Factors influencing attraction of adult Hirschmanniella oryzae towards cabbage seedlings

Observations on various factors influencing attraction of Hirschmanniella o y zae towards cabbage roots revealed that al1 factors except coloured lights and darkness affected attraction. Responses of H. o y zae decliied as the age of the roots increased and also with an increase in the period of food deprivation of nematodes. Maximum attraction was recorded towards 4-6 day-old cabbage roots with fed nematodes as well as 2, 4 and 6 day unfed ones. Live roots attracted nematodes but roots killed by heating lost attractiveness. Maximum number of nematodes were attracted when roots were incubated for 10-12 h in 3-4 mm thick agar layer of 0.5 O/O concentration at 20-250. The nematodes showed preference to the region of root tip and aggregated most around it. Attraction decreased with increase in the distance of inoculation of nematodes from the roots.-SUME Facteurs influençant l’attraction des adultes d’Hirschmanniella oryzae par les plantules de chou L‘étude de l’influence de différents facteurs sur l’attraction des ad$tes d’H. o y zae par le chou révèle que tous ces facteurs, sauf les lumières colorées et l’obscurité, ont un effet. Les réponses d‘H. o y zae diminuent en intensité lorsqu’augmentent soit l’âge des racines soit la durée du jeûne chez les nématodes. L‘attraction maximale est observée avec des plantules de chou de 4-6 jours e