Joedna Silva

Colonização micorrízica e nodulação radicular em mudas de sabiá (Mimosa caesalpiniaefolia Benth.) sob diferentes níveis de salinidade

The sabia (Mimosa caesalpiniaefolia Benth.) is a plant species native to the Brazilian northeast and brings together some fundamental features for use in rehabilitation programs of salinized areas, especially if associated with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (BFN). The aim of this study was to evaluate the mycorrhizal colonization and root nodulation of sabia seedlings fertilized with organic compost and irrigated with water at different electrical conductivities. The experiment was carried out in a greenhouse, in a completely randomized design with a factorial scheme of 2 (presence and absence of arbuscular mycorrhizal fungi) x 2 (presence and absence of an organic compound) x 5 levels of electrical conductivity of the irrigation water (0.7, 1.2, 2.2, 3.2 and 4.2 dS m-1), and three repetitions. The results obtained indicate that: salinity reduced mycorrhizal colonization and root nodulation of the sabia seedlings; intensifying salt-stress conditions increased the mycorrhizal dependence of the sabia seedlings; the colonization of seedlings with AMF caused increases in the root-nodule dry matter of about 1900%; the arbuscular mycorrhiza reduced the pH after soil cultivation; and the addition of vermicompost had no effect on the mycorrhizal colonization of the sabia seedlings, but did increase the production of root-nodule dry matter.

Economic injury levels and sequential sampling plans for Frankliniella schultzei in watermelon crops.

BACKGROUND The thrips Frankliniella schultzei is an important watermelon pest. Nevertheless, economic injury levels and sampling plans for this pest have not yet been determined for this crop. Thus, the objective of the present study was to determine the economic injury levels and develop sequential sampling plans for F. schultzei in conditions of low, medium and high fruit prices. RESULTS The attack of F. schultzei on watermelon plants at the vegetative stage reduced the crops productivity, which did not happen at the flowering and fruiting stage. The economic injury levels were 0.09, 0.04 and 0.02 thrips leaf-1 when the watermelon price was low (

Eficiência de genótipos de feijoeiro em resposta à adubação nitrogenada

US 62.5 t-1 ), medium (

A FEM mesh generator for large size aspect ratio problems with applications in optoelectronics

US 140.63 t-1 ) and high (

Feasible sampling plan for Bemisia tabaci control decision-making in watermelon fields

US 218.75 t-1 ) respectively. The three sequential sampling plans for F. schultzei generated for the economic injury levels resulted in similar and more rapid decisions compared with the conventional plan, especially when the pest density was high. CONCLUSIONS The three economic injury levels and the sequential sampling plans generated in the present study can be incorporated into integrated pest management programmes for watermelon crops because these plans provide a rapid and adequate control decision for F. schultzei.

Genetic erosion risk by environmental and antropic factor applied on strategies for Lychnophora ericoides conservation

Bean genotypes react differently to available nitrogen. This research aimed at selecting bean genotypes, concerning their efficiency and reaction to nitrogen absorption. The treatments consisted of twelve genotypes cultivated in two different environments, one simulating a low nitrogen level (20 kg ha -1 ) and the other a high nitrogen level (120 kg ha -1 ). The experimental design was randomized complete bocks, with four replications. The grain yield was evaluated, for classifying cultivars in relation to nitrogen use efficiency and response to application, as well as chlorophyll rates, by using a chlorophyllometer. The BRS-Grafite and Princesa genotypes were considered efficient, regarding the nitrogen fertilization, and responsive to the nitrogen application. Bean plants supplied with adequate nitrogen rates presented higher cholorophyll ( a , b and total) levels.

Spatiotemporal Dynamics of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) in Commercial Watermelon Crops

A new automatic and adaptive mesh generator for the FEM (Finite Element Method) focused on microwave and optoelectronic applications, is presented in detail. Particular attention is given to problems with large size aspect ratio. The effectiveness and robustness of this novel generator is demonstrated through careful mesh quality statistics related to the finite-element analysis of key optoelectronic structures.

Invertebrados edáficos em diferentes sistemas de manejo com café na zona da mata de Minas Gerais

BACKGROUND The silverleaf whitefly Bemisia tabaci is one of the most important pests of watermelon fields worldwide. Conventional sampling plans are the starting point for the generation of decision-making systems of integrated pest management programs. The aim of this study was to determine a conventional sampling plan for B. tabaci in watermelon fields. RESULTS The optimal leaf for B. tabaci adult sampling was the 6th most apical leaf. Direct counting was the best pest sampling technique. Crop pest densities fitted the negative binomial distribution and had a common aggregation parameter (Kcommon ). The sampling plan consisted of evaluating 103 samples per plot. This sampling plan was conducted for 56 min, costing US

Fauna do solo em sistemas de manejo com café

2.22 per sampling and with a 10% maximum evaluation error. CONCLUSIONS The sampling plan determined in this study can be adopted by farmers because it enables the adequate evaluation of B. tabaci populations in watermelon fields (10% maximum evaluation error) and is a low-cost (US

DESEMPENHO AGRONÔMICO DE CULTIVARES DE FEIJÃO EM FUNÇÃO DA ADUBAÇÃO FOSFATADA NO SUL DO ESTADO DO TOCANTINS

2.22 per sampling), fast (56 min per sampling) and feasible (because it may be used in a standardized way throughout the crop cycle) technique.