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2003 Plant Management Network.
Accepted for publication 4 March 2003. Published 25 March 2003.


Effect of Diseases on Soybean Yields in the United States and Ontario (1999 to 2002)


J. A. Wrather, University of Missouri Delta Research Center, P.O. Box 160, Portageville 63873; S. R. Koenning, North Carolina State, Raleigh 27695; and T. R. Anderson, Harrow Research Center, Harrow, Ontario NOR1 GO Canada


Corresponding author: J. A. Wrather. wratherj@missouri.edu


Wrather, J. A., Koenning, S. R., and Anderson, T. R. 2003. Effect of diseases on soybean yields in the United States and Ontario (1999-2002). Online. Plant Health Progress doi:10.1094/PHP-2003-0325-01-RV.


Introduction

High yields are critical to soybean producer profit margins, especially during periods of low prices for soybean. Soybean yields in the United States and Ontario have been suppressed by diseases in the past (8). Consequently, income derived from this crop is less than optimal. This financial loss is important to rural economies and to the economies of allied industries in urban areas.

Research must focus on management of diseases that cause extensive losses, especially when funds for research are limited. Clearly, knowledge of the losses caused by various soybean diseases is essential when prioritizing research budgets.

The Southern Soybean Disease Workers (SSDW) began reporting estimated soybean losses due to diseases in the southern United States in 1974, and a summary of these data from 1974 to 1994 has been published (6). Estimates of soybean yield losses due to diseases for the United States from 1996 to 1998 have been published (7).

The objective of this project was to compile estimates of soybean yield losses due to diseases for each soybean producing state in the U.S. and Ontario from 1999 to 2002. The goal was to provide this information to help funding agencies and scientists prioritize research objectives and budgets.

This report was prepared through a joint effort of North Central Regional Committee on soybean pathology (NCR-137) and the Southern Soybean Disease Workers. One objective of these two groups is to monitor and publicize the development of new or recurring diseases of soybean in North America.


Methods for Developing Loss Estimates

Individuals from each soybean-producing state in the US and the Province of Ontario were asked to estimate the percent of yield loss that each soybean disease caused in their state or province during 1999 to 2002. Dr. A. Tenuta and Dr. T. Anderson provided the estimates for Ontario, and those that provided estimates by state are listed in Table 1. These scientists developed their estimates from field surveys, research plot data, and questionnaires to field workers and extension staff. Most individuals used several of these methods and consulted with their colleagues to develop a percent loss estimate. The estimates of yield losses in Iowa due to soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) for 1999 to 2002 were based on the following assumptions and conditions. First, 74% of Iowa crop land was infested with SCN (5) at a population density of 4,340 eggs per 100 cc of soil or greater. Second, 35% of Iowa farmers grew maturity group I soybean cultivars, 35% grew maturity group II, and 30% grew maturity group III. Third, 95% of Iowa farmers grew SCN-susceptible cultivars, and 5% grew SCN-resistant cultivars. Fourth, yield loss with SCN-susceptible varieties was 33.9%, and yield loss for SCN-resistant cultivars was 21.5% (4). Fifth, results of cultivar trials in SCN-infested and noninfested fields were representative of results that would be obtained throughout Iowa. Production losses for all areas were based on estimates of yield in the absence of disease.


Table 1. Individuals that contributed estimates of soybean
yield suppression due to diseases by state.

State Individual
Alabama B. Gazaway and E. Sikora
Arkansas C. Coker
Delaware B. Mulrooney
Florida T. Kucharek
Georgia R. Davis
Iowa X. B. Yang and G. Tylka
Illinois W. Pedersen
Indiana S. Abney
Kentucky D. Hershman
Kansas D. Jardine
Louisiana K. Whitam
Michigan P. Hart and F. Warner
Maryland A. Grybaushas
Minnesota J. Kurle
Missouri A. Wrather and L. Sweets
Mississippi G. Sciumbato
North Carolina S. Koenning
North Dakota B. Nelson
Nebraska L. Giesler
Ohio A. Dorrance
Oklahoma P. Pratt
Pennsylvania B. Pennypacker
South Carolina J. Mueller and C. Drye
South Dakota M. Draper
Tennessee M. Newman
Texas J. Krausz
Virginia P. Phipps
Wisconsin C. Grau
Ontario A. Tenuta and T. Anderson


Estimates of Soybean Yield Suppression

During 1999, 67 million metric tons (t) of soybean were produced in the United States from 29.3 million ha, 70 million t were produced from 29.4 million ha in 2000, 73 million t were produced from 29.5 million ha in 2001, and 68.3 million t were produced from 29.0 million ha in 2002. Ontario farmers produced 2 million t of soybean from 850,000 ha in 1999, 2 million t of soybean from 890,000 ha in 2000, 1 million t from 850,000 ha in 2001, 1.8 million t from 835,000 ha in 2002.

Disease reduced soybean production in the United States and Ontario in 1999 to 2002 (Appendix, Tables 2-9). Losses to individual diseases varied among regions in the United States.

The total soybean yield losses to diseases in the United States and Ontario varied among years (Appendix, Tables 10 and 11).

Soybean cyst nematode (Figs. 1 and 2) caused more estimated total losses to soybean in Ontario during 1999 to 2002 than any other disease, and it was followed in order by seedling diseases, Phytophthora root and stem rot (Fig. 3) [Phytophthora sojae (Kaufman & Gerdemann)], and Sclerotinia stem rot (Fig. 4) [Sclerotinia sclerotiorum (Lib.) de Bary] (Appendix, Table 10). In the United States, SCN caused more estimated losses to soybean during 1999 to 2002 than any other disease, and it was followed in declining order by Phytophthora root and stem rot, sudden death syndrome (Fig. 5) [Fusarium solani f. sp. glycines (Roy)], and charcoal rot (Figs. 6 and 7) [Macrophomina phaseolina (Tassi) Goidanich] (Appendix, Table 11).



