|Buntin, G. David - UNIV OF GA|
Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: December 17, 2007
Publication Date: January 22, 2008
Citation: Ni, X., Buntin, G., Mullis, J.C. 2008. Sorghum midge resistance in 15 grain sorghum hybrids - 2007. Georgia 2007 Soybean, Sorghum Grain and Silage, and Summer Annual Forages Performance Tests, Research Report 713, Georgia Agricultural Experiment Station. Interpretive Summary: not required
Technical Abstract: Grain sorghum is a good rotation crop in the Georgia Coastal Plain region. However, the grain sorghum crop is 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 recorded in 2007. They were, in order of importance: sorghum midge, fall armyworm, corn earworm, aphids (corn leaf aphid and greenbug), stink bugs (southern green and brown stink bugs), leaf-footed bug, chinch bug, and sorghum webworm. 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. The overall damage caused by the sorghum midge was very low in comparison with data from the previous years, which is probably caused by the extreme drought conditions during the 2007growing season. Fifteen hybrids were evaluated for resistance to sorghum midge in 2007. The hybrids were planted with 4 replications on April 26, 2007. The flowering (anthesis) date was recorded during June and July because of one entry (Hybrid ‘FFS-0627’) had an extremely late flowering time. Sorghum midge damage was rated on August 20, 2006. The midge damage given in the following table is expressed according to the visual rating of grain loss based on four replications. Sorghum midge damage was rated in the plots according to the following rating scale; Very Good = no empty glumes on any of the sorghum heads in an experimental plot; Good = a few empty glumes (< 10%) observed on a head; Fair = 10-25% of empty glumes on a sorghum head observed (10-25%); and Poor = majority of sorghum heads with more than a quarter (25%) of empty glumes. Sorghum midge resistance was observed in all 15 cultivars, except one. Please refer to the following table for further details on flowering time and midge damage ratings. Because other insect pest damage and grain mold were minimal, only sorghum midge damage was being evaluated in 2007. It is highly recommended that growers use available insect and disease-resistant hybrids, which is one of the most economic pest strategies for sorghum production in our region. For further integrated insect management information, please consult with your local county agent and/or extension entomologists. This test was maintained and data were collected by J. C. Mullis, and Wesley Pope of the Crop Genetics and Breeding Research Unit, USDA-ARS, Coastal Plain Experiment Station, Tifton, Georgia.