Peppermint (Mentha spp.)-Nematode, Needle

Cause Longidorus elongatus is one of several nematodes that live in soil and cause plant decline by affecting the root system. They are frequently found in the Willamette Valley of Oregon, though seldom in high numbers. Needle nematodes are migratory ectoparasites found only in soil.

Symptoms Aboveground symptoms are similar to those of root-lesion nematode infections, but roots do not show lesions. The field may have open patches of severely depressed, red-green plants with short, weak root systems. On or near the roots it may be possible to see the nematodes, which look like slender, coiled threads about 0.25 inch long and as thick as a spider web.

Sampling Only soil samples are necessary if this is the only nematode of interest. Population dynamics are similar to root-lesion nematodes: peaking in spring and again in late summer.

Cultural control

  • Rotate to corn or other grains.
  • Use clean planting stock to prevent introducing the nematode.

Chemical control

  • Preplant soil fumigation.
    • Telone II at 9 to 18 gal/A depending on soil type. Restricted-use pesticide. 5-day reentry.
  • Apply a nematicide in spring.
    • Mocap EC at 4 quarts/A in 20-30 gal/A. Apply with ground equipment, broadcast, over the field. Do not apply by air or through any type of irrigation equipment. This product is to be soil incorporated to a depth of at least 2 to 4 inches, during or immediately following application by mechanical means, including by rotary tiller, rotary hoe, springtooth harrow, or by double discing, or by immediate application of 1 to 2 inches of overhead irrigation. Repeat irrigation before soil dries. Make only one application per growing season (either preplant or after last harvest of the growing season). Do not harvest within 225 days of application.
    • Vydate L at 0.5 to 1 gal/A in enough water to cover. Apply as mint breaks winter dormancy with 0.5 to 1 inch of water within 7 days to move material into root zone. Do not apply within 21 days of harvest. 48-hr reentry. Restricted-use pesticide.

Reference Ingham, R.E., and Merrifield, K. 1996. Biology and management of nematodes in mint. IPPC Publication No. 996. Integrated Plant Protection Center, Oregon State University, Corvallis, OR. 39 p.