ARS | Publication request: Food and microhabitat preferences of Mononchus: a preliminary investigation

Submitted to: APS Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2011
Publication Date: June 30, 2011
Citation: Wang, K.-H., Cabos, R. 2011. Food and microhabitat preferences of Mononchus: a preliminary investigation. Phytopathology. 101:S185-S186.

Technical Abstract: Predatory nematodes are known to be potential nematode biocontrol agents, but they feed on nematodes opportunistically which means they also consume free-living nematodes and other microorgansims. Objectives of this project were to 1) determine the efficacy of a commonly occurring predatory nematode, Mononchus, to prey on plant-parasitic nematodes, and 2) to explore microhabitats favorable for Mononchus reproduction. DNA was extracted from individual Mononchus isolated from fields infested with burrowing (Radopholus similis), or root-knot (Meloidogyne spp.) nematodes. To determine if Mononchus habitually feed on plant-parasitic nematodes, PCR was conducted on the Mononchus DNA using primers specific for R. similis and Meloidogyne. The percentage of samples that tested PCR positive was evaluated to establish feeding preferences of Mononchus in cultivated soils. To examine favorable environments for Mononchus, 5 artificial microhabitats were inoculated with 6 Mononchus each. These microhabitats included: 1) 10 root-knot nematodes suspended in water in a 0.5-ml watch glass, 2) 10 g soil (frozen to free indigenous nematodes) inoculated with 40 root-knot nematode juveniles, 3) 3 g of vermicompost media, 4) water agar with a flamed carrot disc, co-cultured with Rhabditidae, and 5) 10 g soil amended with 1% (w/w) of dried sunn hemp (Crotalaria juncea) powder. Mononchus were extracted from these microhabitats 3 months after inoculation and counted.