Laboratory studies on the biocontrol potential of the predatory nematode Koerneria sudhausi (Nematoda: Diplogastridae)

Abstract

Abstract The predatory nematode Koerneria sudhausi reproduced on bacteria that developed spontaneously on a nutrient medium in Petri dishes. The nematode population had a female/male ratio of 2.9 : 1, but female nematodes could reproduce asexually on the bacteria. Each female produced about 60 progeny at 25°C in 9 days without mating. The generation time (egg to egg) at the same temperature was 8 days. Koerneria sudhausi reproduced at 17°C at the same rate as at 25°C, if the bacteria were available as a food source. When the nematode was introduced to a monoxenic culture of Meloidogyne javanica on tomato roots on agar, the nematode fed on second-stage juveniles and eggs. The nematodes introduced to M. javanica-inoculated soil before transplanting tomato seedlings reduced the root galling index in pot experiments. The results suggested that this predatory nematode, K. sudhausi, may serve as a candidate for a biological control agent against root-knot nematodes, because the nematode can be easily cultured on bacteria and achieve a high reproduction rate.