Artigos Científicos - FAEST/ICEN

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/4054

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Acesso aberto (Open Access)
Bioactivity of aqueous extracts of Clibadium sylvestre (Aubl.) Baill. and Derris amazonica Killip on the aphid Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae)
(2011-12) FILGUEIRAS, Camila Cramer; FARIAS, Paulo Roberto Silva; CARDOSO, Maria das Graças; VENDRAMIM, José Djair; RAMOS, Edson Marcos Leal Soares; CANTÃO, Fernando Rodrigo de Oliveira
Studies with botanical insecticides have become more popular as an alternative to Integrated Pest Management. The purpose of this study was to evaluate the effect of leaf and fruit aqueous extracts, from the species Clibadium sylvestre, and leaves and root of Derris amazonica species at concentrations of 0, 1, 2, 4 and 8%, in the control of the aphid Myzus persicae (Hemiptera: Aphididae). Four experiments were conducted; two tests with choice preference and two tests with no choice preference, giving nine treatments and five repetitions. Phytochemical screening was carried out from the leaves and fruit of the species C. sylvestre and leaves and root of D. amazonica. Evaluations of mortality, number of nymphs, and deterrence index of the insects were conducted 24, 48 and 72 h after the application of the extracts. The aqueous extracts tested from C. sylvestre fruit concentrations had the highest mortality compared to the control; in the analysis of the number of the nymphs, the aqueous extract from fruit at 8% concentration had a higher efficiency than the other treatments. The D. amazonica leaves extract at 1% concentration showed the highest mortality and the lowest number of nymphs. The D. amazonica root extracts increased mortality at all concentrations tested, and the 8% concentration had the fewest nymphs. All treatments showed a deterrent effect. The 72 h period showed the greatest effect of the extracts, on two species of insects.
Acesso aberto (Open Access)
Economic injury level of citrus black-fly in commercial ‘pera-rio’ orange area
(Universidade Federal do Pará, 2017-07) LIMA, Bruno Gonçalves; FARIAS, Paulo Roberto Silva; RAMOS, Edson Marcos Leal Soares; SALES, Tiago de Melo; SILVA, Anderson Gonçalves da
Citrus black-fly (Aleurocanthus woglumi) has become an important pest in many citrus-producing regions in Brazil, causing direct and indirect damage to plants. Due to the lack of studies on the economic injury level (EIL) for this insect, control efficiency can be impaired. The objective of this research was to determine the EIL and the influence on the productivity of orange trees colonized by A. woglumi nymphs in an orchard located in the municipality of Capitao-Poço, Pará, using statistical analysis and damage prediction models through multivariate statistics. Population levels varied along the experiment. Infestation by A. woglumi nymphs negatively influenced orange production in Capitao-Poço with the highest population densities of the pest associated to lower plant productivity. The level of A. woglumi infestation on orange trees resulting in economic losses was, on average, 47.63% of infested plants, ranging from 22.75 to 89.92% and EIL is expressed by equation Y = 97.39 – 8.43x.

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Navegando Artigos Científicos - FAEST/ICEN por Autor "FARIAS, Paulo Roberto Silva"