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2003 Soybean Disease And Future Management, X. B. Yang Dec 2003

2003 Soybean Disease And Future Management, X. B. Yang

Integrated Crop Management News

Diseases are an important factor in our management to stabilize soybean yield. Weather in a growing season dictates the types of disease outbreaks. In the past 10 years, outbreaks of diseases have varied from season to season and 2003 was no exception. Early in the season, rainfall was excessive and some fields were flooded. There were reports on occurrence of Phytophthora and seedling diseases in Iowa. Cool and wet early summer was also favorable to white mold infections and the disease appeared in eastern Iowa with reported infections over 70 percent diseased plants in some fields.


Concerns Related To Soybean Seed Quality, X. B. Yang Oct 2003

Concerns Related To Soybean Seed Quality, X. B. Yang

Integrated Crop Management News

During this growing season soybean Asian aphid and charcoal rot were prevalent in Iowa and caused severe damage in many soybean fields. Charcoal rot is reportedly a seedborne disease. Asian aphids transmit a seedborne disease, soybean mosaic virus (SMV). Since these two diseases are considered seedborne, seed quality related to these two diseases has been a concern, especially for SMV.


Charcoal Rot -- A Dry Weather Disease, X. B. Yang, Shrishail S. Navi Oct 2003

Charcoal Rot -- A Dry Weather Disease, X. B. Yang, Shrishail S. Navi

Integrated Crop Management News

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.


Charcoal Rot -- A Disease New To Iowa Farmers, X. B. Yang, Shrishail S. Navi, Palle Pedersen Sep 2003

Charcoal Rot -- A Disease New To Iowa Farmers, X. B. Yang, Shrishail S. Navi, Palle Pedersen

Integrated Crop Management News

August was the driest month on record in Iowa with most of the state being in severe drought. Because of these extreme environmental conditions a disease new to soybean producers has been prevalent in Iowa soybean fields this year. The disease is charcoal rot, a yield robber from the south.


Sds Information Available On Cd-Rom From Isu Crop Adviser Institute, Brent Brueland, X. B. Yang Aug 2003

Sds Information Available On Cd-Rom From Isu Crop Adviser Institute, Brent Brueland, X. B. Yang

Integrated Crop Management News

The Iowa State University Crop Adviser Institute (CAI) recently completed a new interactive course module on CD-ROM, entitled Sudden Death Syndrome of Soybean, authored by Iowa State University Extension plant pathologist X.B. Yang, and Brent Brueland, ISU Agronomy Department. This module describes the soybean fungus Fusarium solani f.sp. glycines and provides details on the sudden death syndrome (SDS) disease's

  • life cycle;
  • identification;
  • potential for damage;
  • current geographical distribution; and
  • SDS management.

The CD contains many high-quality photographs, graphics of latest research results, and interactive segments designed to enhance the learning experience.


Brown Stem Rot Or Fusarium Wilt?, X. B. Yang Aug 2003

Brown Stem Rot Or Fusarium Wilt?, X. B. Yang

Integrated Crop Management News

Different seasons have different diseases and therefore, different production questions have to be addressed. In this cool and wet summer, our Plant Disease Clinic received a number of samples with disease symptoms that challenged both agronomists who are doing field calls and plant pathologists who are involved with the diagnosis. The first sample (photo images) came July 18th from Steve Barnhart, regional agronomist of Agriliance.


Soybean Brown Spot And Bacterial Blight, X. B. Yang Jul 2003

Soybean Brown Spot And Bacterial Blight, X. B. Yang

Integrated Crop Management News

The excessive rains and cool temperatures during early summer created conditions that favor certain diseases. Besides iron chlorosis, growers and agronomists from co-ops report occurrence of Phytopathora, Fusarium wilt, brown stem rot, and soybean brown spot, which is prevalent in many soybean fields. This article focuses on brown spot.


Soybean Root Rot In 2003, X. B. Yang Jul 2003

Soybean Root Rot In 2003, X. B. Yang

Integrated Crop Management News

Phone calls and samples of soybean root rot infection have been spurred by the recent extensive rainfall. Wet soil conditions are ideal for some soilborne fungi to infect soybean roots. In many soybean fields, plant leaves are turning yellow, an indication of iron chlorosis, which is often associated with fungal root rot. In fields where plants experienced hail injury, root rot problems can be pronounced. In this article, I discuss fungal root rot diseases.


Scouting For Soybean Seedling Diseases In 2003, X. B. Yang May 2003

Scouting For Soybean Seedling Diseases In 2003, X. B. Yang

Integrated Crop Management News

In Iowa, every planting season has different seedling diseases. In the last two planting seasons, there were fewer spring rains compared with this year, and seedling diseases were not a problem. Because of the frequent spring rains this year, we have less early-planted soybean and more fields planted in mid-May or later. Reports and samples of seedling diseases also are later this year.