Fig. 1. This crop shows SCN damage.

Fig. 2. White females of Heterodera glycines on a soybean root.


 

Fig. 3. Soybean plants killed by Phytophthora root and stem rot.

 

Fig. 4. Bleached soybean stems due to Sclerotinia stem rot.


 

Fig. 5. Foliar symptoms of sudden death syndrome.

 

Fig. 6. Premature defoliation caused by charcoal root rot.


 

Fig. 7. Sclerotia of Macrophomina phaseolina in soybean stem tissue.

 

Losses to SCN declined slightly in the United States from 4.2 million t in 1999 to 3.6 million t in 2002. These losses are lower than those reported for 1998 (7.6 million t) (8). The declines from 1998 to 2002 were possibly due to greater farmer awareness of SCN through the efforts of the Soybean Cyst Nematode Coalition in the north central states and increased planting of resistant cultivars in infested fields. The yield suppression due to SCN in the United States during 2002 was valued at $783.8 million ($216/t).

Phytophthora root and stem rot caused losses of soybean in most regions in the United States and in Ontario from 1999 to 2002. The estimated yield losses in the United States due to this disease did increase from 0.7 million t in 1999 to 1.2 million t in 2002. This increase only occurred in northern regions of the United States and may be caused by the changes in virulence of Phytophthora isolates from this area (1). The yield suppression due to this disease in the United States during 2002 was valued at $252.1 million ($216/t).

Losses caused by Sclerotinia stem rot (SSR) were greater in Ontario during 2000 than 1999, 2001, and 2002 and were greater in the United States for 2000 than 1999, 2001, and 2002. This disease has been a problem only for North Dakota, South Dakota, Wisconsin, Iowa, Illinois, Minnesota, and Indiana. Declines in the losses due to this disease in the United States from 1997 (957,000 t) (8) to 2002 (74,108 t) were possibly due to increased planting of less susceptible cultivars, changes in management practices and/or changes in weather patterns.

Losses to charcoal rot in the United States declined from 1999 to 2002, and they also declined in Ontario during these years. The reasons for these declines are not clear. Because resistant cultivars are not available for planting, these declines must, in part, be due to changing weather patterns. The yield suppression due to charcoal rot in the United States during 2002 was valued at $173.8 million ($216/t).

Sudden death syndrome (SDS) yield losses occurred primarily in Arkansas, Iowa, Illinois, Indiana, Kentucky, Missouri, and Tennessee during 1999 to 2002. Losses to this disease were especially severe in Iowa, Illinois, and Indiana. Scherm and Yang (3) determined that weather patterns were more conducive for this disease for the central than any other area of the United States, and our data confirm their observation. The yield suppression due to SDS in the United States during 2002 was valued at $157.4 million.

Reliable estimates of crop losses to diseases based on precise methodology using crop surveys and crop loss models have been very useful for defining the severity of various diseases (2). It is hoped that estimates of soybean yield losses to diseases based on precise methodology will be available in the future.

Plant diseases reduced soybean yield in North America from 1999 to 2002. Yield losses may have been worse if not for the use of disease management strategies and systems in most states. To reduce disease losses, university research and extension efforts must be expanded to provide more effective preventive and therapeutic disease management strategies and systems to producers.


Acknowledgments

This work was supported, in part, by the Missouri Agricultural Experiment Station. This work was also supported by the U.S. Soybean Farmer Checkoff through the United Soybean Board, USDA Grant 00-34113-8968, and the Ontario Soybean Growers.

The authors thank Joyce Elrod for her efforts in this project.


Literature Cited

1. Abney, T. S., Melgar, J. C., Richards, T. L., Scott, D. H., Grogan, J., and Young, J. 1997. New races of Phytophthora sojae with Rps 1-d virulence. Plant Dis. 81:653-655.

2. James, W. C., Teng, P. S., Nutter, F. W. 1991. Estimated losses of crops from plant pathogens. Pages 15-51 in: CRC Handbook of Pest Management. CRC Press, Boca Raton, FL.

3. Scherm, H., and Yang, X. B. 1999. Risk assessment of sudden death syndrome of soybean in the north-central United States. Agric. Sys. 59:301-310.

4. Tylka, G. L., and Souhrada, S. K. 1999. Evaluation of soybean varieties resistant to soybean cyst nematode in Iowa-1998. Iowa State University Coop. Ext. Serv. Publ. No. IPM-52.

5. Workneh, F., Tylka, G. L., Yang, X. B, Faghihni, J., and Ferris, J. M. 1999. Assessment of soybean brown stem rot, Phytophthora sojae, and Heterodera glycines in the north central United States using area-frame sampling: prevalence and effects of tillage. Phytopathology 89:204-211.

6. Wrather, J. A., Chambers, A. Y., Fox, J. A., Moore, W. F., and Sciumbato, G. L. 1995. Soybean disease loss estimates for the southern United States, 1974 to 1994. Plant Dis. 79:1076-1079.

7. Wrather, J. A., Stienstra, W. C., and Koenning, S. R. 2001. Soybean disease loss estimates for the United States from 1996 to 1998. Can. J. Plant Pathol. 23:122-131.

8. Wrather, J. A., Anderson, T. R., Arsyad, D. M., Tan, Y., Ploper, L. D., Porta-Puglia, A., Ram, H. H., and Yorinori, J. T. 2001. Soybean disease loss estimates for the top 10 soybean producing countries in 1998. Can. J. Plant Pathol. 23:115-121.







Appendix


Table 2 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 1999a.

