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Cover Crops for Vegetable Growers

Root Knot NematodeControl of Northern Root Knot Nematode

Meliodogyne hapla

The Northern root knot nematode can be controlled by using sudangrass. For nematode control, sudangrass is used differently from its more common application for soil conditioning, weed control and biomass production. The following instructions are specific to correcting a nematode problem in a field.

To test whether Northern root knot nematode is a problem in your field, a bioassay is available.

Land preparation
Prepare ground for seeding

Seeding rate
Drill or broadcast at 30 lb/ac.

Seeding date
July 25 to August 10

Control
September 10-15. Plants should ideally be 6 weeks old, with a range of 4 to 8 weeks.
Mow thoroughly and incorporate immediately. Roll lightly to seal surface

Tips
The shoot material must be mowed very fine before incorporation to be effective.
Repeating the sudangrass planting again withing two years increases the nematode suppression.
Plant a winter cover crop after two weeks (Sept. 25). A grain will keep the nematode population low. Oats are good if the field will be used for an early vegetable, otherwise wheat fits.

Problems
If the sudangrass cannot be incorporated on time, it will not suppress nematodes. It may even encourage them. However, it will still be useful for improving other aspects of soil health described in the regular sudangrass section.

These recommendation are based on the work of George Abawi and his colleagues.

Viane, N.M. and G.S. Abawi. 1998. Management of Meliodogyne hapla on lettuce in organic soil with sudangrass as a cover crop. Plant Disease 82:945-952.

Abawi, G.S. and T.L. Widmer. 2000. Impact of soil health managment pracrtices on soilborne pathogens, nematodes and root diseases of vegetable crops. Applied Soil Ecology 15: 37-47.