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.

Fungicide Use and Other Disease Management Practices

Apron-treated seed was reportedly used on 9% of KS, 56% of MN, 51% of ND and 19% of SD respondents' acres (Table 62). Since much seed is sold pre-treated, it is possible that some respondents did not know if the seed had been treated. The differences reported between SD and MN and ND are noteworthy in that no seed plants are located in SD, and most seed for SD is processed in MN or ND.

Folicur was available under a specific exemption (section 18) in KS and ND for rust control. Only one response was received from each state on its use. It was reported to provide excellent control by a KS respondent (Table 63). The ND respondent who reported using Folicur reported only 1 acre, suggesting that it may have been used to protect seed increase plots.

Non-chemical disease management practices used by respondents included crop rotation, tillage and use of resistant hybrids. Crop rotation was reported as a disease management practice on 44% of KS, 82% of MN, 61% of ND and 79% of SD respondents' acres. Tillage was reportedly used as a disease management practice on 12% of KS, 33% of MN, 26% of ND and 43% of SD respondents' acres. Use of resistant hybrids was reported as a disease management practice on 1% of KS, 21% of MN, 14% of ND and 25% of SD respondents' acres (Table 64).

Respondents were asked which hybrids were affected by Sclerotinia in 1997. A long list of hybrids was cited by respondents (Table 65). It is not clear from the data whether some hybrids were more susceptible or whether they were more frequently cited because they were more frequently planted. Thus, these data must be examined cautiously.

Bird Damage

Bird damage was most common in ND and SD with 46% of ND and 40% of SD respondents reporting more than 5% bird damage. Bird damage of 5-10% was reported by 24% of KS, 20% of MN, 26% of ND and 25% of SD respondents. Bird damage of 10-25% was reported by 4% of KS, 9% of MN, 15% of ND and 11% of SD respondents. Bird damage of 25-100% was reported by 4% of KS, 6% of ND and 4% of SD respondents (Table 66). A greater percentage of respondents in all four states reported bird damage in the higher loss categories in 1997 than in 1994 (4).

Blackbirds were the species most frequently causing damage, as reported by 78% of KS, 87% of MN, 96% of ND and 91% of SD respondents. Sparrows were the second most frequently reported bird species, cited by 15% of KS, 6% of MN, 4% of ND and 6% of SD respondents (Table 67). These data are similar to those for 1994 (4).

ND respondents spent the most on bird control: $13,129 for shotgun shells, $5,115 for exploders, $4,985 for gasoline, $5,150 for cattail control and 3,198 hours for bird control (Table 68). If hourly costs are calculated at $5.75/hr, the cost in time represents $18,389, and total costs were $46,768 for all 261 ND respondents. However, not all respondents answered this question, so costs per respondent answering the question are shown in Table 69. Each respondent who answered the question spent $515 for cattail control, $171 for exploders, $134 for shells, $87 for gasoline and 37 hours ($213).

SD respondents made the next largest expenditure on bird control: $6,560 for exploders, $3,322 for shotgun shells, $1,435 for gasoline and 2,787 hours for bird control (Table 68). Calculating $5.75/hr for bird control, the hourly cost was $16,025 and total costs for all 163 SD respondents were $27,342. Costs for each SD respondent who answered the question were $547 for exploders, $104 for shotgun shells, $110 for gasoline and 111 hours ($638), as shown in Table 69.

MN respondents reported expenditures of $970 for shotgun shells, $20 for gasoline, $10 for exploders and 5 hours for bird control (Table 68). Total costs for all 83 MN respondents, including $29 for hours spent, were $1,029. Costs per respondent who answered the question were $162 for shotgun shells, $20 for gasonline, $10 for exploders and 17 hours ($98), as shown in Table 69.

KS respondents reported expenditures of $95 for shotgun shells and 3 hours for bird control (Table 68). Total costs for all 103 KS respondents, including $17 for hours spent, were $112. Costs per respondent who answered the question were $48 for shotgun shells and 3 hours ($17), as shown in Table 69.

Bird control costs per respondent answering the question were slightly higher in ND and SD in 1997 than in 1994. They were lower in MN in 1997 than in 1994, and about the same both years in KS (4).