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Integrated Pest Management Program

Department of Plant Science and Landscape Architecture, Department of Extension

Fact Sheets > Turf Landscape > Biological,Fact Sheets > Turf Landscape

Using Beneficial Nematodes for Turfgrass Insect Pest Management

Beneficial or entomopathogenic nematodes are an important biological control tool. They are very specific in attacking insects and they will not harm plants unlike plant-parasitic nematodes. There are several species of beneficial nematodes available for insect pest management. One example is Heterorhabditis bacteriophora which is the recommended nematode species for white grub management.

Beneficial nematodes have six life stages: an egg, four juvenile stages and the adult stage. Nematodes sold for pest management are in the infective juvenile stage and it is the only stage that survives outside the insect host. Infective juveniles or IJs do not feed, mate or develop outside an insect host. They have energy reserves that they use until they find a new host.

IJs enter the host through the mouth, anus, spiracles or penetrate the insect cuticle. Then, they release specific bacteria into the host which kills it in about 48 hours. The nematodes feed on the bacteria and reproduce for one to three generations within a dead host. Up to 500,000 IJs can later emerge from a host in search of a new one! While they are tough little guys against their target hosts, we have to remember that they are also sensitive to the ways we handle them. Here are ten rules to keep in mind for successful beneficial nematode use.


1. Beneficial nematodes have distinct abilities and efficacies against target hosts. Thus, it is important to carefully select nematode products according to the target pest. See Table 1 for nematode pest target groups.

Table 1. Examples of commercially available beneficial nematodes and their target pests.

Nematode Species Turfgrass Pest
Heterorhabditis bacteriophora Larvae of the Japanese, oriental, and Asiatic garden beetle, European chafer (least susceptible), billbugs, sod webworms
Steinernema carpocapsae sod webworms, cutworms, armyworms, billbugs
Steinernema feltiae crane flies
Steinernema scapterisci mole crickets

2. Nematodes are very sensitive to the storage and ambient temperature they experience. One must keep nematode products in refrigeration until they are used.


3. It is very important to water in the nematodes after application: at least 0.5 inch of water. Applications during a gentle rain are great! If possible, irrigate the area before the application and keep good soil moisture after application.


4. Apply nematodes late in the day, during a cloudy day or very early in the morning. Do not expose nematodes to direct sun light or to dry conditions.


5. Nematode application can be done with any equipment. From a simple watering can to boom sprayers. With specialized equipment, just remove any filter or any mesh smaller than size 50 and avoid using pressures higher than 300 psi.


6. Recommended rate for white grub management is 1 billion IJs per acre in 86-260 gal of water/acre.


7. When mixing the nematode formulation do not use water warmer than 80o F.
       If possible, monitor soil temperatures for optimum nematode activity:
          • below 50o F not good.
          • above 85o F also not good.


8. It is important to keep the nematode suspension under agitation to mix in oxygen and also to prevent nematodes from settling at the bottom of the container. The best approach is to apply them as soon after you have mixed the nematode formulation in water.


9. Verify the compatibility of any other pesticide used during or near the time of nematode application. Generally, carbamates, organophosphates and nematicidal compounds are not compatible.


10. Before any application check the product’s end date and nematode viability. Live nematodes are easily spotted by their wriggly movements. Once they are mixed in water, they should be active in about 30-45 min depending on formulation and water temperature. Take a small sample of the nematodes in water and place it in a clear shallow dish. Use a 15x or better hand lens to see them well. Dead nematodes will look like tiny toothpicks floating in water and exhibit no movement even after being poked at.

Live nematodes                                                                       Dead nematodes

References
Grewal, P. S., R. U. Ehlers, and D. I. Shapiro-Ilan. 2005. Nematodes as Biocontrol Agents. CABI, New York, NY.
Polavarapu, S. 1999. Optimal use of insecticidal nematodes in pest management. Workshop Proceedings. Rutgers University.
Photo credit: M. Villani. Cornell University
Illustration: A. Legrand, Univ. of Connecticut.


Prepared by Ana Legrand, Assistant Extension Professor, June 2015.
Department of Plant Science & Landscape Architecture.


Publication funded in part by the USDA NIFA Crop Protection and Pest Management Program.


The information in this document is for educational purposes only. The recommendations contained are based on the best available knowledge at the time of publication. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider and employer.