Steinernema feltiae, Beneficial nematode (Sf)
Biocontrol Agent Factsheet
S. feltiae is a nematode (tiny worm) especially effective against immature flies (including fungus gnats), and can also be used against white grubs in lawns and other pests. Sf still attack prey in relatively cool soil (down to 50 °F, 10 °C). This article focuses primarily on the use of Sf nematodes outside, and Sf strains that do not persist long-term after application.
Overview
Pests Targeted: Fungus gnat, clearwing borer, fall webworm, codling moth, pea leaf miner, white grubs
Pest Stage: Immature stages of pests (i.e., nymphs and larvae) are most susceptible
Commercially Available? Yes
Scientific Name: Steinernema feltiae (Filipjev)
Biocontrol Agent Type: Insect-killing nematode
Common Names
Beneficial nematode (Sf)
Relative effectiveness
Under the correct circumstances beneficial Sf nematodes can be extremely effective. Most pests included in the Pests Targeted table have been shown in field trials to be reduced by at least 70% when Sf nematodes are applied correctly.
Where to use
Use on a variety of ornamental or edible crops (see list in Pests Targeted section), inside or outside. Apply directly to the soil around the root zone of the plant.
About Beneficial nematode (Sf)
Beneficial nematodes, including Steinernema feltiae (abbreviated here as Sf), live in the soil and are lethal parasites of many species of insects including important pests [6]. These nematodes are living organisms and thus require specific conditions and handling to be effective. The main considerations are matching nematodes with target pest, proper storage and application temperature, avoidance of exposure to ultraviolet light (sunlight), and avoidance of nematode application drying out too quickly [6]. Beneficial nematodes do not harm plants or animals.
- Native/Non-native: Native
- Preferred climate: Humid, wet, temperate, Mediterranean, subtropical, cold tolerant
- Region: So long as the nematode species being used is matched to the appropriate host and temperatures are within the effective range for use, nematodes can be used in a wide variety of regions. Soil conditions can influence beneficial nematode success. Nematodes may have a more difficult time establishing in heavy clay soils and may need more irrigation in sandy soils [8].
- Established: This article focuses on strains of Hb that do not establish long-term in the soil and require re-application.
- Where established: Beneficial nematodes occur throughout North America, but only certain strains are commercially available, and these generally do not persist or establish in the environment.
Beneficial nematode (Sf) Appearance
Beneficial nematodes are very small and can be hard to see without a loupe/hand lens or microscope. Under magnification nematodes look like very small whitish worms about 0.4-1.5mm in length [7]. Living Sf nematodes should be moving and have a bend [8]. If nematodes appear to be not moving and are perfectly straight, they are likely dead [8].
Steinernema feltiae nematodes viewed through a microscope under 50x magnification.
Beneficial nematode life cycle
Basic overview of beneficial nematode life cycle. Nematodes are applied as infective juveniles and seek out hosts in order to reproduce.
How to Use Beneficial nematode (Sf)
Biocontrol category: Augmentative—must be released/applied repeatedly
When to use: To reduce their exposure to sunlight, beneficial nematodes should be applied in the early morning or evening. Typically Sf (Steinernema feltiae) nematodes can be effective at soil temperatures ranging from 55°F-85°F but be sure to follow directions provided by the supplier [8].
Rate: Follow instructions provided by the supplier. Research indicates a minimum of 25 nematodes per treated cm2, or 250,000 per meter2 should be used [9]. Use a sprayer nozzle with openings larger than 50 μm and an operating pressure less than 2000 kPa (290 psi)[10]. When nematodes are in suspension be sure to frequently (about every 5 minutes) agitate the container to keep the nematodes distributed equally in suspension and to supply them with oxygen [8].
Maximizing effectiveness: The most important considerations are to choose the beneficial nematode species most suited to control the target pest and conditions, and to ensure the correct application rate [6]. Check that nematodes are living with a hand lens or microscope upon arrival and before use. Completely straight nematodes that do not move when prodded are likely dead. Taking a small droplet of the well mixed nematode solution, dilute if need be and evaluate if the mortality rate is over 20%. If you do find a mortality rate of over 20%, nematodes should not be used and the supplier should be contacted [8]. Store according to manufacturer specifications and be mindful of shelf-life. Sunlight (ultraviolet radiation) is extremely detrimental to nematode survival, thus try to apply in the early morning or evening to minimize exposure [11]. Beneficial nematodes are also sensitive to drying out, so timing application with rain or irrigation pre and post application will aid in maximizing effectiveness [12;13]. Typically it is recommended to maintain soil moisture for at least 2 weeks post application. An excellent, extended, guide for using nematodes in crop settings (pdf) is available from Washington State University Extension.
