of A. indica increased the period of embryonic development of the B. tabaci. In addition, the tomato leaflets treated with the fraction of ELTCD dichloromethane (0.28%) were the least preferred by adults, reducing the number of insects resting on the tomato leaflets. The ELTCD methanol and EBTPD dichloromethane fractions inhibited B. tabaci oviposition. Thus, Meliaceae derivatives can contribute to the reduction of the B. tabaci population. The susceptibility of the B. tabaci to Meliaceae derivatives and the relevant behavioral changes of this pest are discussed.

Endophytic and rhizospheric enterobacteria isolated from sugar cane have different potentials for producing plant growth-promoting substances

Background and aims Endophytic and rhizospheric environments differ in many respects, leading to the presence of different bacterial communities at each site. However, microorganisms such as enterobacteria can be found both within plants and in the surrounding soil. Bacteria must present differences in the traits that affect such environments in order to successfully colonise them. The present study compared the plant growth-promoting potential of diazotrophic enterobacteria isolated from the rhizosphere and from within surface-disinfected plants. Methods A total of 46 diazotrophic enterobacterial strains (21 rhizospheric and 25 putatively endophytic) belonging to the Klebsiella and Enterobacter genera, which are prevalent in sugar cane plantations, were isolated from the rhizosphere and from surface-disinfected plants. Their ability to synthesise amino acids using combined nitrogen obtained from nitrogen fixation, and their ability to synthesise indole-3-acetic acid (IAA) were determined by high performance liquid chromatography. Endogenous ethylene production by the bacteria was measured using gas chromatography, and biocontrol of phytopathogenic fungi was determined qualitatively using a dual culture technique. Results The putative endophytes released significantly higher amounts of amino acids than the rhizospheric bacteria, whilst the latter produced higher quantities of ethylene and were more actively antagonistic to fungi. Both types of bacteria released similar amounts of IAA. Conclusion Endophytic and rhizospheric bacteria differ in their capacity to release plant growth-promoting substances, which may be a reflection of their adaptations and an indication of their potential impact on their natural environment.

Evaluation of HIV-1 resistance to antiretroviral drugs among 150 patients after six months of therapeutic interruption

Most of the antiretroviral (ARV) studies in Brazil have been reported in treatment-experienced and naive patients rather than in the setting of treatment interruption (TI). In this study, we analysed reasons given for TI and resistance mutations occurring in 150 HIV-1-infected patients who underwent TI. Of the patients analysed, 110 (73.3%) experienced TI following medical advice, while the remaining patients stopped antiretroviral therapy (ART) of their own accord. The main justifications for TI were: ARV-related toxicities (38.7%), good laboratory parameters (30%) and poor adherence (20%). DNA sequencing of the partial pol gene was successful in 137 (91.3%) patients, of whom 38 (27.7%) presented mutations conferring ARV resistance. A higher viral load prior to TI correlated with drug resistance (P < 0.05). Our results demonstrate that there are diverse rationales for TI and that detection of resistant strains during TI most likely indicates a fitter virus than the wild type. High viral loads coupled with unprotected sex in this group could increase the likelihood of transmission of drug-resistant virus. Thus, treating physicians should be alerted to this problem when the use of ARVs is interrupted.

Underground leaves of Philcoxia trap and digest nematodes

The recently described genus Philcoxia comprises three species restricted to well lit and low-nutrient soils in the Brazilian Cerrado. The morphological and habitat similarities of Philcoxia to those of some carnivorous plants, along with recent observations of nematodes over its subterranean leaves, prompted the suggestion that the genus is carnivorous. Here we report compelling evidence of carnivory in Philcoxia of the Plantaginaceae, a family in which no carnivorous members are otherwise known. We also document both a unique capturing strategy for carnivorous plants and a case of a plant that traps and digests nematodes with underground adhesive leaves. Our findings illustrate how much can still be discovered about the origin, distribution, and frequency of the carnivorous syndrome in angiosperms and, more generally, about the diversity of nutrient-acquisition mechanisms that have evolved in plants growing in severely nutrient-impoverished environments such as the Brazilian Cerrado, one of the world's 34 biodiversity hotspots.

Alienígenas na sala: o que fazer com espécies exóticas em trabalhos de taxonomia, florística e fitossociologia?

A presença cada vez mais disseminada de organismos exóticos (muitos dos quais se tornam invasores) nas diferentes regiões do planeta levou ao surgimento de uma linha de pesquisa na ecologia voltada às invasões biológicas. E para permitir a comunicação entre autores também foi desenvolvido um arcabouço terminológico. Mas, apesar disso, a terminologia relativa às bioinvasões tem sido ignorada por boa parte dos botânicos no Brasil. Há uma boa dose de confusão entre botânicos sobre o que seja uma espécie exótica, naturalizada, invasora, daninha e ruderal, levando ao uso inconsistente da terminologia. Além disso, diferentes autores têm adotado posturas praticamente opostas ao lidar com espécies exóticas em suas áreas de estudo, seja na preparação de tratamentos taxonômicos, seja na publicação de levantamentos florísticos e fitossociológicos. Enquanto alguns pesquisadores incluem em floras mesmo espécies cultivadas que não se reproduzem, outros excluem plantas invasoras comuns e conspícuas. Nós apresentamos aqui, em português, os principais conceitos relativos ao tema da bioinvasão e chamamos a atenção dos autores brasileiros para a necessidade de utilizar de modo consistente o arcabouço terminológico já existente na literatura. Também propomos a adoção de rótulos claros para informar quais espécies são exóticas na área estudada, diferenciando-as das nativas, e sugerimos critérios para ajudar botânicos a decidirem quando uma planta exótica deve ou não ser incluída em tratamentos taxonômicos ou levantamentos de florística.

Control of glyphosate resistant hairy fleabane (Conyza bonariensis) with dicamba and 2,4-D

Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-response curves, of glyphosate, 2,4-D, isolated dicamba and glyphosatedicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 g a.i. ha-1 for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a.e. ha-1. The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a.e. ha-1. Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a.e. ha-1 rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.