Diseases AL AR DE FL GA KY LA MD
Anthracnose 2,794 12,446 Tr 254 0 3,048 6,350 Tr
Bacterial diseases Tr 254 0 0 0 0 Tr 0
Brown spot 0 0 0 0 0 508 0 0
Brown stem rot 0 0 0 0 0 0 0 0
Charcoal rot 508 103,378 7,366 254 254 61,214 25,654 20,066
Downy mildew 508 254 0 0 0 0 Tr 0
Frogeye leaf spot 508 2,540 0 0 508 0 1,270 0
Fusarium root rot Tr 254 0 0 0 0 Tr 0
Other diseasesb 0 0 0 0 254 0 1,270 0
Phomopsis seed rot 0 254 0 254 254 1,270 6,350 0
Phytophthora rot 0 1,016 0 0 0 0 1,270 0
Pod and stem blight 2,794 15,494 Tr 0 0 1,270 12,954 Tr
Purple stain 254 6,350 0 0 0 0 19,304 0
Rhizoctonia aerial blight 0 2,540 0 0 0 0 12,954 0
Root-knot nematodes
& other nematodesc
2,794 40,132 Tr 0 3,302 0 16,256 0
Sclerotinia stem rot 0 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 254 25,908 762 254 508 508 Tr 2,032
Southern blight 0 254 0 0 254 0 Tr 0
Soybean cyst nematode 1,778 32,258 4,318 254 2,794 12,192 6,350 11,938
Stem canker 0 6,350 Tr 0 508 0 Tr Tr
Sudden death syndrome 1,016 2,540 0 0 0 0 0 0
Virus Tr 1,016 0 0 0 508 1,270 0

a Rounding errors may occur; Tr = trace.

b Other diseases were: red crown rot caused by Cylindrocladium parasiticum in NC, GA, and VA; target spot in LA; and Phymatotrichum root rot in TX.

c Other nematodes were: stubby root in VA; Columbia lance in NC and GA; lance in LA; and Reniform in AL, AR, and NC.


Table 2 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 1999a.

Diseases MS NC OK SC TN TX VA TOTAL
Anthracnose 6,350 762 762 3,810 1,016 8,382 Tr 45,974
Bacterial diseases Tr 0 Tr 0 0 0 0 254
Brown spot 1,524 0 0 254 1,016 508 Tr 3,810
Brown stem rot 0 0 0 0 0 0 0 0
Charcoal rot 220,726 3,556 11,684 254 8,382 5,588 0 468,884
Downy mildew 0 0 Tr 254 0 0 0 1,016
Frogeye leaf spot 762 0 0 254 5,588 508 Tr 11,938
Fusarium root rot 0 0 0 0 0 508 Tr 762
Other diseasesb 0 432 0 0 0 254 Tr 2,210
Phomopsis seed rot 0 762 762 0 0 2,794 3,048 15,748
Phytophthora rot 254 1,778 1,524 0 508 254 Tr 6,604
Pod and stem blight 31,496 7,112 3,048 3,048 0 1,270 Tr 78,486
Purple stain 10,922 0 1,270 1,016 0 2,794 0 41,910
Rhizoctonia aerial blight 0 0 0 0 0 254 0 15,748
Root-knot nematodes
& other nematodesc
Tr 10,414 254 18,542 1,524 508 1,778 95,504
Sclerotinia stem rot Tr 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 7,874 0 2,286 254 8,382 1,016 1,524 51,562
Southern blight Tr 508 Tr 4,572 508 508 Tr 6,604
Soybean cyst nematode 1,524 50,292 4,318 11,176 22,098 0 5,842 167,132
Stem canker Tr 0 0 0 508 254 0 7,620
Sudden death syndrome Tr 0 0 0 1,778 254 0 5,588
Virus 7,874 1,778 254 5,588 0 254 254 18,796

a Rounding errors may occur; Tr = trace.

b Other diseases were: red crown rot caused by Cylindrocladium parasiticum in NC, GA, and VA; target spot in LA; and Phymatotrichum root rot in TX.

c Other nematodes were: stubby root in VA; Columbia lance in NC and GA; lance in LA; and Reniform in AL, AR, and NC.



Table 3 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states and Ontario during 1999a.

Diseases IA IL IN KS MI MN MO
Anthracnose 0 Tr Tr 0 0 -- 0
Bacterial diseases 0 0 Tr 0 0 -- 0
Brown spot 0 Tr 12,649 0 0 -- 0
Brown stem rot 0 37,389 139,014 0 0 -- 0
Charcoal rot 0 186,944 25,273 237,134 0 -- 101,651
Downy mildew 0 0 0 0 0 -- 0
Frogeye
leaf spot
0 0 6,325 0 0 -- 0
Fusarium
root rot
0 0 Tr 23,724 0 -- 20,320
Other diseasesb 0 37,389 0 0 0 -- 0
Phomopsis eed rot 0 24,917 Tr 0 0 -- 10,160
Phytophthora rot 77,902 124,638 221,183 23,724 0 -- 60,985
Pod and stem blight 233,680 Tr Tr 5,918 0 -- 0
Purple stain 77,902 0 Tr 0 0 -- 0
Root-knot nematodes
& other nematodes
0 0 0 0 11,024 -- 4,064
Sclerotinia stem rot 0 Tr 0 229 0 -- 0
Seed diseases 0 0 6,325 0 0 -- 0
Seedling diseases 0 24,917 25,273 59,284 0 -- 20,320
Southern blight 0 0 0 0 0 -- 0
Soybean cyst nematode 2,648,229 623,189 252,781 23,724 220,218 -- 101,905
Stem canker 0 24,917 18,948 5,918 0 -- 0
Sudden death syndrome 233,680 124,638 113,741 229 0 -- 10,160
Virus 155,778 0 0 Tr 0 -- 0

a Rounding errors may occur; Tr = trace. Data from MN were not available.

b Other diseases were: Rhizoctonia root and stem rot in WI and Ontario, and green stem in IL.


