Biological Control of Corn Rootworm with Persistent Entomopathogenic Nematodes: An opportunity to try them on your farm.

Elson Shields, Entomology, Cornell University, Ithaca, NY

Corn rootworm (CRW) is the number one pest of corn in both NY and the U.S.  Recent NY field data are showing that the biocontrol nematodes being released against alfalfa snout beetle are also having an impact on CRW after the field is rotated from alfalfa into corn.  Research in NNY for the past 18 years has shown that a single field application of persistent biocontrol nematodes inoculates the field for multiple years and across rotations.  In 75 fields following a typical alfalfa-corn rotation, not only did the biocontrol nematodes persist for multiple years at sufficient populations to suppress soil insects, but biocontrol nematode populations were higher after 4-years of corn than in the alfalfa before being rotated to corn.  These results suggested the biocontrol nematodes were attacking CRW during the corn years of the rotation.

In test plots on the Cornell Musgrave farm, biocontrol nematodes applied in 2014 in continuous corn production prevented CRW larval feeding damage in 2016 at the same level as the best BT-CRW traited corn (Fig 1 & 2).  Even though the CRW populations were sub-economic in 2017 and 2018, the biocontrol nematodes continued to persist at levels where they can react to an economic population of CRW larvae.  We are anticipating an economic population of CRW larvae in the research plots in 2019.  Similar results were recorded in a cooperative study with Texas A&M in Dalhart, Texas under extremely heavy CRW pressure.  Cornell joint research projects against CRW continues in 2019 in NY, Texas, and Michigan with new cooperative research plots planned in Pennsylvania, Vermont and SW Kansas.  Research on impact of these biocontrol nematodes on wireworms in the Hudson Valley has shown reduction in the soil populations of these soil insects along with reduced root injury in areas where these biocontrol nematodes have been established.

Figure 1. In conventional corn (column 1), the untreated check had economic root damage from CRW larval feeding with >1.8 root nodes destroyed. Convention corn + biocontrol nematodes had less than 0.2 nodes destroyed from CRW feeding. Biocontrol nematodes were applied in June 2014 and economic levels of CRW were in 2016, two years after biocontrol nematode application.
Figure 2. Biocontrol nematodes on conventional corn reduced the root injury to the levels of the best Bt-CRW traited corn. Biocontrol nematodes were applied in June 2014 and economic levels of CRW were in 2016, two years after biocontrol nematode application.

The Shields’ lab at Cornell has just been awarded a NE SARE grant to work with NY corn producers interested in inoculating a corn field with native biocontrol nematodes to replace other CRW management practices such as Bt-CRW corn varieties.  Full establishment of the biological control nematodes requires a full year and will be fully effective in year 2.  Farmers interested in apply biocontrol nematodes to corn for corn rootworm control have the opportunity to participate in a NE SARE grant for the next 3-years.  This grant is focused on the biological control of corn rootworm with persistent biocontrol nematodes.  Participants will receive a reduced biocontrol nematode price for their first field entered into the program.  Biocontrol nematodes are applied through conventional spray equipment in 50 gallons of water per acre.  In order to use the spray equipment, 1) all screens and filters need to be removed; 2) sprayer needs to be cleaned similar to changing of herbicides and 3) Nozzles need to be replaced to fertilizer stream nozzles similar to TeeJet 0015.  The cost of the biocontrol nematodes for fields participating in the NE SARE program will be $50/ac which is a 50% reduction in the price of the biocontrol nematodes.  The application window for biocontrol nematodes on corn is between pre-planting and growth stage V4.  If farmers are interested in participating in the application of biocontrol nematodes on their fields for CRW control, they need to contact the Shields’ Lab no later than 45 days prior to a planned application.

For more information please contact your area CCE specialist:

Mike Hunter (NNY CCE):  Office phone: Cell: (315) 788-8602; Email:

Kitty O’Neil (NNY CCE):  Cell phone: (315) 854-1218, Email:

Mike Stanyard, (WNY CCE):  Phone: (315) 331-8415 Ext 123, Email:

Janice Degni, (CNY CCE):  Phone:  (607) 391-2672, Email:

Kevin Ganoe, (CNY CCE:  Phone: (315) 866-7920 Ext 230, Email:

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