Soybean sudden death syndrome (SDS) is a major disease of soybean caused by the fungus Fusarium solani f. sp. glycines. The organism is difficult to detect and measure because it is a slow-growing fungus with variable characteristics.

Reliable and fast procedures are important for detection of this soybean pathogen. Procedures for extracting DNA from pure fungal cultures and fresh or dry roots were optimized.

A new procedure to test purity of DNA extracts was described. Real-time quantitative polymerase chain reaction (QPCR) assays were developed for both absolute and relative measurement of F. solani f. sp. glycines. The fungus was measured based on detection of a pathogen gene relative to a host plant gene.