Managing soybean sudden death syndrome and white mold

The cool 2009 growing season resulted in a challenging disease management year for soybean growers. The long wet planting season followed by a record cool July was ideal for disease occurrence. It was the first time that two soybean diseases, sudden death syndrome (SDS) and soybean white mold, were wide spread in the same season in Iowa, as well other states. In August, SDS showed up almost in every area in Iowa with some regions having high intensity. Large patches of soybean with SDS symptom were obvious from south to north. Into late August, white mold gained attention as producers knew from their previous harvest experience that this disease affects yield. This year white mold was so wide spread that agronomists in southern Iowa reported the observations of this disease in many soybean fields. In northern Iowa, patches of soybean killed by this disease were so obvious that I found them in nearly every soybean field while attending a field day. Prior to 2009, the highest loss from white mold in my memory was about $32,000 for a farm. This year, a farmer told me he estimated a loss of$40,000 by this disease from his farm

Strategies for Management of Soybean Sudden Death Syndrome and White Mold

Soybean sudden death syndrome (SDS) caused by Fusarium solani f. sp. glycines and soybean white mold caused Sclerotinia sclerotiorum were two of the most prevalent diseases in 2006. The two diseases have become even year production problems for some producers. This workshop will review results of the latest studies from the past two years and discuss management strategies for the two diseases. The SDS has been recognized as a major disease of soybean (Glycine max (L.) Merrill) in the southern United States for nearly three decades. In 1995 Scherm and Yang using computer model predicted that the disease would become an important disease in North Central region. In the past 10 years SDS has becom prevalent and severe in northern soybean production areas and reduces soybean yield significantly. SDS is an early to late season disease of soybean. This year SDS has been observed in most parts of Iowa towards mid September. There is concern among producers in the north central region, due to noticeable expansion in geographical array of SDS, wide spread damage in the field and the associated potential yield losses. Yield loss due to SDS in the top 10 soybean producing countries varies from 2 x103 in Canada to 9 x105 metric tons in the United States (Wrather, et al., 2001). The SDS generally occur in fields where yield potentials are high and yield losses up to 50% have been observed in Arkansas (Rupe, et al 1989). The SDS was first found in Iowa, in experimental plots in 1993 (Yang and Rizvi 1994). However, SDS was first noticed in Arkansas in 1971 as disease of unknown cause. Later it was reported from Tennessee, Missouri, and Mississippi in 1984, from Illinois, Kentucky, Kansas and Indiana in 1985 (Rupe et al 1989, Wylie, T.D. 1988) and an epidemic (46% of the soybean fields) in 1993 in east -central Illinois (Hartman, et al 1995). The SDS has been reported in 2004 from Nebraska (Ziems, et al 2006), and from Argentina (Scandiani, et al 2004). The yield damage caused by SDS and white mold are comparable now. Like SDS, soybean white mold also is more prevalent in fields with high yielding potential

Stop SDS: Prioritizing Management Approaches That Best Fit Your Fields

Sudden death syndrome (SDS) is a mid- to late-season, soil borne disease that occurs primarily in soybean fields with high yield potential. First observed in Arkansas in 1971, SDS now causes significant losses in Midwestern states such as Illinois and Indiana and is considered the most important fungal disease in causing yield loss in the North Central Region. The disease was first noticed in Iowa in 1993. Now the disease has been found from border to border in Iowa. It occurs annually in eastern Iowa and epidemics occur frequently in recent years. Yield losses due to SDS vary widely. SDS may cause premature defoliation in the fall resulting in nearly total yield loss in all or portions of the severely affected fields, depending on the weather in the growing season. The disease causes foliar symptoms, resulting in pod abortion and yield loss up to 70% in severe cases

Use of Fungicides to Control Soybean Foliar Diseases in Iowa: A 6-Year Summary

Prior to 2004, foliar diseases were not a concern in soybean production in Iowa and much of the north central region, except for seed production. Since the report of Asian soybean rust, caused by Phakopsora pachyrhizhi, in South America in 2001 and then in the United States in 2004, fungicide applications became of interest to some producers. Interest has increased recently as soybean prices increased. The use of fungicides to control soybean foliar diseases has been a hot topic. Surveys of the literature show a disagreement among researchers, university extension recommendations and industry applications

Management of Urd Bean Leaf Crinkle Virus in Urd Bean (Vigna Mungo L. Hepper)

Six plant extracts viz , Mirabtlis jalapa, Carthamus roseus. Datura metal, Bougainvitlea spectabilis, Boerhaavia diffusa and Azadirachta indica recorded maximum reduction in the incidence of urd bean leaf crinkle virus (ULCV) in urd bean crops at field level Among the antiphytovirat chemicals tested, DHT reduced the transmission to the maximum extent and increased the incubation period of virus in the urd bean plant Fresh buttermilk was significantly superior to fermented buttermilk in reducing the disease spread and increasing the incubation period of the virus in the plant. Casein was found effective in reducing the per cent transmission and increased the incubation period of the virus. Raising barrier crops viz maize, sorghum and pearl millet were equally effective in reducing the spread of the disease in field Spraying of DHT at two intervals. 7 and 22 DAS was found effective in reducing the disease spread when compared with Thuja, buttermilk, ivf jalapa and neem oil

Charcoal rot -- a dry weather disease

In the last issue of the ICM Newsletter, we reported that charcoal rot, a drought-related soybean disease, was prevalent in Iowa late this summer, causing premature death of soybeans. We briefly discussed identification and scouting methods. In this article, we address management issues and provide more information on identifying this disease in fall