Soybean cyst nematode (Heterodera glycines)

soybean root showing small cysts

Soybean cyst nematode: biology

When temperatures and moisture levels are adequate in the spring, worm-shaped SCN juveniles hatch from an egg into the soil. There are over 200 eggs per female, and eggs can survive more than 10 years dormant in the soil.

The soybean roots act as beacons for food to these young juvenile nematodes, which have no problem finding a point of entry and forming their feeding site inside the root. This feeding site, known as the syncytium, opens an entryway for other pathogens and increases the soybean plant's susceptibility to a number of soilborne pathogens, such as Pythium, Rhizoctonia, Phytophthora and Fusarium.

Soybean cyst nematode: damage description

Soybean plants show slight to severe stunting with slight to severe chlorosis. Yield decline is gradual over several years. Nodulation is diminished, and the canopy is slow to close. Symptoms can be similar to those of nitrogen and/or potassium deficiency. Some root decay. Tiny cysts on roots first appear as white to yellow, lemon-shaped females on the root surface; then the cysts turn dark brown with age. These cysts are much smaller than the nitrogen nodules on the roots. Affected plants tend to develop in a circular or oval area in a field. If SCN are suspected, check roots for cysts.

In 2013, we began detecting SCN presence in Ontario. Findings are indicated on this interactive map.

Legend

Soybean cyst nematode: management

Rotation is a key component in any nematode management plan. Rotational crops, such as corn, diminish the SCN population in a field. Without a source of food, any SCN eggs that hatch will die.

  1. Include non-host crops in rotation
  2. Rotate resistant soybean varieities
  3. Use different sources of resistance
Once SCN is found in a field, you need to start managing it! It is easier to keep a low SCN population low than to decrease a high population. You can reduce populations but you cannot eliminate SCN from a field.
Pasteuria nishizawae, the active ingredient in Clariva pn, is a proven natural enemy to SCN. In essence, Pasteuria nishizawae is a parasite of a parasite of soybean. Its spores latch onto the nematodes. Instead of swelling with eggs, the infected SCN now fills up with spores. Similar to an over-inflated balloon, the SCN expands beyond its limits and dies.

Recommended solution

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Saltro® is a canola fungicide seed treatment for suppression of seed and air-borne blackleg, and soybean fungicide seed treatment for sudden death syndrome management.

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