INFLUENCE OF SOIL PROPERTIES ON PLANT NEMATODE POPULATION DENSITY UNDER Chromolaena odorata FALLOW

Abstract

Relationships between soil abiotic factors and population densities of plant parasitic nematodes spe-
cies under planted fallow of Chromolaena odorata was investigated for 2 years. Soil samples were
collected at 0 – 30 cm depth to determine population of nematode species and soil physico-chemical
properties was done at test initiation and afterwards at 6 months interval for 2 years. Four genera of
plant parasitic nematode species (Meloidogyne spp., Pratylenchus spp, Helicotylenchus spp. and
Xiphinema spp) and two free – living (Rhabditids and Dorylaimus spp.) were identified in the fallow.
Soil organic Matter and soil N were significantly higher at 2 years than at 6, 12 and 18 months. Popu-
lation density of plant parasitic nematode species significantly reduce as the fallow period extend
reaching minimum at 2 years of fallow. Highest percentage reduction of 90.3 % was observed in popu-
lation of Xiphinema at 2 years of fallow, followed by Pratylenchus with 51.5 % reduction in population
and lowest reduction of 44 % was observed in Meloidogyne population. Negative and significant rela-
tionship existed between soil physico-chemical properties and population density of plant parasitic
nematode species indicated that soil characteristics play an important role in the abundance, distribu-
tion and structure of nematode communities.