Table 3 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states and Ontario during 1999a.

Diseases ND NE OH PA SD WI TOTAL Ontario
Anth racnose 0 29,159 0 0 406 1,676 31,242 0
Bacterial diseases 0 9,728 0 0 2,032 178 11,938 0
Brown spot 0 36,449 0 Tr 20,320 1,676 71,095 1,194
Brown stem rot 0 48,590 Tr Tr 4,064 33,452 262,509 4,775
Charcoal rot 0 965 Tr 0 0 5,029 556,997 4,775
Downy mildew 0 0 0 0 406 1,676 2,083 229
Frogeye leaf spot 0 0 0 0 0 0 6,325 0
Fusarium root rot 1,245 14,580 0 0 20,320 8,357 88,544 7,137
Other diseasesb 0 0 0 0 0 10,033 47,422 711
Phomopsis seed rot 0 2,438 0 0 8,128 3,353 48,997 1,194
Phytophthora rot 25,121 9,728 43,078 0 60,985 10,033 657,377 11,913
Pod and stem blight 0 9,728 0 1,321 20,320 5,029 275,996 1,194
Purple stain 0 4,851 0 0 4,064 0 86,817 0
Root-knot nematodes
& other nematodes
0 0 0 0 2,032 838 17,958 0
Sclerotinia stem rot 1,245 Tr Tr 1,321 40,665 25,095 68,555 7,137
Seed diseases 0 2,438 0 0 2,032 1,676 12,471 0
Seedling diseases 37,694 9,728 21,539 0 50,825 11,709 261,290 16,688
Southern blight 0 0 0 0 0 0 0 0
Soybean cyst nematode 0 14,580 129,261 0 101,651 16,713 4,132,250 71,501
Stem canker 0 9,728 Tr 0 4,064 5,029 68,605 7,137
Sudden death syndrome 0 0 Tr 0 0 178 482,625 1,676
Virus Tr 38,862 0 0 2,032 11,709 208,382 0

a Rounding errors may occur; Tr = trace. Data from MN were not available.

b Other diseases were: Rhizoctonia root and stem rot in WI and Ontario, and green stem in IL.



Table 4 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 2000a.

Diseases AL AR DE FL GA KY LA MD
Anthracnose 508 8,128 0 0 0 6,096 5,842 0
Bacterial diseases 0 254 0 0 0 1,270 0 0
Brown spot 0 508 0 0 0 2,540 508 0
Brown stem rot 0 0 0 0 0 0 0 0
Charcoal rot 1,524 102,870 0 254 254 18,034 17,272 0
Downy mildew 0 254 0 0 0 0 0 0
Frogeye leaf spot 254 1,270 0 0 508 0 0 0
Fusarium root rot 0 254 0 0 254 0 0 0
Other diseasesb 0 4,572 0 0 508 0 11,430 0
Phomopsis seed rot 0 254 0 0 508 18,034 11,430 0
Phytophthora rot 0 508 0 0 0 0 1,270 0
Pod and stem blight 0 8,128 0 0 0 3,556 11,430 0
Purple stain 0 11,430 0 0 0 0 23,114 0
Rhizoctonia aerial blight 0 1,270 0 0 0 0 508 0
Root-knot nematodes
& other nematodesc
1,016 36,576 0 0 4,064 0 11,938 5,334
Sclerotinia stem rot 0 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 762 41,148 0 254 508 2,540 508 0
Southern blight 0 508 0 0 254 0 508 0
Soybean cyst nematode 1,016 27,432 762 0 3,556 36,322 1,270 16,002
Stem canker 0 10,414 0 0 508 508 0 0
Sudden death syndrome 0 2,286 0 0 0 18,034 0 0
Virus 0 1,778 0 0 0 1,270 1,270 0

a Rounding errors may occur.

b Other diseases were: red crown rot caused by Cylindrocladium parasiticum in NC and GA; ozone in NC; green bean syndrome in AR and LA; target spot in LA; and Phymatotrichum root rot in TX.

c Other nematodes were: stubby root in VA; Columbia lance in NC and GA; lance in LA; lesion in AL; and Reniform in AL, AR, and NC.


Table 4 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 2000a.

Diseases MS NC OK SC TN TX VA TOTAL
Anthracnose 2,540 1,270 254 3,302 4,318 3,302 0 35,560
Bacterial diseases 0 0 0 0 0 0 0 1,524
Brown spot 0 1,270 0 254 2,540 254 0 7,874
Brown stem rot 0 0 0 0 0 0 0 0
Charcoal rot 125,730 3,556 2,794 254 10,160 11,176 0 293,878
Downy mildew 0 1,270 0 254 0 0 0 1,778
Frogeye leaf spot 0 508 0 254 8,382 4,572 0 15,748
Fusarium root rot 0 0 0 0 0 254 0 762
Other diseasesb 0 60,706 0 0 0 508 0 77,724
Phomopsis seed rot 0 0 508 0 0 2,286 4,826 37,846
Phytophthora rot 0 580 254 0 762 0 0 3,302
Pod and stem blight 5,080 4,826 2,032 2,540 0 1,016 1,016 39,624
Purple stain 1,016 1,016 762 762 0 1,016 0 39,116
Rhizoctonia aerial blight 2,540 0 0 0 0 0 0 4,318
Root-knot nematodes
& other nematodesc
0 15,748 254 6,350 2,540 254 3,302 87,376
Sclerotinia stem rot 0 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 0 0 1,016 254 12,700 508 2,286 62,484
Southern blight 0 1,016 0 4,064 1,778 254 0 8,382
Soybean cyst nematode 1,016 69,088 2,286 9,652 32,258 0 11,938 212,598
Stem canker 0 0 0 0 1,778 254 0 13,462
Sudden death syndrome 0 0 0 0 4,318 0 0 24,638
Virus 5,080 6,096 0 4,826 0 0 508 20,828

a Rounding errors may occur.

b Other diseases were: red crown rot caused by Cylindrocladium parasiticum in NC and GA; ozone in NC; green bean syndrome in AR and LA; target spot in LA; and Phymatotrichum root rot in TX.

c Other nematodes were: stubby root in VA; Columbia lance in NC and GA; lance in LA; lesion in AL; and Reniform in AL, AR, and NC.



