1998 Dry Bean Grower Survey of Pest Problems and Pesticide Use in Minnesota and North Dakota 

 ER 58
1998

Disease Control Practices

Fungicides were used on 28% of Northarvest survey respondents' acres, down from 43% in 1997 and 61% in 1996. Fungicides were used on 28% of Minnesota and 27% of North Dakota respondents' acres, down from 59% and 37%, respectively, in 1997 and from 68% and 59% in 1996. Benlate was the most widely used fungicide in Minnesota, applied to 19% of respondents acres, followed by Topsin M, applied to 8% of their acres, and Tilt, applied to 0.4% of their acres. Benlate was the most widely used fungicide in North Dakota, applied to 13% of respondents' acres, followed by Topsin M applied to 9% of their acres, Tilt applied to 2%, Bravo applied to 2%, and maneb applied to less than 1% (Tables 10 and 11).

The percentage of acres treated by ground was nearly 9 times that treated by air for all Northarvest respondents. It was 9 times as great for Minnesota respondents and 8 times as great for North Dakota respondents (Table 10).

Minnesota respondents sprayed 27% of their acres with the benzimidazole fungicides Benlate and Topsin M for white mold control, compared with 52% in 1997, 44% in 1996 and 21% in 1995. North Dakota respondents sprayed 22% of their acres with the benzimidazole fungicides, compared to 28% in 1997, 22% in 1996 and 18% in 1995. In Minnesota 9% of respondents' acres were band sprayed (directed spray with drop nozzles between the rows) with benzimidazole fungicides and 19% were broadcast sprayed, a slightly higher percentage of band spraying than in previous years. In North Dakota, 12% of respondents' acres were band sprayed with benzimidazole fungicides and 10% were broadcast sprayed, an increase in band spraying from 1996 and 1997. Wet conditions in 1996 and 1997 may have reduced the ability of respondents to band spray in a timely manner. Use of Benlate in Minnesota was about twice that of Topsin M and in North Dakota it was about 50% higher (Table 11).

Table 10: Fungicides applied to dry beans in 1998 by respondents in Minnesota and North Dakota

  Total Acres Treatedc Acres Treated by Airc Acres Treated by Ground
Fungicidea Method of Appl.b Number % Number % Number %
Minnesota
Benlate Banded 1,880 7.5 0 0 1,880 7.5
Benlate Broadcast 2,904 11.7 378 1.5 2,526 10.1
Tilt - 208 0.8 108 0.4 100 0.4
Topsin M Banded 230 0.9 0 0 230 0.9
Topsin M Broadcast 1,812 7.3 190 0.8 1,622 6.5
Total Fungicide   7,034 28.2 676 2.7 6,358 25.5
North Dakota
Benlate Banded 7,117 9.9 0 0 7,117  
Broadcast <2,040 2.8 570 0.8 1,470 2.0
Bravo - 1,600 2.2 0 0 1,600 2.2
Maneb - 850 1.2 200 0.3 650 0.9
- 1,645 2.3 135 0.2 1,510 2.1
Topsin M Banded <1,395 1.9 0 0 1,395 1.9
Topsin M Broadcast 4,915 6.8 1,205 1.7 3,710 5.2
Total Fungicide   19,562 27.2 2,110 2.9 17,452 24.3
Northarvest
Benlate Banded 8,997 9.3 0 0 8,997 9.3
Benlate Broadcast 4,944 5.1 948 1.0 3,996 4.1
Bravo - 1,600 1.7 0 0 1,600 1.7
Maneb - 850 0.9 200 0.2 650 0.7
Tilt - 1,853 1.9 243 0.3 1,610 1.7
Topsin M

Banded

1,625

 1.7 0 0 1,625 1.7
Topsin M Broadcast 6,727 7.0 1,395 1.4 5,332 5.5
Total Fungicide   26,596 27.5 2,786 2.9 23,810 24.6

aMention of a trade name does not constitute an endorsement, recommendation nor preference over other similar fungicides.
bRespondents were not asked method of application for Bravo, Maneb or Tilt.
cRespondents’ acres only.

 

Table 11: Fungicides and application methods for white mold control in 1998 in Minnesota and North Dakota.

Fungicide Band Applied Broadcast Total
Acres %a Acres %a Acres %a
Minnesota
Benlate 1,880 7.5 2,904 11.7 4,784 19.2
Topin M 230 0.9 1,812 7.3 2,042 8.2
Totalb 2,110 8.5 4,716 18.9 6,826 27.4
North Dakota
Benlate 7,117 9.9 2,040 2.8 9,157 12.8
Topin M 1,395 1.9 4,915 6.8 6,310 8.8
Totalb 8,512 11.9 6,955 9.7 15,467 21.5
Northarvest
Benlate 8,997 9.3 4,994 5.1 13,991 14.5
Topin M 1,625 1.7 6,727 7.0 8,352 8.6
Totalb 10,622 11.0 11,721 12.1 22,343 23.1

aPercent of respondents’ acres
bTotal of Benlate and Topin M

 

Rust fungicides were used on 4% of Northarvest respondents' acres, compared to 9% in 1997 and 34% in 1996. Tilt, available in both states under a specific exemption (section 18), was used on 2% of Northarvest respondents' acres, followed by Bravo on less than 2% and maneb on less than 1%. In Minnesota, Tilt was used on less than 1% of respondents' acres. In North Dakota, Tilt was used on 2% of respondents' acres, followed by Bravo on 2% and maneb on 1% (Table 12). This dramatic reduction in use of rust fungicides since 1996 is at least partly due to increased use of pinto varieties that have resistance to the current rust races, as indicated in the section on varieties grown.

Table 12: Fungicides used for rust control in 1998 in Minnesota and North Dakota

State

 Bravo Maneb Tilt Total
Acres %a Acres %a Acres %a Acres %
Minnesota 0 0 0 0 208 0.8 208 0.8
North Dakota 1,600

2.2

850

1.2

1,645

2.3

4,095

5.7

Northarvest Total

1,600

1.7

850

0.9

1,853

1.9

4,303

4.4

aPercent of respondents’ acres
bTotal of Bravo, Maneb and Tilt