The fungus causes browning of the xylem (water-conducting tissue) of the crown and runners (Image 2). Races 1 and 2 of this fungus are present in several watermelon-growing areas of Texas. Most commercial cultivars have resistance to to race 1, but not race 2. The fungus persists many years in soil, so watermelons should not be replanted into infested soils for at least five years.