Entomopathogenic nematodes for insect pest management in grass seed crops

Overview

This research program focuses on identifying and characterizing native entomopathogenic nematodes (EPNs) associated with sod webworm and other soil-dwelling insect pests in commercial grass seed fields in Oregon. The goal is to develop native EPN strains that can be reared at commercial scale for use as microbial biocontrol agents in cool-season grass seed crops. Because chemical insecticides often fail against root- and crown-feeding insects due to post-harvest residue adsorption, this work addresses a critical unmet need for effective, biologically based pest management in perennial grass seed production systems.

Technical specifications

Research approach and methods:

• Field surveys across commercial fine fescue and tall fescue production sites in Oregon, with soil core and sod samples collected weekly from at least 20 fields with recurring pest pressure
• Biweekly insect sampling from March through May to capture seasonal population dynamics
• Dissection and parasitism assessment of insect samples to detect natural infection by entomopathogenic fungi and nematodes
• Molecular diagnostic identification of indigenous EPN species, including differentiation of local strains such as the promising Steinernema strain MK754228
• Laboratory culture maintenance and infectivity trials to evaluate EPN efficacy against sod webworms and billbugs
• Population and seasonal dynamics analysis to inform timing and use patterns for biocontrol deployment

Key findings to date:

• 2020 survey identified Steinernema species associated with sod webworm populations showing 70% infection rate in a third-year fine fescue field
• 2021 expanded survey of 18 commercial field sites identified one promising EPN strain (MK754228) commonly occurring at approximately one-third of sites
• Local strains are expected to offer better adaptation to environmental extremes and longer persistence in the absence of insect hosts compared to commercially available EPNs

Technology readiness level

This research is at an early-to-mid stage of development. Initial field surveys (2020–2021) have demonstrated the presence and natural prevalence of native EPNs in Oregon grass seed systems, with one promising Steinernema strain already identified. Ongoing and planned validation includes expanded multi-site sampling, molecular species confirmation, laboratory infectivity trials against sod webworms and billbugs, and assessment of population dynamics. Commercial-scale rearing protocols and field efficacy demonstrations under grower conditions remain to be completed before the biocontrol product is ready for widespread adoption.