Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: November 30, 2005
Publication Date: December 15, 2005
Citation: Ni, X., Mullis, J.C. 2005. Evaluation of grain sorghum hybrids for resistance to the sorghum midge and sorghum ergot. In: J. L. Day, A. E. Coy, and P. A. Rose (eds.), Georgia 2005 Soybean, Sorghum Grain and Silage, and Summer Annual Forages Performance Tests, Research Report 702, pp. 43-44. Interpretive Summary: not required
Technical Abstract: Although grain sorghum is a good rotation crop, the plants are impacted by a variety of insects and pathogens from the seedling stage through maturity in the Coastal Plain region. Nine insect pests of sorghum in southern Georgia were detected in 2005. They are, in order of importance: the sorghum midge, the southern green and brown stink bugs, the sorghum webworm, the fall armyworm, the lesser cornstalk borer, the corn earworm, the greenbug, and the leaf-footed bug. In addition, during the growing season of 2005, sorghum ergot infection was also severe in the experimental plots. The midge-infested heads can be separated from seed losses by other factors using the whitish-cast skins hanging at the tip of glumes during pre-harvest examination. The sorghum midge is a cyclic pest in grain sorghum production in Tifton and the Coastal Plain region. Sorghum midge resistance was recorded in 8 of the 21 cultivars in the test, which was planted on May 10, 2005. Evaluation of grain sorghum for resistance to the sorghum midge was conducted on August 20, 2005. The midge damage given in the following table is expressed according to the visual rating of grain loss based on four replications. Although the other sorghum insect pests were observed on sorghum plants, the damage was not evaluated in 2005. It is highly recommended that growers use available resistant hybrids, one of the most economical strategies available for midge control. For further integrated insect management information, please consult with your local county agent and/or extension entomologists. Grain yield and quality loss caused by the sorghum ergot and other secondary fungal infections was severe, which was possibly associated with the relatively high precipitation and moderate temperatures around the flowering time of the plants. Five hybrids showed less infection of sorghum ergot than the rest of the entries. Please consult with extension plant pathologists for sorghum ergot and other plant disease management strategies. We thank Dr. Jeff Wilson, Crop Genetics and Breeding Research Unit, USDA-ARS, for sharing his expertise in diagnosing the sorghum ergot. This test was maintained and data were compiled by J. C. Mullis and P. Tapp of the Crop Genetics and Breeding Research Unit, USDA-ARS, Georgia Coastal Plain Experiment Station, Tifton, Georgia.