Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum (FOV) race 4 has emerged as the dominant disease concern for cotton growers in California. Originally described from Asia, race 4 has spread into multiple counties in the San Joaquin Valley (SJV) since its discovery in one California field in 2001. Most commercial varieties of cotton are susceptible to race 4, especially Pima (Gossypium barbadense) varieties. Because the SJV produces significant quantities of seed cotton and transmission of FOV through acid-delinted seed has been well established, there is an urgent need for an effective means of eliminating the fungus from infected seed. Preliminary experiments showed Fusarium prevalence to decrease over time with high temperature dry heat treatments but seed vigor declined as well. For two months (end Oct-mid Dec), we will test the effect of lower dry heat temperatures on the 2007 crop of seed from Louisiana collected from race 1-infected plants. The experiment will continue until April but we will be sharing preliminary results from the first two months.