Sorghum seedling blight
These seedlings have stunted growth and chlorosis, usually present in poorly drained or compacted soil areas, caused by seedling blight, which also can cause wilting. Knowing the organism responsible for the seedling blight is important when selecting seed treatments. Seedling blight caused by Fusarium fungi are most often found in warmer, drier soils, especially where soil pH is low. If the subcrown internode is killed before the secondary roots become established, the plant usually dies. Blight caused by Pythium species are most frequently a problem in cooler, wetter soils. A constriction of the stem (damping-off) just below the soil line is a key symptom of Pythium seedling blight.
Pest photo source
KSU Sorghum Production Problems