Attraction of Tylenchulus semipenetrans and Meloidogyne javanica to Salts in vitro

Abstract

A bioassay to measure the attractiveness of chemicals to plant parasitic nematodes was developed. Nematodes in the center of a petri dish of washed sand were permitted to migrate for 48 hrs, after which nematodes were extracted from six cores of sand removed from the edge of the dish. The cores encompassed alternating spots of 333 l test solution or distilled water, deposited on the sand at the time of nematode infestation. A preference index (I) was calculated as the number of nematodes recovered from cores encompassing test solution as a proportion of the total nematodes recovered. Compared to water, sodium and potassium salts (0.3 M) of acetate, formate and chloride were preferred by Tylenchulus semipenetrans whereas water was preferred to those salts of citrate. Water was preferred to most of these salts by juveniles of Meloidogyne javanica with the exception of Na-acetate and Na-citrate which did not affect the migration of the nematode. Sodium carbonate and Na-bicarbonate wer