Progress 10/01/04 to 09/30/07
Outputs
OUTPUTS: Surveyed for soybean cyst nematode (SCN) in South Dakota Counties Measured persistence of SCN in soybean fields in roberts and Turner Counties Measured the effect of SCN infestations on yields of a wide range of commercial soybean varieties in Turner and Clay Counties. Evaluated reporduction of SCN on field peas in field and greenhouse studies PARTICIPANTS: Dr. Marty Draper, SDSU- Plant Science; Dr. Roy Scott, SDSU- Plant Science, Dr. Larry Osborne, SDSU-Plant Science Partner organizations: South Dakota Soybean Research and Promotion Council. Collaborated with SDCES to disseminate research and survey results TARGET AUDIENCES: NC-215 South Dakota soybean producers SDCEs county-based Extension Educators PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Assisted soybean growers in Clay, Deuel, Hutchinson, Lincoln, Union, Turner, Robers, Minnehaha, and Yankton Counties with development of management plans for soybean cyst nematode. Coordinated research and extension activities at Northeast Research Station. Collaborated with soybean breeder to evaluate breeding lines for sources of soybean cyst nematode resistance. Collaborated with CES Plant Pathology Specialist to disseminate research results through publication, field plot tours, and written materials (paper and electronic)
Publications
- Smolik, J.D. Editor. 2004-2006. Northeast Research Station Annual Progress Report. Plant Science Pamphlet No. 23. SDAES
- Smolik, J.D. 2006. Fifty-year yield summary. 2005 Northeast Research Station Annual Progress Report.
- Smolik, J.D. 2006. Nematode Studies in South Dakota. North Central Annual Report.
- Smolik, J.D. 2006. Soybean Cyst Nematode Studies Section 0518 http://plantsci.sdstate.edu/southeastfarm/
- Smolik, J.D. 2006. Effect of Crop Rotation and Tillage on Nematode Populations Section 0517. http//plantsci.sdstate.edu/southeastfarm/
- Osborne, L.E., J.D. Smolik, S.L. Osborne. 2004. Nematode Communicty Dynamics in No-till Crop Rotations for the Northern Great Plains. Agronomy Society Abstracts.
- Smolik, J.D. and M.A. Draper. 2003. Soybean cyst nematode. SDCES Extension No. 902-A Revised Feb 2003.
- Smolik, J.D. 2003. Nematode studies in South Dakota NC-215 Annual Report.
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Progress 01/01/06 to 12/31/06
Outputs
Approximately 1200 samples were processed for SCN in 2006, and nearly 50% were positive for SCN. This was the highest infestation rate recorded in our surveys over the past 12 years. The number of counties where SCN has been found remains at nineteen. A large number of samples were received from Lincoln County and 68% were positive for SCN. Thus, Lincoln County joins Union, Clay, and Turner as counties with very high levels of SCN-infested fields. A replicated, field-scale strip test was established in a cooperator's irrigated field to measure yields of SCN resistant vs susceptible soybean. Yields of the resistant varieties were 15 to 32% higher than the susceptible varieties and population densities of SCN were substantially lower on the resistant varieties at harvest. Soybean yields and SCN populations were also measured in a second replicated strip trial. Yields of the resistant varieties were 8 to 27% higher than the susceptible and population densities of SCN at
harvest were again lower on the resistant varieties. We continued to investigate the status of field pea as a host for SCN in a field trial. The trial measured reproduction of SCN on two varieties of field pea and on resistant and susceptible soybean. Population densities of SCN declined from initial levels on both field peas, increased slightly on the resistant soybean and increased nearly 6-fold on the susceptible soybean variety. Yield of the SCN-resistant variety was nearly 50% greater than the susceptible variety. Based on this and previous years field and greenhouse studies it appears that rotating to field peas in SCN-infested fields will not result in increased SCN population densities. In cooperation with the soybean breeder, population densities of SCN on experimental and commercial soybean lines were measured. Several of the experimental lines appeared to possess a useful level of SCN resistance. The reproduction of SCN on experimental soybean lines was also measured in a
greenhouse study. Several of the SD experimentals appeared resistant to SCN, and one of the lines also performed well in the field study. Nematode population densities were determined in the alternative cropping system studies established in 2003. These studies include stacked rotations, continuous cropping, and 2-year rotations. Numbers of stunt nematodes were low in all systems. The highest population densities of spiral nematodes occurred on corn. Numbers of pin nematode were highest on soybean, which was also observed the previous year. Dagger nematode numbers in excess of 100 per 100cc soil will significantly reduce yield, and it appears that corn and soybean yields were reduced by this nematode in several of the systems. Highest numbers of lesion nematodes occurred on continuous corn. In general, the lowest populations of plant feeding nematodes occurred on spring wheat. Cropping system had little consistent effect on numbers of dorylaims. The lowest population densities of
microbial feeding nematodes occurred in continuous soybean.
