Acarine fauna of arable soils and their screening for nematophagy

A qualitative and quantitative survey of CCS Haryana Agriculutral University farm for soil acarine and nematode fauna associated with different crops revealed that overall, cryptostigmatid mites were the most frequent and abundant, followed by mesostigmatids, prostigmatids and astigmatids. The relative densities of cryptostigmatids and mesostigmatids were almost similar with annual and perennial crops. Soil mites occurred more frequently in the upper soil layer (0–5 cm) as compared to the deeper layer (15–30 cm), however, in terms of abundance, Prostigmata was more in upper layer and Mesostigrnata in deeper layer, while Crytostigmata and Astigmata were equally abundant in the two soil layers. No qualitative correlation between soil acarines and coinhabiting plant parasitic nematodes was evident.

Out of the total 37 acarine genera screened for nematophagy in vitro, most of the mesostigmatids (12 out of 14 genera) were observed to feed and survive on nematodes. Only four species viz., Hypoaspis calcuttaensis, Lasioseius sp. (Mesostigmata), Tyrophagus putrescentiae and Caloglyphus sp. (Astigmata) multiplied on nematodes. None of the 13 genera of cryptostigmatid and 8 of prostigmatid mites was found feeding or reproducing on nematodes. Uropodids (Mesostigmata) neither survived nor reproduced on nematodes.