First field release of a predatory nematode, Mononchoides gaugleri (Nematoda: Diplogastrida), to control plant-parasitic nematodes

Abstract

Predatory nematodes are an important entity of the soil food web with biological control potential against plantparasitic nematodes (Bilgrami, 1997). Low fecundity, long life cycle, difficult culture conditions, cannibalism and susceptibility to changing environmental conditions restrict the use of mononchs and stylet-bearing predators as biological control agents. The possibility of using nematodes as biological control agents of plant-parasitic nematodes lies with diplogastrid predators (Diplogastrida). Among the advantages of diplogastrids over mononchs and stylet-bearing predators, Siddiqi et al. (2004) and Bilgrami et al. (2005) have listed ease of in vitro culture, high rates of reproduction and predation, short life cycle, and ability to detect and respond to prey attractants and rare cannibalism. Diplogastrids possess greater tolerance to unfavourable environmental conditions (Bilgrami, 1997), density-dependent predation (Bilgrami et al., 2005), ability to reduce root galling (Fauzia et al., 1998) and decrease in parasitic nematode populations in pots (Osman, 1988). This is the first report of a predatory nematode being field-released to control plant-parasitic nematodes. Our goal was to evaluate the effects of Mononchoides gaugleri (Nematoda: Diplogastrida) on naturally occurring plantparasitic and non-parasitic nematode populations in a turfgrass field. A field experiment was conducted at Rutgers University Turfgrass Station, New Brunswick, NJ, USA. The experiment was laid out in a completely randomised design within a 260 × 170 cm plot. Forty 10 cm long sections of PVC pipe (10 cm internal diam.) were driven into the ground in five vertical rows; each row was 20 cm apart and contained eight PVC pipes. The area encircled by the pipe is referred to as a microplot. Thirty-nine microplots were divided into three groups, i.e., controls I and II, and