More than 100 soybean pathogens have been described worldwide, and about 35 of these are considered capable of causing significant economic damage on soybean. Fungi are the most numerous and harmful, followed by bacteria and viruses. White mould (or sclerotina stem rot) caused by Sclerotinia sclerotiorum is one of the most potentially damaging diseases of soybean worldwide. This soil and seed borne fungus causes significant yield losses. The sclerotia contaminate the harvested crop and this leads to widespread infection the following year when the grain is used as seed. Through contamination of seed crops, a small outbreak leads to widespread infection.