Table 5 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states and Ontario during 2000a.

Diseases IA IL IN KS MI MN MO
Anthracnose 0 0 762 0 0 -- 0
Bacterial diseases 0 0 762 0 0 -- 0
Brown spot 0 147,091 1,524 152 0 -- 0
Brown stem rot Tr 73,533 113,081 0 0 -- 0
Charcoal rot 0 73,533 22,606 181,331 0 -- 95,961
Downy mildew 0 0 0 0 0 -- 0
Frogeye leaf spot 0 0 0 0 0 -- 4,801
Fusarium root rot 0 0 762 0 0 -- 11,989
Other diseasesb 0 0 0 15,113 0 -- 0
Phomopsis seed rot 70,282 73,533 3,759 0 0 -- 4,800
Phytophthora rot 70,282 147,091 263,881 16,612 Tr -- 47,981
Pod and stem blight 0 73,533 762 1,499 0 -- 0
Purple stain Tr 0 762 0 0 -- 0
Root-knot nematodes
& other nematodes
0 0 0 0 0 -- 4,800
Sclerotinia stem rot 70,282 0 3,759 0 Tr -- 0
Seed diseases 0 0 3,759 0 0 -- 0
Seedling diseases 0 147,091 30,150 7,087 0 -- 4,800
Southern blight 0 0 0 0 0 -- 0
Soybean cyst nematode 1,686,458 735,457 301,574 18,136 211,328 -- 143,916
Stem canker 0 14,707 3,759 762 0 -- 4,800
Sudden death syndrome 210,795 1,470,889 188,493 0 0 -- 23,978
Virus 281,076 73,533 7,544 0 0 -- 4,800

a Rounding errors may occur: Tr = trace. Losses in MN were not available.

b Other diseases were: Rhizoctonia root and stem rot in WI, and Alternaria leaf spot in KS.


Table 5 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states and Ontario during 2000a.

Diseases ND NE OH PA SD WI TOTAL Ontario
Anthracnose 0 0 0 0 0 1,702 2,464 0
Bacterial diseases 0 4,953 0 0 2,184 178 8,077 0
Brown spot 0 0 0 0 21,742 1,702 172,212 2,130
Brown stem rot 0 0 0 0 4,343 67,970 258,928 3,404
Charcoal rot 0 99,238 0 0 0 1,702 474,370 3,404
Downy mildew 0 0 0 14,224 0 1,702 15,926 229
Frogeye leaf spot 0 0 0 0 0 0 4,801 0
Fusarium root rot 8,585 0 5,182 0 4,343 8,763 39,624 6,782
Other diseasesb 0 0 0 0 0 1,702 16,815 0
Phomopsis seed rot 0 0 0 4,750 4,343 5,105 166,573 4,521
Phytophthora rot 68,605 49,606 259,105 0 65,227 12,751 1,001,141 18,110
Pod and stem blight 0 0 53,086 0 4,343 16,993 150,216 3,404
Purple stain 0 4,953 508 0 4,343 0 10,566 229
Root-knot nematodes
& other nematodes
0 0 0 0 0 838 5,639 0
Sclerotinia stem rot 1,727 24,816 0 23,698 86,970 33,985 245,237 20,371
Seed diseases 0 0 508 0 4,343 1,702 10,312 0
Seedling diseases 85,776 99,238 51,816 0 43,485 25,502 494,944 22,631
Southern blight 0 0 0 0 0 0 0 0
Soybean cyst nematode 0 49,606 77,724 0 152,171 16,993 3,393,364 67,894
Stem canker 0 0 508 0 21,742 5,105 51,384 5,664
Sudden death syndrome 0 0 508 0 0 5,105 1,899,768 6,782
Virus 0 49,632 448,945 0 43,485 16,993 926,008 229

a Rounding errors may occur; Tr = trace. Losses in MN were not available.

b Other diseases were: Rhizoctonia root and stem rot in WI, and Alternaria leaf spot in KS.



Table 6 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 2001a.

Diseases AL AR DE FL GA KY LA MD
Anthracnose 762 7,112 1,016 0 254 5,588 5,334 1,270
Bacterial diseases 0 254 0 0 0 254 0 0
Brown spot 0 254 0 0 0 14,224 508 0
Brown stem rot 0 0 0 0 0 254 0 0
Charcoal rot 762 129,286 4,318 254 0 28,194 5,334 1,270
Downy mildew 0 0 0 0 0 254 0 0
Frogeye leaf spot 762 2,286 0 0 254 2,794 508 0
Fusarium root rot 0 254 0 0 0 254 0 0
Other diseasesb 0 5,842 0 0 254 0 0 0
Phomopsis seed rot 0 18,796 1,016 0 0 14,224 10,922 2,286
Phytophthora rot 0 254 0 0 0 254 1,016 254
Pod and stem blight 0 15,748 0 254 0 2,794 5,334 1,270
Purple stain 254 2,794 0 0 0 254 10,922 2,286
Rhizoctonia aerial blight 0 7,112 0 0 0 0 8,128 1,778
Root-knot nematodes
& other nematodes
3,302 63,246 2,032 0 4,064 0 10,668 2,540
Sclerotinia stem rot 0 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 1,270 1,524 0 254 0 2,794 2,794 508
Southern blight 254 762 0 0 0 254 0 0
Soybean cyst nematode 1,270 139,446 6,350 0 3,048 42,418 2,794 508
Stem canker 0 3,810 0 0 508 254 0 0
Sudden death syndrome 254 3,810 0 0 0 7,112 0 0
Virus 0 254 0 0 0 2,794 1,016 254

a Rounding errors may occur.

b Other diseases were: ozone in NC; red crown rot caused by Cylindrocladium parasiticum in NC, SC and VA; and green stem in AR.


