Plant Pathology Laboratory, College of Agriculture, Visva-Bharati University, Sriniketan-731236 (W.B.)
Presented at Nematology Symposium held at Coimbatore, India in February, 1981
Seasonal population fluctuations of Xiphinema insigne was studied in a fifteen years old citrus orchard in West Bengal during 1978–79. Composite soil cores were taken at depths 0–20, 20–40 and 40–60 cm under the drip line. Monthly samples were collected adjacent to the previous ones, proceeding around the tree drip line for 12 months period and the prevailing population of the nematode was estimated. Population maxima was attained in the month of March-April and August-September, corresponding with minor and major root flushes of tree respectively. In other months, the population ranged from 20–125 per 250 ml of soil. Influence of depth on population number was observed with X. insigne. There were few nematodes below 40 cm depth. Relative prevalence data in summer and winter months showed that they were drought and heat resistant.
