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Growers can now tap into the soybean plant’s own defense mechanism to combat SCN.

Soybean cyst nematode (SCN) has been found in most soybean-producing areas in the world. SCN was first found in North America in North Carolina in 1954 and since then has spread to many of the fields in at least 31 soybean-producing states and Canada. SCN is the most destructive pathogen of soybeans in the United States with annual yield losses due to SCN estimated at more than $1 billion annually.

The question for agronomists and growers is what can be done to manage SCN populations.

Once present in the soil, SCN can’t be eliminated. However, it can be managed, which will minimize its egg production and maximize crop yields. Currently, the most effective SCN management practices are planting resistant varieties and rotation to non-host crops. Non-host crops reduce the number of nematodes in the soil because the SCN is not able to find suitable roots to feed on, resulting in reduced egg production. Common non-host crops include alfalfa, barley, corn, cotton, oats, rice, sorghum, sunflower, wheat, white and red clover. Today there are multiple races of SCN, and sources of genetic resistance are few and may no longer control the biotypes residing in the soil.

Beside genetic resistance and rotation, there are several seed treatments like VOTiVO^® from Bayer Crop Sciences, Clariva^® from Syngenta and N-Hibit^® from Plant Health Care, Inc. N-Hibit contains the Harpin αβ plant protein.

How does Harpin αβ help reduce SCN? Harpin αβ protein acts by initiating the plant's own internal defense system. Unlike other pesticides, Harpin αβ only improves the plant’s ability to defend itself, which precludes developing resistance. And like many of the other fungicides applied, Harpin αβ also enhances plant growth and improves yield.

Plants have the ability to defend themselves against nematodes, but that trait needs to be activated.  Once this trait is activated by Harpin αβ, the plant generates multiple mechanisms to protect itself: 

• Thickened root surfaces reduce the ability of nematodes to penetrate
• Formation of reactive oxygen compounds kill the cells surrounding nematode feeding sites, resulting in nematodes failing to reach maturity and lay eggs
• Improved healing reduces disease entry at nematode entry sites
• Alterations in root exudates confuse nematodes, reducing their ability to locate suitable roots for reproduction

Harpin αβ has been granted registration by the Environmental Protection Agency.  For more EPA-related information, refer to the Harpin αβ protein (006506) Fact Sheet. 

The Federal Register Notice can be viewed here.

Kevin Staska is a Field Development Manager at Plant Health Care, Inc.