Standardisation of sampling zones for detection and survey of Radopholus similis in the rhizospheres of variqus crops

Investigations were carried out to standardise the sampling zones for maximum recovey of the burrowing nematode, Radopholus similis within the rhizospheres of arecanut, coconut, banana and black pepper. The young, tender, white to orange coloured main roots of coconut, arecanut and banana and white feeder roots of black pepper were found to harbour maximum R. similis. Main roots of coconut recorded maximum per gram root population compared to arecanut, banana and black pepper. In coconut, the maximum population occurred in roots at a distance of 100 cm from the bole of the palm at a depth of 75–100 cm, whereas in arecanut it was at 75 cm distance to a depth of 51–75 cm. In both banana and black pepper the maximum population occurred at 50 cm distance from the pseudostem/vine base to a depth of 20–40 nnd 21–30 cm respectively. Irrespective of crops, distances anti depths, population of R. similis in soil was negligible.