Table 6 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 2001a.

Diseases MS NC OK SC TN TX VA TOTAL
Anthracnose 9,652 0 254 1,524 92,964 1,016 0 126,746
Bacterial diseases 0 0 0 254 0 0 0 762
Brown spot 2,540 1,270 0 254 13,208 0 0 32,258
Brown stem rot 0 0 0 0 0 0 0 254
Charcoal rot 38,608 1,270 4,318 762 26,670 3,048 0 244,094
Downy mildew 0 508 0 254 0 0 0 1,016
Frogeye leaf spot 0 0 0 254 53,086 1,778 0 61,722
Fusarium root rot 0 0 0 0 0 0 0 508
Other diseasesb 0 62,992 0 1,524 0 0 762 71,374
Phomopsis seed rot 128,524 0 254 0 39,878 508 0 216,408
Phytophthora rot 0 1,270 508 0 0 0 0 3,556
Pod and stem blight 64,262 1,270 2,032 1,524 0 254 762 95,504
Purple stain 38,608 0 254 254 26,670 254 0 82,550
Rhizoctonia aerial blight 12,954 0 0 0 0 0 0 29,972
Root-knot nematodes
& other nematodes
0 20,320 0 25,908 2,540 0 4,318 138,938
Sclerotinia stem rot 0 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 25,654 0 1,270 254 33,274 0 4,318 73,914
Southern blight 0 1,270 0 1,778 0 0 0 4,318
Soybean cyst nematode 6,350 69,342 3,048 8,636 66,548 0 8,890 358,648
Stem canker 7,620 0 0 0 1,270 0 0 13,462
Sudden death syndrome 3,810 0 0 0 39,878 0 0 54,864
Virus 7,620 2,540 0 4,318 0 0 762 19,558

a Rounding errors may occur.

b Other diseases were: ozone in NC; red crown rot caused by Cylindrocladium parasiticum in NC; SC and VA; and green stem in AR.



Table 7 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states and Ontario during 2001a.

Diseases IA IL IN KS MI MN MO
Anthracnose 0 13,843 787 0 0 56,388 Tr
Bacterial diseases 0 0 787 0 0 0 0
Brown spot 0 13,843 15,824 0 0 0 0
Brown stem rot Tr 13,843 79,070 0 0 101,498 0
Charcoal rot 0 133,248 2,362 47,396 0 0 25,095
Downy mildew 0 0 0 0 0 0 0
Frogeye leaf spot Tr 0 Tr 0 0 0 0
Fusarium root rot 0 0 1,575 0 0 169,164 0
Other diseasesb 0 0 0 0 0 0 0
Phomopsis seed rot 0 13,843 3,937 0 0 0 Tr
Phytophthora rot 148,819 66,624 276,708 23,698 Tr 283,210 100,355
Pod and stem blight 520,903 13,843 787 Tr 0 0 TrTrTrT
Purple stain 0 0 787 Tr 0 0 0
Root-knot nematodes
& other nematodes
0 0 0 Tr 0 0 2,489
Sclerotinia stem rot Tr 13,843 787 Tr Tr 11,278 0
Seed diseases 0 0 3,937 0 0 0 0
Seedling diseases 297,663 13,843 3,175 23,698 0 56,388 50,190
Southern blight 0 0 0 0 0 0 0
Soybean cyst nematode 1,500,000 666,217 316,484 47,396 85,420 394,716 100,355
Stem canker 0 13,843 2,362 1,194 0 56,388 0
Sudden death syndrome 148,819 199,873 181,839 Tr 0 0 5,029
Virus 223,241 13,843 7,899 7,112 0 0 5,029

a Rounding errors may occur; Tr = trace.

b Other diseases were: Rhizoctonia root and stem rot in WI.


Table 7 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states and Ontario during 2001a.

Diseases ND NE OH PA SD WI TOTAL Ontario
Anthracnose 0 0 0 0 Tr 1,778 72,796 0
Bacterial diseases 0 5,918 0 0 1,956 178 8,839 0
Brown spot 0 0 Tr 0 3,886 1,778 35,331 965
Brown stem rot 0 0 55,448 0 3,886 61,900 315,645 610
Charcoal rot 0 5,918 0 0 19,482 1,778 235,279 1,829
Downy mildew 0 0 0 0 Tr 1,778 1,778 610
Frogeye leaf spot 0 0 0 0 0 178 178 0
Fusarium root rot 7,874 11,811 55,448 0 3,886 8,839 258,597 1,219
Other diseasesb 0 0 0 0 0 1,778 1,778 0
Phomopsis seed rot 0 17,729 Tr 0 3,886 8,839 48,234 6,096
Phytophthora rot 78,791 35,458 277,292 0 77,902 17,678 1,386,535 6,096
Pod and stem blight 0 5,918 Tr 0 1,956 17,678 561,085 1,219
Purple stain 0 17,729 0 0 1,956 0 20,472 127
Root-knot nematodes
& other nematodes
0 0 0 0 0 0 2,489 0
Sclerotinia stem rot 0 0 Tr 0 19,482 17,678 63,068 0
Seed diseases 0 0 0 0 3,886 1,778 9,601 6,096
Seedling diseases 59,106 82,753 110,922 0 38,964 35,382 772,084 24,333
Southern blight 0 0 0 0 0 0 0 0
Soybean cyst nematode 0 17,729 277,292 0 136,347 26,518 3,568,474 36,525
Stem canker 0 0 Tr 0 19,482 8,839 102,108 2,438
Sudden death syndrome 0 0 Tr 0 0 3,531 539,091 3,658
Virus 1,981 47,295 Tr 0 38,964 35,382 380,746 127

a Rounding errors may occur; Tr = trace.

b Other diseases were: Rhizoctonia root and stem rot in WI.



