Root-Knot Nematodes
Symptoms:
- Plants infected with root-knot nematodes are often stunted and have roots that branch profusely
- Many small galls may develop that can be similar or smaller in size than Rhizobia nodules.
Pathogen Involved:
- Root-knot nematodes are classified in the genus Meloidogyne.
- The Northern root-nematode is M. hapla (most common)
- The Columbia root-knot nematode is M. chitwoodi.
- The southern root-knot nematode is M. incognita.
- Root-knot nematodes have a wide host range, but tend not to infect grasses.
- Can increase severity of Bacterial wilt, Fusarium wilt, and Phytophthora root rot.
Time of Occurrence:
- All season
Conditions Favoring Disease:
- The root-knot nematode is found in many soil types, but it prefers sandy soils.
- Optimum temperatures for hatching, mobility, invasion and growth are 15-25C.
Disease Management:
- Have the nematode problem diagnosed correctly to select proper management practice.
- Plant resistant alfalfa cultivars.
- Crop rotation with corn or cereal grains may be somewhat helpful if broadleaf weeds are controlled.