Root-Knot (Meloidogyne spp.), Lesion (Pratylenchus penetrans and other species), Soybean Cyst (Heterodera glycines)
Figure 1 – Although plant parasitic nematodes feed only on and/or in the roots of plants, above ground symptoms include poor plant vigor, stunting, yellowing, wilting and browning of leaf margins. Initial infestation occurs in patches in production fields, but it will spread by tillage and other practices. General root symptoms include: poor development, pruning, discoloration and lack of fibrous roots.
Figure 2 – Lesion nematodes cause brown to black narrow lesions on the surface of roots of hosts including soybean, cowpea and lima bean.
Figure 3 – Root-knot nematodes form galls on roots.
Figure 4a – Soybean cyst nematode on dry bean root with the females starting to protrude out of the root.
Figure 4b - Microscopic view of stained adult female with eggs.
- Coarser textured (sandy) soils
- Poor crop rotations (continuous cropping of susceptible crops)
- Movement of infested soil/equipment
- Crop stress such as soil compaction, poor drainage
- Presence of other disease-causing organisms that results in interaction and possibly increase nematode damage to the crop
- Presence of weed hosts
Courtesy of G.S. Abawi, B.D. Nelson, Jr. (North Dakota State University) and J.D. Eisenback (Virginia Polytechnic Institute and State University); Bugwood.org. 07/2011