Table 8 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 2002a.

Diseases AL AR DE FL GA KY LA MD
Anthracnose 1,270 22,603 254 ---- 254 2,286 6,095 1,270
Bacterial diseases 0 254 0 ---- 0 0 0 0
Brown spot 0 254 0 ---- 0 5,587 0 0
Brown stem rot 0 0 0 ---- 0 0 0 0
Charcoal rot 508 134,857 1,016 ---- 254 27,937 6,095 1,270
Downy mildew 254 0 0 ---- 0 0 0 0
Frogeye leaf spot 0 11,429 0 ---- 254 3,302 1,270 0
Fusarium root rot 0 254 0 ---- 0 0 0 0
Other diseasesb 0 0 0 ---- 508 0 0 0
Phomopsis seed rot 8,381 29,968 508 ---- 254 16,762 12,191 762
Phytophthora rot 0 254 0 ---- 0 0 6,095 0
Pod and stem blight 3,556 29,968 0 ---- 254 3,302 12,191 0
Purple stain 3,556 6,095 0 ---- 0 254 18,286 0
Rhizoctonia aerial blight 0 0 0 ---- 0 0 12,191 0
Root-knot nematode
& other nematodes
1,270 56,889 1,016 ---- 3,556 0 12,698 762
Sclerotinia stem rot 0 0 0 ---- 0 0 0 0
Seed diseases 0 0 0 ---- 0 0 0 0
Seedling diseases 0 1,016 254 ---- 0 3,302 254 0
Southern blight 0 1,016 0 ---- 0 254 0 0
Soybean cyst nematode 508 104,889 3,302 ---- 2,794 39,111 1,270 5,587
Stem canker 6,095 6,095 0 ---- 508 0 0 0
Sudden death syndrome 0 3,302 0 ---- 0 0 0 0
Virus 0 254 0 ---- 0 508 1,270 0

a Rounding errors may occur; losses in FL were not available.

b Other diseases were: red crown rot caused by Cylindrocladium parasiticum in NC, GA, and VA;, ozone in NC; green bean syndrome in AR and LA; target spot in LA; and Phymatotrichum root rot in TX.


Table 8 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 15 southern states during 2002a.

Diseases MS NC OK SC TN TX VA TOTAL
Anthracnose 15,492 254 254 2,286 38,349 4,064 1,270 96,001
Bacterial diseases 0 0 254 508 0 254 0 1,270
Brown spot 3,048 0 0 0 25,651 508 0 35,048
Brown stem rot 0 0 0 0 0 0 0 0
Charcoal rot 30,984 1,016 1,778 0 51,302 10,159 508 267,684
Downy mildew 0 0 0 0 0 0 0 254
Frogeye leaf spot 15,492 0 254 0 99,810 4,064 0 135,875
Fusarium root rot 0 0 0 0 0 508 0 762
Other diseasesb 0 47,238 0 508 0 0 0 48,254
Phomopsis seed rot 123,683 9,397 1,016 2,286 25,651 4,064 0 234,923
Phytophthora rot 0 1,016 0 0 0 254 0 7,619
Pod and stem blight 54,095 4,825 1,016 1,270 0 1,016 508 112,001
Purple stain 30,984 2,794 254 0 19,302 4,064 508 86,097
Rhizoctonia aerial blight 11,683 0 0 0 0 508 0 24,382
Root-knot nematode
& other nematodes
0 15,238 254 18,794 0 254 1,270 112,001
Sclerotinia stem rot 0 0 0 0 0 0 0 0
Seed diseases 0 0 0 0 0 0 0 0
Seedling diseases 23,111 0 762 254 19,302 1,016 2,540 51,811
Southern blight 0 1,016 0 1,778 0 508 0 4,572
Soybean cyst nematode 1,524 47,238 1,016 4,571 64,000 0 2,540 278,350
Stem canker 4,571 0 0 0 1,270 254 0 18,793
Sudden death syndrome 6,095 0 0 0 25,651 508 0 35,556
Virus 0 1,778 0 4,571 0 508 508 9,397

a Rounding errors may occur, losses in FL were not available.

b Other diseases were: red crown rot caused by Cylindrocladium parasiticum in NC, GA, and VA;, ozone in NC; green bean syndrome in AR and LA; target spot in LA; and Phymatotrichum root rot in TX.



Table 9 (Part I). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states during 2002a.

Diseases IA IL IN KS MI MN MO
Anthracnose 0 0 660 0 0 50,794 406
Bacterial diseases 0 0 660 0 0 12,698 0
Brown spot 0 12,749 6,578 0 0 0 0
Brown stem rot 0 12,749 6,578 0 0 63,492 0
Charcoal rot 0 191,086 19,708 166,222 0 0 61,816
Downy mildew 0 0 0 0 0 0 0
Frogeye leaf spot 14,324 12,749 13,156 0 0 0 406
Fusarium root rot 0 0 1,321 0 0 317,460 4,114
Other diseasesb 0 0 0 0 0 0 0
Phomopsis seed rot 0 0 3,276 Tr 0 0 406
Phytophthora rot Tr 254,781 197,156 18,464 Tr 228,571 82,438
Pod and stem blight 0 25,473 660 1,854 0 0 0
Purple stain 14,324 12,749 660 0 0 0 406
Root-knot nematodes
& other nematodes
0 12,749 Tr 0 0 0 51
Sclerotinia stem rot 0 12,749 660 0 Tr 25,397 0
Seed diseases 0 0 3,276 0 0 0 0
Seedling diseases Tr 63,695 32,864 46,171 0 126,984 4,114
Southern blight 0 0 0 0 0 0 0
Soybean cyst nematode 1,146,718 891,733 262,857 27,708 140,927 380,952 61,816
Stem canker 0 12,749 660 Tr 0 63,492 0
Sudden death syndrome 215,010 382,171 85,867 Tr 0 0 4,114
Virus 501,689 63,695 7,898 1,854 0 0 4,114

a Rounding errors may occur; Tr = trace.

b Other diseases were: Rhizoctonia root and stem rot in WI.


