Publications by authors named "Devika M De Costa"

Background: In this study, we surveyed through a structured and pilot-tested questionnaire, the practices of pesticide usage by small-scale (< 1.25 ha) chilli and tomato farmers from four districts of Sri Lanka and their perceptions on the effectiveness of pesticides and willingness to adopt integrated pest management (IPM).

Results: We found significant (P < 0.

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Okra yellow vein mosaic disease (OYVMD) causes serious loss in okra production in Sri Lanka. Therefore, screening of resistant okra verities is an essential need to control the disease. As the available qualitative and semi-quantitative methods failed to detect latent infection the present study aimed to develop a quantitative PCR (qPCR) assay to detect and quantify one of the OYVMD causing agent, symptom modulating satellite molecules.

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We identified a putative pal gene cluster (palR, palE, palF, palG, palK, palA, and palB) in the plant-tumorigenic bacterium Agrobacterium tumefaciens MAFF301001; by sequencing analyses, this cluster was found to be involved in palatinose transport, and its functional importance was revealed by mutational analyses. The pal gene products were highly homologous to those of putative trehalose/maltose ABC-type transport systems but were not essential to bacterial growth on trehalose. Insertion mutations in the palK and palE genes showed the necessity of these genes for bacterial growth and chemotaxis with palatinose as the carbon source, but no inhibition of tumorigenesis was observed.

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