Pest stage: Immature stages of pests (i.e., nymphs and larvae) are most susceptible
Mode of action: Insect-killing nematodes (infects, kills and reproduces in insects)
Conservation: Although emerging evidence for the persistence of beneficial nematodes in some crop systems suggests some species can persist, nearly all commercially-available beneficial nematodes are not conserved effectively at levels suitable for sustained pest control among years [14][15]. This article focuses on Sf nematodes that need to be re-applied as needed. Unless you are purchasing nematodes from a persistent nematode supplier, assume they will not persist over multiple weeks/seasons.
Compatibility: Compatibility can vary with specific formulations and concentrations, and should be evaluated on a case by case basis. This Compatibility Table for Beneficial Nematode (Sf) summarizes the existing information on compatibility of Sf nematodes with various pesticides and fertilizers
Risk: Insect-eating nematodes do not harm plants or animals. They have been shown to have little impact on nontarget arthropods [16].
Commercially available: Yes. Commercially available from a wide variety of suppliers. For more information see Commercial Availability of Insect-Killing Nematodes.
Any time you use a pesticide, you must read and follow the label directions and comply with all applicable laws and regulations related to pesticide use. Also be sure that any pesticide used is approved for use in your country and state/province.
Pests Targeted by Beneficial nematode (Sf)
Common Name (part of plant attacked) | Scientific Name | Crop(s) Targeted | Further Information |
---|---|---|---|
Fungus gnat+[1] (roots) | Bradysia coprophila | Greenhouse/ mushrooms | Darkwinged fungus gnats - University of Florida |
Clearwing Borer#[2] (woody trunk) | Synanthedon culiciformis | Fruit trees & ornamentals | Clearwing Moths - University of California IPM |
Fall Webworm*[3] (leaf) | Hyphantria cunea | Ornamentals | Fall webworm - University of Florida |
Codling Moth*[4] (fruit) | Cydia pomonella | Pome Fruit | Codling Moth - University of California IPM // Codling Moth Management - Washington State University |
Pea Leaf Miner+[5] (leaf) | Liriomyza huidobrensis | Vegetables, ornamentals | Pea Leaf Miner - Florida Department of Agriculture and Consumer Services (pdf) |
*Field efficacy of 70% per cited study
+Lab or greenhouse study with an efficacy of 70% or more
#Special application methodology
White Grubs
White grubs are one of many pests that can be attacked by the beneficial nematode species Steinernema feltiae.
Author
Michael Mueller
Cornell University Department of Entomology
Date: June 2022
- Special thanks to Amara Dunn, Kyle Wickings, and David Shapiro-Ilan for helpful feedback and suggestions during the writing of this article.
- Funding for completion of this article was provided by Cornell University’s Extension Outreach Assistantship.
[1] Harris, M. A., Oetting, R. D., & Gardner, W. A. (1995). Use of entomopathogenic nematodes and a new monitoring technique for control of fungus gnats, Bradysia coprophila (Diptera: Sciaridae), in floriculture. Biological Control, 5(3), 412-418.
[2] Kaya, H. K., & Brown, L. R. (1986). Field application of entomogenous nematodes for biological control of clear-wing moth borers in alder and sycamore trees. Journal of Arboriculture (USA).
[3] Yamanaka, S., Seta, K., & Yasuda, M. (1986). Evaluation of the use of entomogenous nematode, Steinernema feltiae (Str. Mexican) for the biological control of the fall webworm, Hyphantria cunea, (Lepidoptera: Arctiidae). Japanese Journal of Nematology, 16, 26-31.