Impacts
The SCN is considered the most damaging pest of soybeans in the US, and losses have been estimated at 1 billion dollars annually. This nematode is well adapted to the intermittent availability of its host, and understanding the biology of SCN and other plant parasitic nematodes associated with soybean is critical to developing long-term management recommendations.
Publications
- Smolik, J.D. 2006. Soybean Cyst Nematode Studies, Section 0518 at: [http://plantsci.sdstate.edu/southeastfarm/]
- Smolik, J.D. 2006. Effect of Crop Rotation and Tillage on Nematode Populations, Section 0517 at [http://plantsci.sdstate.edu/southeastfarm/]
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Progress 01/01/05 to 12/31/05
Outputs
. The Soybean Cyst Nematode (SCN) has been detected in nineteen counties in South Dakota. Approximately 35% of samples received for nematode testing in 2005 were infested with SCN. A field-scale strip test was established in a cooperator's irrigated field to compare SCN resistant vs susceptible soybeans. Yields of the resistant varieties were 18-58% higher than the susceptible varieties. A second strip trial was established in a heavily infested, non-irrigated field. Yields of the resistant varieties were 26-54% higher than the susceptible varieties. All of the resistant varieties suppressed reproduction of SCN in both tests. A greenhouse experiment was conducted to measure reproduction of SCN on field pea. None of the twenty-two pea varieties were a host for SCN. The reproduction of SCN on pea was also measured in two field studies, and SCN did not increase on pea at either location. The reproduction of indigenous nematodes from several western SD prairie locations
was measured on soybean in greenhouse studies. To date, only spiral nematodes appear to readily reproduce on soybean. Soil samples were collected in the fall from a long-term cropping systems study in southeastern SD for the fifth consecutive year. The systems included a no-till corn-soybean rotation (NT2), Aerway-till corn-soy (AT2), conventional till corn-soy (CT2), no-till corn-soy-spring wheat (NT3), conventional till corn-soy-spring wheat CT3), NT3 plus alfalfa (NT4), and CT3 plus alfalfa (CT4). Populations of stunt nematodes were again low in all rotations. Crop rotations had little consistent effect on spiral nematodes. Pin nematode numbers were highest in soybean in the 4-yr rotations. Dagger nematode populations were highest on alfalfa in the CT rotation, and it is likely they reduced alfalfa yields. Crop rotation had no consistent effect on populations of dorylaims or microbial feeders. The highest populations of spirial and pin nematodes occurred in the NT rotations, and
highest numbers of Tylenchinae occurred in the CT rotations. Populations of both dorylaims and microbial feeders were higher in the CT rotations. The average nematode population in the rotations over the past 5 years was also compared. Spiral nematode populations were highest in the 2-yr AT rotation and pin nematodes were highest in the 4-yr CT rotation. Populations of Tylenchinae were highest in CT rotations. The 4-yr rotations that include alfalfa had the highest dagger nematode populations. Lesion nematode numbers were highest in the 2-yr rotations. Populations of both dorylaims and microbial feeders were highest in the CT rotations. Nematode population measurements were also initiated in the alternative cropping system studies established in 2003. These studies include stacked rotations, continuous cropping, and 2-year rotations. In general, nematode population densities were highest following soybean. The highest populations of dagger nematodes occurred in the continuously
cropped soybeans and were at a level that very likely would reduce yield. The lowest populations of nematodes generally occurred following spring wheat
Impacts
The SCN is considered the most damaging pest of soybeans in the US, and losses have been estimated at 1 billion dollars annually. This nematode is well adapted to the intermittent availability of its host, and understanding the biology of SCN and other plant parasitic nematodes associated with soybean is critical to developing long-term management recommendations.
Publications
- Smolik, J.D. 2005. Soybean Cyst Nematode Studies, in 2004 SESD Exp. Farm 44th Annual Progress Report. pp 96-100.
- Smolik, J.D. 2005. Effect of Crop Rotation and Tillage on Nematode Populations, in 2004 SESD Exp Farm Annual Progress Report. pp. 94-95.
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