Responses of adult Hirschmanniella oryzae towards different plant roots

Experiments were performed to study the host preference behaviour of Hirschmanniella o y z a e and to observe the effects of plant root homogenate concentrations on the activity of H. o yzae. Attraction was tested in 0.5 O h water-agar in Petri-dishes towards plant roots of cabbage, carrot, radish and onion either alone or in different combinations. The effect of 20, 40, 60, 80 and 100 O/O concentrations of the above plant root homogenates was observed on the activity (head movementslminute) of nematodes. Cabbage and carrot attracted most H. oyzae while onion the least. Similarly, homogenate concentrations of cabbage and carrot roots increased activity of nematodes but those of onion and radish suppressed it markedly. The results suggest that H. oyzae shows some degree of preference and attraction depends upon the host root, attractants and activity of nematodes