Diagnostic of plant parasitic nematodes and its population dynamics in two pineapple cultivation systems in Costa Rica

Abstract

The presence of genera, population density and population dynamics of plant parasitic nematodes in two pineapple plantations (Ananas comosus var. Comosus) located in Costa Rica, were determined.

The study included the evaluation of soil and roots in plants of two to twelve months with the objective of determine the population dynamics of nematodes in different plots of plantations of pineapple, in conventional and organic farming systems in the Región Huetar Norte and Región Huetar Atlántica of Costa Rica. Commercial lots were carefully chosen, and sampled monthly in the course of February to December in the years 2006, 2007 and 2008.

Every sample was processed for characterization and quantification of plant parasitic nematodes.

The diagnosis allowed the identification of seven genera of plant parasitic nematodes present in soil samples: Helicotylenchus spp, Meloidogyne spp, Pratylenchus spp, Tylenchus, Tylenchorhychus. At the same time it was observed free living nematodes. Helicotylenchus spp was the most frequently detected nematode. Pratylenchus spp. and Helicotylenchus spp showed the highest populations in soil samples.

Nematodes more frequently observed in roots of pineapple plants under organic system were Criconemella spp, Helicotylenchus spp and Pratylenchus spp. While Helicotylenchus spp. and Pratylenchus spp. were observed in the 100% of the soil samples. In roots and soil of pineapple plants under conventional system, Helicotylenchus spp. was the most frequently nematode detected. The genus Pratylenchus spp. presented the highest population density in the root samples, with an average of 1009.83 individuals/100 g of root in the organic systems, and 1075.22 individuals/100 g of root in the conventional systems.

In the organic managed plantations it was observed a greater diversity of nematodes, nine plant parasitic genera were observed: Pratylenchus spp, Helicotylenchus spp, Meloidogyne spp, Hoplolaimus spp, Tylenchus spp, Criconemella spp. and Xiphinema spp. and free-living nematodes too. Whereas in the conventional managed plantations six plant parasitic genera were observed: Pratylenchus spp., Helicotylenchus spp., Nacobus spp., Tylenchus spp., Meloidogyne spp., Criconemella spp. and free living nematodes too.

In the root samples, nematode genera identified were five: Helicotylenchus spp, Meloidogyne spp, Pratylenchus spp, Rotylenchus spp. and free-living nematodes. The highest population of plant parasitic nematodes observed in root samples corresponds to the genera Helicotylenchus spp. and Pratylenchus spp.

In conventional managed plantations seven genera of plant parasitic nematodes were observed in soil samples: Pratylenchus spp., Helicotylenchus spp., Tylenchus spp., Meloidogyne spp., Criconemella spp., Hoplolaimus spp. Tylenchorhynchus spp. and free-living nematodes, while in soil samples of organic managed plantations six genera of plant parasitic nematodes were observed Pratylenchus spp., Helicotylenchus spp., Tylenchus spp., Meloidogyne spp., Criconemella spp. Rotylenchus spp. and free living nematodes.