Can biocontrol nematodes combat corn rootworm?

corn Rootworm
Western corn rootworm beetles can readily move between fields and may cause damage in locations other than where they emerged. (Purdue University photo)

HENDERSON, N.Y. — Following the successful application of biocontrol nematodes to reduce the impact of alfalfa snout beetle, northern New York farmers and a research team led by Cornell University entomologist Elson Shields are now evaluating their use to combat corn rootworm.

The biocontrol nematode protocol is also being tested in field trials in Ohio, Michigan, New Mexico and west Texas. The most recent report of research trial results is posted at


If the biocontrol nematodes are as effective against corn rootworm, farmers could potentially eliminate the need and expense for corn varieties with incorporated Bt toxin for corn rootworm or for soil insecticide use on conventional corn varieties.

Research across 85 fields on farms in northern New York where biocontrol nematodes have been applied to reduce snout beetle populations has shown that the biocontrol nematodes persist in fields after rotation to corn.

Their populations are also known to increase in corn years two to four when corn rootworm larvae are feeding on corn roots.

In trials since 2014 when the biocontrol nematodes were applied at the Musgrave Research Farm in Aurora, New York, they persisted in high levels each year.

They have reduced corn root feeding damage with results equal or at a better level of root protection than with the best BT-CRW corn variety in year two of the corn crop in the trial.

Their level of persistence has also been at a level sufficient for controlling corn rootworm larvae when the population rebounds from the wet years during the hatching period.

One of the farms participating in this research is Morning Star Farms in Henderson, New York. A spring 2018 bioassay there indicated a high level of nematode persistence two years after application.

The level is high enough to protect a new alfalfa stand there from invasion of alfalfa snout beetle in coming years.


The value of this biocontrol nematode research has now traveled from northern New York to multiple states.

For example, in west Texas, where corn rootworm adult populations have been very high, the use of biocontrol nematodes resulted in significant reduction of the pest and the root damage caused by it.

Shields notes, “Without the long-term support of the Northern New York Agricultural Development Program for the research needed to develop a solution for alfalfa snout beetle, this study to evaluate the potential to eliminate the need for BT-rootworm corn or soil insecticides on conventional varieties would not be possible here in New York or in the other states now applying the biocontrol nematodes.”


The farmer-driven Northern New York Agricultural Development Program is a research and technical assistance program for the farmers in the six northernmost counties of New York State.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Senate and administered by the New York State Department of Agriculture and Markets.

The results of past projects funded through the program are posted at

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