Managing Nematodes

Corn: Lance Nematode

• Visible only under a microscope, lance nematodes feed from inside and outside of the corn roots.
• Timing of damage will be early spring, but the nematodes can be active throughout the season.
• These nematodes cause the most damage in sandy soils.
• Scout a month after planting and before soils warm up.

Corn:
Lesion
Nematode

• These nematodes are small transparent parasites that are visible only under a microscope.
• Most damage occurs mid-season, but lesion nematodes can be active throughout the growing season.
• Lesion nematodes feed inside of the roots, so root samples are necessary. Be careful not to expose samples to high temperatures.

Corn:
Needle
Nematode

• This transparent parasite measures about ¼’’ but can only be seen under a microscope.
• Needle nematodes feed on root tips from the outside of the roots.
• Scout a month after planting and before soils warm up.

Soybeans:
Root Knot
Nematode

• This worm-shaped parasite is invisible to the naked eye and most active when soil temperatures reach 60°F to 65°F.
• Roots of infected plants appear swollen or knotted.
• Economic threshold varies with soil type. Ask nematology lab or local Extension office for guidelines.

Soybean Cyst Nematode

• This roundworm measures about 1⁄25” long. Females are usually swollen and can be seen with the naked eye.
• Eggs are contained in dead females, which are brown and lemon-shaped and appear as cysts on roots.
• Damaged plants usually appear in patches throughout the field.