[4] Lacey, L. A., Arthurs, S. P., Unruh, T. R., Headrick, H., & Fritts Jr, R. (2006). Entomopathogenic nematodes for control of codling moth (Lepidoptera: Tortricidae) in apple and pear orchards: Effect of nematode species and seasonal temperatures, adjuvants, application equipment, and post-application irrigation. Biological Control, 37(2), 214-223.
[5] Williams, E. C., & Walters, K. F. A. (2000). Foliar application of the entomopathogenic nematode Steinernema feltiae against leafminers on vegetables. Biocontrol Science and Technology, 10(1), 61-70.
[6] Shapiro-Ilan, D. I., Han, R., & Dolinksi, C. (2012). Entomopathogenic nematode production and application technology. Journal of Nematology, 44(2), 206–217.
[7] Shapiro-Ilan, D.I., & R. Gaugler. (2010). Nematodes: Rhabditida: Steinernematidae & Heterorhabditidae. In: Shelton, A. (eds) Biological Control: A Guide to Natural Enemies in North America. Cornell University. Formerly available at: http://www.biocontrol.entomology.cornell.edu/pathogens/nematodes.html. And now available at: https://cals.cornell.edu/new-york-state-integrated-pest-management/eco-resilience/biocontrol/biocontrol-biology/insect-killing-nematodes
[8] Miles, C., Blethen, C., Gaugler, R., Shapiro-Ilan, D., & Murray, T. (2012). Using entomopathogenic nematodes for crop insect pest control. Pacific Northwest Extension Publication PNW544, 1-9. https://pubs.extension.wsu.edu/using-entomopathogenic-nematodes-for-crop-insect-pest-control
[9] Shapiro-Ilan, D. I., Gouge, D. H., Piggott, S. J., & Fife, J. P. (2006). Application technology and environmental considerations for use of entomopathogenic nematodes in biological control. Biological Control, 38(1), 124-133.
[10] Georgis R., (1990). Formulation and application technology. In Gaugler, R. & Kaya, H.K. (Eds.). (1990). Entomopathogenic Nematodes in Biological Control. (pp. 173-194). CRC press.
[11] Gaugler, R., & Boush, G. M. (1978). Effects of ultraviolet radiation and sunlight on the entomogenous nematode, Neoaplectana carpocapsae. Journal of Invertebrate Pathology, 32(3), 291-296.
[12] Shetlar, D. J., Suleman, P. E., & Georgis, R. (1988). Irrigation and use of entomogenous nematodes, Neoaplectana spp. and Heterorhabditis heliothidis (Rhabditida: Steinernematidae and Heterorhabditidae), for control of Japanese beetle (Coleoptera: Scarabaeidae) grubs in turfgrass. Journal of Economic Entomology, 81(5), 1318-1322.
[13] Suggars Downing, A. (1994). Effect of irrigation and spray volume on efficacy of entomopathogenic nematodes (Rhabditida: Heterorhabditidae) against white grubs (Coleoptera: Scarabaeidae). Journal of Economic Entomology, 87(3), 643-646.
[14] Neumann, G., & Shields, E. J. (2011). Field persistence of Steinernema carpocapsae Weiser (NY001), Steinernema feltiae Filipjev (Valko) and Heterorhabditis bacteriophora Poinar (Oswego) in alfalfa fields. Great Lakes Entomologist, 44, 42-52.
[15] Lauriault, L. M., Shields, E. J., Testa, A. M., & Porter, R. P. (2020). Persistence of select introduced entomopathogenic nematodes in the US Southwest as potential biological control for whitefringed beetle in alfalfa. Southwestern Entomologist, 45(1), 41-50.
[16] Georgis, R., Kaya, H. K., & Gaugler, R. (1991). Effect of steinernematid and heterorhahditid nematodes (Rhahditida: Steinernematidae and Heterorhahditidae) on nontarget arthropods. Environmental Entomology, 20(3), 815-822.
- Steinernema feltiae nematodes viewed through a microscope under 50x magnification.
- Basic overview of beneficial nematode life cycle. Nematodes are applied as infective juveniles and seek out hosts in order to reproduce. Diagram by Bill Joyner, USDA-ARS.
Senior Extension Associate
NYS Integrated Pest Management
- (315) 787-2206
- arc55 [at] cornell.edu
PhD Student
Department of Entomology
- mbm286 [at] cornell.edu