However, there are differences between the symptoms of the two problems. Iron deficiency chlorosis symptoms will appear early in the growing season, usually in early June. Yellowing due to soybean cyst nematode damage will occur later in the season, usually in July and August. Note, however, that iron deficiency chlorosis and soybean cyst nematode may occur in the same field with symptoms of both occurring on the same plant. A s mentioned earlier, above ground symptoms of soybean cyst nematode damage do not always occur consistently.
Symptoms can range from severe to nonexistent.
The intensity of the symptoms is influenced by the age and vigor of the soybean plants, the nematode population density in the soil, soil fertility and moisture levels, and other environmental conditions. Soybean cyst nematode damage usually is more severe in light, sandy soils but will occur readily in all types of soil. O ne can not rely upon above ground symptoms for identification of soybean cyst nematode infestations. If soybean yields in a particular field have leveled off or decreased for no apparent reason or if soybean cyst nematode has been confirmed on nearby land, more thorough examination of plants for below ground symptoms and a soil analysis are needed. Below-ground Symptoms M ost below ground symptoms of soybean cyst nematode injury are not unique.