Effect of prey density of meloidogyne incognita on the predation efficiency of the predator, fictor composticola (nematoda: diplogasteridae)

Abstract

Predatory nematodes are important as they fed upon several prey nematode species. The diplogasterid predators are characterized by distinguished alterations in feeding apparatus. The diplogasterid predator, Fictor composticola, feeds on different categories of nematodes like microbivorous, mycophagous, and plant-parasitic nematodes. This study was undertaken under in-vitro conditions, in 1% water-agar plates, and in pots under screen house. In lab. study, 250, 500, 1000, 2000 freshly hatched juveniles of Meloidogyne incognita, and 2 females and 2 males of F. composticola were released in each plate. Observations on prey consumed were recorded after 24 and 48 hrs. of deliverance. Prey consumption of F. composticola boosted as the number of prey increased from 250 to 2000 per plate. At prey density of 500 per plate, maximum per cent consumption was observed and minimum at prey density 2000 per plate. Maximum predation found at a prey population density of 2000 individuals and minimum in 250 individuals per plate. This finding led to the conclusion of increased contacts between prey and predator at higher densities. In the pot experiment, plant height and shoot weight were reduced significantly over untreated control at 500 J2 and above. Root weight increased at 500 and 1000 levels, though it was similar to the control at 2000 level due to poor root development at this level. The number of galls and egg masses of M. incognita and final population of predator increased with increasing inoculum level of M. incognita.