AMES, Iowa - In past years, sudden death syndrome (SDS) has appeared during the last week of July or the first week of August in Iowa. Therefore, researchers at Iowa State University (ISU) anticipate symptoms of SDS will begin appearing in the state with the next couple of weeks. Although researchers do not expect SDS to be as widespread or as severe as the 2010 growing season, there have been some counties within the state that have received higher-than-normal precipitation. Scientists expect the risk of SDS in these counties to be higher since disease development is favored by wet conditions.

Begin scouting for SDS soon
The first symptoms of the disease are usually found on more compacted and low areas of the field. First symptoms are seen on the leaves of infected plants as scattered, yellow spots between leaf veins. Large sections of leaf tissue between veins turn yellow as spots grow together. These yellow blotches soon turn brown, but the veins remain green. Eventually, the leaves die and drop, but the petioles remain on the stem. Infected plants are also easily pulled from the soil because the roots are rotted. When split lengthwise with a knife, the internal tissue of the main or tap root will be gray to reddish brown, not healthy white.
ISU researchers emphasize that, while there are no in-season management options for SDS, scouting is still important for several reasons. 

• First, this is a good time to evaluate soybean varieties for resistance to SDS. Growing resistant varieties, or avoiding very susceptible varieties, is the most effective way to reduce losses to SDS.
• Also, identifying fields or parts of fields with SDS can help with future management practices. These management tactics include reducing soil compaction since the disease has been associated with compacted soil; planting fields with a history of SDS towards the end of a planting schedule when soils may be warmer and drier; and testing for the presence of soybean cyst nematodes.
• Soybean cyst nematode (SCN) is usually, but not always, associated with SDS and may increase its severity, especially in varieties that are SCN-susceptible. Therefore, management practices to reduce SCN populations, including SCN-resistant variety selection and preventing the spread of soil from field to field, may delay onset and spread of SDS.

"Several Iowa State University pathologists and agronomists continue research to improve our understanding the biology of the fungus that causes SDS and develop improved management options for the disease," said Alison Robertson, ISU Extension plant pathologist. "The ISU soybean breeding program continues to develop and release germplasm with improved resistance to SDS that is available to all private soybean breeding companies. ISU scientists collaborate with scientists at other universities."

Most of the SDS research at ISU is funded by soybean checkoff dollars from state, regional and national organizations, namely the Iowa Soybean Association, the North Central Soybean Research Program and the United Soybean Board.

ISU Research

Key advances from the last five years of research on SDS at Iowa State include :

• Development and release of soybean breeding lines with improved resistance to SDS that can be used by seed companies to develop resistant varieties adapted to Iowa;
• Discovery, identification and molecular characterization of a toxin produced by the SDS fungus that causes the disease and that the toxin needs to be exposed to light to cause the disease on the leaves;
• Discovery that the fungus needs to colonize the central part (or vascular system) of the roots so the toxin can be moved up from the roots to the leaves in the cells that carry water up the plant;
• Discovery that soybean seedlings are most vulnerable to root infection in the first few days after planting, and in cold soils the seedlings are vulnerable to infection for a longer period of time than when planting occurs in warmer soil;
• Discovery that the SDS fungus can survive in corn residue, including corn kernels dropped in field, and this may be a way the fungus overwinters from season to season.

Several other ongoing projects include :

• Sequencing of the entire genetic composition (genome) of the SDS pathogen, which will allow scientists to identify the genes involved in the ability of the fungus to cause disease on soybeans;
• Identifying the mechanisms behind the interaction between the SCN and the SDS pathogen;
• Identifying soybean genes involved in resistance to SDS using molecular approaches;
• Continuing to screen soybean breeding populations adapted to Iowa for improved resistance to SDS;
• Evaluating the impact of crop rotation, planting date and seed treatment for SDS management in Iowa.

Partially funded by the soybean checkoff.

Iowa Master Gardeners (MG) find many ways to volunteer in their communities, from answering horticulture questions that come into county offices to helping manage farmers' markets and community gardens. Public plantings in many Iowa communities are visual signs of the many volunteer hours Master Gardeners provide.

Master Gardener training has been offered in Iowa by Iowa State University Extension since 1979. Over the years, more than 10,000 Iowans have received instruction on a wide range of horticulture and related topics and in return provided a specified number of hours doing volunteer outreach through ISU Extension.

However, there are Iowans that would like to have the training, without the commitment of providing community service. To better serve this group of people, ISU Extension Scott County is offering the ProHort Certification for the first time this year. The ProHort Certification program will be delivered through the Iowa State University Master Gardener training program this fall in three locations. It is different from the Master Gardener program because it is a fee in-lieu-of volunteer service version of the program.

"ProHort participants will train alongside Iowa Master Gardeners," said Jennifer Bousselot, Iowa MG coordinator. "However, without the volunteer commitment, participants do not become Iowa Master Gardeners."

The Iowa Master Gardener (MG) training includes sessions on animal ecology, botany, entomology, fruit culture, herbaceous ornamentals, home landscape design, houseplants, integrated pest management/pesticides, landscape plants, plant pathology, soils, turf grass management, vegetables and weed management.

Upon completion of the program requirements, ProHort participants receive an official ProHort Certificate of training from Iowa State University, which may be displayed in a place of business.

To find out more about the ProHort Certification program being offered in Scott County this fall, contact Duane Gissel, ISU Scott County Extension 563-359-7577.

August 5                               
Pesticide Applicator Testing
10am-2pm at the Extension Office

August 23                             
Scott County Extension Council Meeting at the Extension Office
7pm 

September 2                       
Pesticide Applicator Testing
10am-2pm at the Extension Office 

September 27                     
Scott County Extension Council Meeting at the Extension Office
7pm 

October 5                             
Aquatic, Forest and Roadside Pest Management CIC, $35 if registered by 9/28/11, after that $45
At the Scott County Extension Office, 9am-11:30am 

October 7                             
Pesticide Applicator Testing
10am-2pm at the Extension Office 

October 25                           
Scott County Extension Council Meeting at the Extension Office
7pm 

October 27                           
Mosquito & Public Health Pest Management CIC, $35 if registered by 10/20/11, after that $45
At the Scott County Extension Office, 9am-11:30am 

November 4                        
Pesticide Applicator Testing
10am-2pm at the Extension Office 

November 9                        
Ornamental & Turf Applicators CIC, $35 if registered by 11/2/11, after that $45
At the Scott County Extension Office, 1:30pm-4pm 

November 16                      
Commercial Ag Weed, Insect, and Plant Disease Management CIC, $35 if registered by 11/9/11, after that
$45, at the Scott County Extension Office, 9am-11:30am 

November 29                      
Fumigation CIC, $35 if registered by 11/22/11, after that $45, at the Scott County Extension Office,
9am-11:30am 

December 2                        
Pesticide Applicator Testing
10am-2pm at the Extension Office 

December 7                        
Pest Control Operators CIC, $35 if registered by 11/30/11, after that $45, at the Scott County Extension
Office, 9am-11:30am