Table 9 (Part II). Estimated reduction of soybean yields in metric tons due to diseases for 13 northern states during 2002a.

Diseases ND NE OH PA SD WI Total Ontario
Anthracnose 0 0 0 4,013 Tr 8,762 64,635 0
Bacterial diseases 0 483 0 0 1,718 177 15,796 0
Brown spot 0 0 0 4,013 1,778 1,752 26,870 990
Brown stem rot 0 48,076 4,368 0 17,702 35,073 188,038 1,397
Charcoal rot 0 48,076 14,857 16,025 17,702 1,752 537,244 2,971
Downy mildew 0 0 0 0 Tr 1,752 1,752 990
Frogeye leaf spot 0 51 0 0 0 1,752 42,438 203
Fusarium root rot 11,073 4,800 43,556 0 3,530 8,762 394,616 3,962
Other diseasesb 0 0 0 0 0 8,762 8,762 0
Phomopsis seed rot 0 483 0 100,216 3,530 8,762 116,673 7,924
Phytophthora rot 88,660 965 217,778 0 53,079 17,549 1,159,441 9,905
Pod and stem blight 0 483 0 0 1,778 8,762 39,010 3,962
Purple stain 0 48,076 0 20,038 1,778 178 98,209 203
Root-knot nematodes
& other nematodes
0 0 0 0 1,778 178 14,756 0
Sclerotinia stem rot 0 51 0 0 17,702 17,549 74,108 990
Seed diseases 0 0 0 0 3,530 1,752 8,558 990
Seedling diseases 44,317 33,651 87,111 8,018 35,378 17,549 502,852 49,549
Southern blight 0 0 0 0 0 0 0 0
Soybean cyst nematode 0 43,276 217,778 0 141,562 35,073 3,350,400 65,397
Stem canker 0 0 0 0 3,530 8,762 89,193 5,943
Sudden death syndrome 0 0 4,368 0 0 1,752 693,282 7,924
Virus 0 43,276 4,368 4,013 70,781 52,622 754,310 1,981

a Rounding errors may occur; Tr = trace.

b Other diseases were: Rhizoctonia root and stem rot in WI.



Table 10. Estimated reduction of Ontario soybean yields in metric tons
due to diseases during 1999, 2000, 2001 and 2002.

Diseases 1999 2000 2001 2002
Anthracnose 0 0 0 0
Bacterial diseases 0 0 0 0
Brown spot 1,194 2,130 965 990
Brown stem rot 4,775 3,404 610 1,397
Charcoal rot 4,775 3,404 1,829 2,971
Downy mildew 229 229 610 990
Frogeye leaf spot 0 0 0 203
Fusarium root rot 7,137 6,782 1,219 3,962
Other diseases 711 0 0 0
Phomopsis seed rot 1,194 4,521 6,096 7,924
Phytophthora rot 11,913 18,110 6,096 9,905
Pod and stem blight 1,194 3,404 1,219 3,962
Purple stain 0 229 127 203
Rhizoctonia aerial blight 0 0 0 0
Root-knot nematodes
& other nematodes
0 0 0 0
Sclerotinia stem rot 7,137 20,371 0 990
Seed diseases 0 0 6,096 990
Seedling diseases 16,688 22,631 24,333 49,549
Southern blight 0 0 0 0
Soybean cyst nematode 71,501 67,894 36,525 65,397
Stem canker 7,137 5,664 2,438 5,943
Sudden death syndrome 1,676 6,782 3,658 7,924
Virus 0 229 127 1,981
Total 137,261 165,784 91,948 165,281


Table 11. Estimated reduction of US soybean yields in metric tons due to diseases during 1999, 2000, 2001, and 2002.

Diseases 1999 2000 2001 2002
Anthracnose 77,216 38,024 199,542 160,636
Bacterial diseases 12,192 9,601 9,601 17,066
Brown spot 74,905 180,086 67,589 61,918
Brown stem rot 262,509 258,928 315,899 188,038
Charcoal rot 1,025,881 768,248 479,373 804,928
Downy mildew 3,099 17,704 2,794 2,006
Frogeye leaf spot 18,263 20,549 61,900 178,313
Fusarium root rot 89,306 40,386 259,105 395,378
Other diseases 49,632 94,539 73,152 57,016
Phomopsis seed rot 64,745 204,419 264,642 351,596
Phytophthora rot 663,981 1,004,443 1,390,091 1,167,060
Pod and stem blight 354,482 189,840 656,589 151,011
Purple stain 128,727 49,682 103,022 184,306
Rhizoctonia aerial blight 15,748 4,318 29,972 24,382
Root-knot nematodes
& other nematodes
113,462 93,015 141,427 126,757
Sclerotinia stem rot 68,555 245,237 63,068 74,108
Seed diseases 12,471 10,312 9,601 8,558
Seedling diseases 312,852 557,428 845,998 554,663
Southern blight 6,604 8,382 4,318 4,572
Soybean cyst nematode 4,299,382 3,605,962 3,927,122 3,628,750
Stem canker 76,225 64,846 115,570 107,986
Sudden death syndrome 488,213 1,924,406 593,955 728,838
Virus 227,178 946,836 400,304 763,707
Total 8,445,628 10,337,191 10,014,634 9,694,355