Disease Problems. Phoma black stem was the worst disease problem for KS respondents. Sclerotinia head rot was the worst disease problem for MN and ND respondents and downy mildew was the worst disease problem for SD respondents. Phoma black stem was the worst disease problem on 26% of KS, 10% of MN, 14% of ND and 7% of SD respondents' acres. Sclerotinia head rot was the worst disease problem on 10% of KS, 36% of MN, 27% of ND and 11% of SD respondents' acres (Table 58). The percent of respondents' acres affected by Sclerotinia head rot was approximately half the amount reported for each state in 1994 (4). Downy mildew was the worst disease problem in 1997 on 2% of KS, 1% of MN, 2% of ND and 22% of SD respondents' acres. Phomopsis was the worst disease problem on 25% of MN respondents' acres and of little consequence for respondents in other states. Rhizopus head rot was the worst disease problem on 13% of KS, 1% of MN, 1% of ND and 1% of SD respondents' acres.

Rhizopus head rot was one of the three the worst disease problems on 44% of KS, 8% of MN, 2% of ND and 2% of SD respondents' acres. Phoma black stem was one of the three worst diseases on 33% of KS, 26% of MN, 36% of ND and 16% of SD respondents' acres. Sclerotinia head rot was one of the three worst diseases on 18% of KS, 70% of MN, 56% of ND and 44% of SD respondents' acres. Sclerotinia wilt was one of the three worst diseases on 0.2% of KS, 49% of MN, 50% of ND and 40% of SD respondents' acres. Phomopsis was one of the three worst disease problems on 0.3% of KS, 46% of MN, 4% of ND and 7% SD respondents' acres. Downy mildew was one of the three worst disease problems on 4% of KS, 12% of MN, 11% of ND and 23% of SD respondents' acres (Table 58).

Most respondents reported less than 10% lodging due to Sclerotinia. Sclerotinia-induced lodging of 11-20% was reported by 29% of KS, 16%of MN, 18% of ND and 20% of SD respondents. Sclerotinia-induced lodging of 21-40% was reported by 11% of MN, 8% of ND and 20% of SD respondents; and 41-90% was reported by 3% of MN and 4% of ND respondents (Table 59).

Many respondents reported less than 10% Sclerotinia head rot. Sclerotinia head rot of 11-20% was reported by 19% of MN, 9% of ND and 23% of SD respondents. Head rot of 21-30% was reported by 18% of KS, 9% of MN and 6% of ND respondents. Head rot of 31-90% was reported by 18% of KS, 6% of MN, 4% of ND and 5% of SD respondents (Table 60).

Many respondents reported less than 10% lodging due to Phoma black stem. Phoma-induced lodging of 11-20% was reported by 25% of KS, 25% of MN, 8% of ND and 8% of SD respondents who answered the question. Phoma-induced lodging of 21-40% was reported by 25% of KS, 11% of MN, 14% of ND and 8% of SD respondents. Phoma-induced lodging of 41-70% was reported by 18% of MN, 3% of ND and 8% of SD respondents (Table 61). Since Sclerotinia and Phoma may occur in the same field, there may be some crossover of lodging data between the two diseases. Evidently, disease-induced lodging was a common problem for sunflower producers.