Dr. Bob Kemerait:
“Nematodes- plant parasitic nematodes, especially on corn, are the most pressing thing in my world right now.
Bottom line- a lot of row crop growers in Georgia, even now on corn, are recognizing that poor growth in their fields COULD BE nematodes!
But is it REALLY nematodes? Because stunting can be caused by a number of things: a) fertilizer spreader problems, b) pH problems, c) herbicide damage, or d) sorry dirt (whatever that is).
How do you know? Here are steps I take:
- When you visit the field, look for patterns. Potential damage (stunting, etc) from nematodes tends to be more severe in some parts of a field than others.
- Occasionally there can be a row pattern, indicative of a stopped-up nozzle where a liquid or granular nematicide was not delivering product.
- Take a shovel and carefully dig up roots focusing on finer secondary roots for typical damage and possibly galling (see picture above).
- Take soil samples. Soil cores should be taken from DIRECTLY in the root zones.
Interpreting your nematode results:
- Remember that our nematode economic damage threshold levels are based upon samples taken at harvest. That samples collected early in the season come back with ANY “bad guys” could easily be indicative of a nematode problem. We do not have spring thresholds.
- If they come back “ZERO” for parasitic nematodes: maybe its not nematodes, maybe we missed them. If you’re convinced it’s still nematodes, consider waiting a week or two and pulling samples again. Sometimes new results are more conclusive.”