Phytophthora Damping-Off In A Rainy Spring, X. B. Yang May 2003

Phytophthora Damping-Off In A Rainy Spring, X. B. Yang

Integrated Crop Management News

We have had plenty of rainfall across Iowa since late April. Frequent rainfall has slowed soybean planting for the past 2 weeks. Based on recent reports from Iowa State University field crop specialists, only about 10 percent of soybean are planted, which is much less than what we had in the ground at this time during the last two growing seasons.


Scouting Alfalfa Diseases In Spring, X. B. Yang May 2003

Scouting Alfalfa Diseases In Spring, X. B. Yang

Integrated Crop Management News

So far this spring, we have received considerable precipitation. Frequent rainfalls in spring are favorable for the development of foliar diseases on alfalfa. It is time to check for these diseases, especially if more rain occurs over the next 2 weeks. Knowing the level of alfalfa disease in early May helps in making management decisions. High levels of foliar diseases in May can cause early defoliation before the first cutting. Poor growth in spring due to disease problems also may affect alfalfa growth in summer and fall.


Recent Bean Leaf Beetle And Bean Pod Mottle Virus Research, Jeffrey D. Bradshaw, Marlin E. Rice, John H. Hill Apr 2003

Recent Bean Leaf Beetle And Bean Pod Mottle Virus Research, Jeffrey D. Bradshaw, Marlin E. Rice, John H. Hill

Integrated Crop Management News

Soybean growers face a dilemma when considering management options for bean leaf beetles and bean pod mottle virus. Rayda Krell recently completed a research program at Iowa State University that focused on immediate solutions for this pest problem. This article summarizes her research from which we suggest some short-term management options.


Management Decisions For Bean Leaf Beetles And Bean Pod Mottle Virus, Jeffrey D. Bradshaw, Marlin E. Rice, John H. Hill Apr 2003

Management Decisions For Bean Leaf Beetles And Bean Pod Mottle Virus, Jeffrey D. Bradshaw, Marlin E. Rice, John H. Hill

Integrated Crop Management News

Yogi Berra said, "If you come to a fork in the road, take it." Many soybean producers will be at that fork in a couple of weeks, trying to decide whether or not to spray overwintered bean leaf beetles, and determining how to manage bean pod mottle virus. The dilemma is that some overwintered bean leaf beetles may transmit bean pod mottle virus and not knowing where in Iowa the problem is most likely to occur, what percentage of beetles are transmitting the virus, or when to spray can greatly complicate management decisions.


There's Still Time To Test Fields For Scn, Gregory L. Tylka Apr 2003

There's Still Time To Test Fields For Scn, Gregory L. Tylka

Integrated Crop Management News

There's still time this spring before planting to check fields for the presence of the soybean cyst nematode (SCN). This nematode is widespread throughout Iowa, but infestations can go unnoticed because obvious aboveground symptoms may not be visible for many years after the introduction of the pest into the field. Early detection of SCN infestations when population densities (numbers) are low is very important because it is much easier to keep low population densities of SCN in check than to decrease high population densities.


New Insights On Early Planting And Sds, X. B. Yang, Shrishail S. Navi Apr 2003

New Insights On Early Planting And Sds, X. B. Yang, Shrishail S. Navi

Integrated Crop Management News

Since SDS was first reported in Iowa in 1994, soybean growers and agronomists who have experience with this disease have observed that it seems more severe in early planted soybean. Surveys completed by participants of extension winter meetings in Iowa also indicated that fields showing severe defoliation in the fall are likely to have been planted before May. Last year's warm spring and early planting may have contributed to the high prevalence of SDS in the 2002 growing season. Rarely, there are cases of severe SDS in fields planted after May 15. Research in Missouri confirms that the disease ...


Soybean Seed Treatments In 2003, X. B. Yang Mar 2003

Soybean Seed Treatments In 2003, X. B. Yang

Integrated Crop Management News

As planting season approaches, it is time to consider seed treatment. Damping-off diseases are a major concern for early-planted soybean. Because more and more growers are planting early, they are interested in using seed treatments to promote good stand establishment. This article describes how and when to use seed treatment.


Sds Management For 2003 Season, X. B. Yang Jan 2003

Sds Management For 2003 Season, X. B. Yang

Integrated Crop Management News

In extension winter meetings, one of the major discussion topics on soybean diseases was sudden death syndrome (SDS) management because this disease was widespread during the past growing season. Many producers are concerned about the risk of this disease in the 2003 growing season and have asked about effective management practices.


Using Seed And Foliar Insecticides To Control Corn Flea Beetles And Stewart's Disease Of Corn, Forrest W. Nutter Jr., Blucher Menelas, Paul Esker Jan 2003

Using Seed And Foliar Insecticides To Control Corn Flea Beetles And Stewart's Disease Of Corn, Forrest W. Nutter Jr., Blucher Menelas, Paul Esker

Iowa State Research Farm Progress Reports

Stewart's disease of corn, caused by Pantoea (Erwinia) stewartii has significant economic implications for sweet and seed corn producers. These problems stem from phytosanitary regulations put in place by many countries to prevent the introduction of this pathogen into their countries. Growers or seed producers have to perform costly tests on seeds from fields where P. stewartii was found to occur in order to export the seed. Foliar insecticides have been used to reduce corn flea beetle populations during the growing season as a means to reduce the risk of Stewart's disease of corn. This management practice, however ...


