No abstract

Rice plant parasitic nematodes in the Northern and Atlantic Regions of Costa Rica. The objective of this study was to identify the plant parasitic nematodes associated with the rice crop in the northern and atlantic regions of costa rica. Population growth of the main genuses was described and quantified using mathematical models, for which tables of incidence were constructed. A total of 14 rice fields in the Northern region and 15 rice fields in the Atlantic region were sampled between 2006 and 2009. nematodes from soil and roots were extracted, then numbers of nematodes of each plant-feeding genus were counted. Pratylenchus was the genus with the greatest population density in the northern region (17 024 individuals/100 g of root) followed by Meloidogyne (10 343 individuals/100 g of root). in the atlantic region the genus with the greatest population density was Meloidogyne (18 806 individuals/100 g of root) followed by Pratylenchus (8535 individuals/100 g of root). Other genera identified in the samples were Helicotylenchus, Tylenchorhynchus, Tylenchus and Criconemoides. The mathematical model that best represented the population of Pratylenchus was linear (r2 = 0.99), while the population growth of Meloidogyne fitted an exponential model (R 2 = 0.91)

<p class="p1">Durante esta investigación se muestrearon periódicamente sistemas productivos de piña y plátano en la Región Huetar Norte (RHN) y de piña en la Región Huetar Atlántica (RHA), con el objetivo de identificar los géneros de nematodos fitoparásitos asociados a estos cultivos, su frecuencia y densidad de población. También se exploró la dinámica poblacional de los principales géneros. En el cultivo de piña, los nematodos con mayor densidad de población y más frecuentemente detectados en ambas regiones estudiadas fueron <em>Pratylenchus </em>y <em>Helicotylenchus</em>. Las poblaciones de estos nematodos fueron fluctuantes en la RHN y con un crecimiento que puede explicarse mediante funciones polinómicas en la RHA. En el caso del plátano, los nematodos con mayor densidad de población y más frecuentemente detectados fueron <em>Radopholus similis</em>, <em>Pratylenchus </em>y <em>Meloidogyne. </em>Las poblaciones de estos nematodos también mostraron fluctuaciones en el tiempo.</p>

Twelve Metarhizium isolates from Costa Rica, two from Honduras and one from Nicaragua were characterised using molecular and morphological information. Two gene sequences, TEF1-α and β-TUB, identified isolates as M. anisopliae, M. brunneum and M. robertsii, and has provided new sequence information. Eleven SSRs revealed fourteen different genotypes. Morphological variability coincided with allelic diversity within species. This work provides a starting point for the application of integral biocontrol programmes, but more comprehensive and detailed surveys are warranted to understand the species composition and genetic diversity of the Metarhizium in Central America.