Nematodes associated with sorghum

Sorghum is a host for stubby root (Paratrichodorus spp.), lesion (Pratylenchus spp.), and ring (Criconemella spp.) nematodes. Damage from these nematodes to sorghum is usually not severe unless the crop has been monocultured for several years. Field corn and millet share many common nematode pests of sorghum. If these crops recently had a problem with nematodes in a specific field site, sorghum could possibly be affected if planted at the same location. The presence or potential for nematode problems in sorghum could be suggested by one or more of the following: 1) Cropping history of the field, e.g. two or more years production of sorghum, other grass crops or equally nematode-susceptible crops; 2) Above ground symptoms including off-color and/or stunted sorghum in spots or large areas of a field; 3) Below-ground symptoms such as small knots on roots or stunted and swollen root tips.

Symptoms

Above ground symptoms of nematode injury include stunting, thin stands, premature wilting under moderate heat or drought stress, and nutrient deficiency symptoms. Since nematode numbers can vary greatly within very short distances in the field, areas of stunted growth yield reduction, and other above ground symptoms of nematode damage vary greatly in shape, size, and distribution.

Management

Crop Rotation

Sorghum is more likely to be used as a nematode management tool in rotation with other crops than be the object of a nematode management program. Sorghum should not be used for rotation on land infested with stubby root and/or lesion root nematodes to which it is susceptible, however, it is an excellent crop to rotate with other crops to reduce numbers of several kinds of plant parasitic nematodes. Most varieties of sorghum are moderate to poor hosts of root knot nematodes (Meloidogyne spp.). Sorghum is a non-host for soybean cyst (Heterodera glycines) and reniform (Rotylenchulus reniformis) nematodes. Hence sorghum is a good management tool in the production of cotton, peanut, soybean, and many vegetable crops.