Sampling For Corn Flea Beetles Using Yellow Sticky Cards Placed At Different Heights And Orientations, Paul Esker, Forrest W. Nutter Jr. Jan 2003

Sampling For Corn Flea Beetles Using Yellow Sticky Cards Placed At Different Heights And Orientations, Paul Esker, Forrest W. Nutter Jr.

Iowa State Research Farm Progress Reports

When developing reliable disease management programs, it is important to ascertain the most reliable method to quantify the potential sources of inoculum for an epidemic. In the Stewart’s disease of corn pathosystem, the primary source of inoculum is the corn flea beetle (Chaetocnema pulicaria). This is because the transmission and survival of Pantoea stewartii, the causative organism, occurs by this vector. Management for Stewart’s disease focuses on reducing feeding by the corn flea beetle, thereby reducing transmission of the bacterium. Although there are management protocols currently in place that use visual counts for corn flea beetles to help ...


Trapping And Other Strategies For Cucumber Beetle Management, Mark L. Gleason, Sara Jane Helland, Bernard J. Havlovic Jan 2003

Trapping And Other Strategies For Cucumber Beetle Management, Mark L. Gleason, Sara Jane Helland, Bernard J. Havlovic

Iowa State Research Farm Progress Reports

Spotted and striped cucumber beetles vector a bacterium that causes wilt in cucurbits (plants in the gourd family). These beetles are the major pest of muskmelons in Iowa. We investigated the success of a prototype Trecé brand trap and bait system, soon to be OMRI-approved (Organic Materials Review Institute), that chemically lures beetles to insecticide-treated bait inside a trap some distance away from the muskmelon crop. We also tested the success of Reemay fabric row covers, clear slitted plastic row covers, and BioYield seed treatment. BioYield is a seed inoculant that includes a variety of plant growth-promoting rhizobacteria.


Effect Of Seed Soybean Treatments On Seed Emergence And Yield, Peter Lundeen, Xiao-Bing Yang Jan 2003

Effect Of Seed Soybean Treatments On Seed Emergence And Yield, Peter Lundeen, Xiao-Bing Yang

Iowa State Research Farm Progress Reports

The purpose of this study was to evaluate soybean seed treatments on disease pressure. There have been experimental plots for seed treatment evaluation at the McNay Research Farm for the last three years. The McNay farm was selected for seed treatment experimental plots because it exhibited a high level of phytophthora damping off the spring of 1999. The objective of this study is to determine the effect of different seed treatments on seedling diseases under high disease pressure as expressed by stand establishment, plant vigor, and harvest yield.


Evaluation Of Soybean Varieties Resistant To Soybean Cyst Nematode In Southeast Iowa In 2002, Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett Jan 2003

Evaluation Of Soybean Varieties Resistant To Soybean Cyst Nematode In Southeast Iowa In 2002, Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett

Iowa State Research Farm Progress Reports

The use of resistant soybean varieties is a very effective strategy for managing soybean cyst nematode (SCN), and numerous SCN-resistant soybean varieties are available for Iowa soybean growers. Each year, public and private SCN-resistant soybean varieties are evaluated in SCN-infested and noninfested fields throughout Iowa by Iowa State University personnel. The research described in this report was performed to assess the agronomic performance of maturity groups (MG) II and III SCN-resistant soybean varieties and to determine the effects of the varieties on SCN population densities.


Evaluation Of Soybean Varieties Resistant To Soybean Cyst Nematode In Northern Iowa In 2002, Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett Jan 2003

Evaluation Of Soybean Varieties Resistant To Soybean Cyst Nematode In Northern Iowa In 2002, Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett

Iowa State Research Farm Progress Reports

The use of resistant soybean varieties is a very effective strategy for managing soybean cyst nematode (SCN), and numerous SCN-resistant soybean varieties are available for Iowa soybean growers. Each year, Iowa State University personnel evaluate public and private SCNresistant soybean varieties in SCN-infested fields throughout Iowa. The research described in this report was performed to assess the agronomic performance of maturity group (MG) I and II SCN-resistant soybean varieties and to determine the effects of the varieties on SCN population densities.


Monitoring Changes In Corn Flea Beetle Populations, 1999 To 2002, Paul Esker, Forrest W. Nutter Jr. Jan 2003

Monitoring Changes In Corn Flea Beetle Populations, 1999 To 2002, Paul Esker, Forrest W. Nutter Jr.

Iowa State Research Farm Progress Reports

Stewart's disease of corn, caused by the bacterium Pantoea (Erwinia) stewartii, is an extremely important disease for seed and sweet corn producers. Economic losses can be substantial for both producers. In the seed corn industry, zero tolerance phytosanitary regulations greatly limit the ability of seed corn to be exported from fields where Stewart's disease has been found. One area of research that has been limited in regard to Stewart’s disease is the population dynamics of the corn flea beetle (Chaetocnema pulicaria) vector. The corn flea beetle is the primary mode for acquiring and transmitting P. stewartii, as ...