Seasonal population fluctuation behavjour of Helicotylenchus dihystera, Pratylenchus zeae and Tylenchorhynchus vulgaris in buffle grass pasture

Seasonal population fluctuation behaviour of the three plant-parasitic nematodes, Helicotylenchus dihystera, Pratylenchus zeae and Tylenchorhynchus vulgaris was studied in Jhansi, India. Approximate average population density peaks of these nematodes during April (Spring) and September (early winter) were 2.4, 2.2, 2.9 and 3.2, 3.6, 4.0; during January (mid-winter) and May (Dry-summer) falls were 1.2, 0.8, 1.6 and 1, 0.8, 1.6 nematodes per ml soil respectively. Nematode population fluctuations were affected by mean temperature, mean relative humidity, rainfall and plant growth. H. dihystera was least affected by envirmental stnss. T. vulgaris was inversely affected by high moisture which caused population decline, whereas P. zeae multiplied better in high moist conditions.