|TOEWS, MICHAEL - University Of Georgia|
|BUNTIN, G. DAVID - University Of Georgia|
Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: 11/28/2012
Publication Date: 12/14/2012
Citation: Ni, X., Toews, M.D., Buntin, G. 2013. Grain sorghum hybrid resistance to insect and bird damage in 2012. In: J. L. Day, A. E. Coy, and J. D. Gassett (eds.). Georgia 2012 Soybean, Sorghum Grain and Silage, and Summer Annual Forages Performance Tests, Georgia Agricultural Experiment Stations, Annual Publication, Athens, GA December 2012. 103-5. Available: http://www.swvt.uga.edu/2012/sysr12/AP103-4-SR-grain.pdf (Technical Report).
Interpretive Summary: not required
Technical Abstract: Seven grain sorghum hybrids were evaluated for resistance to insect and bird damage in 2012. Although their damage was relatively low in general in 2012, five insect pests were observed on sorghum in south Georgia. They could be listed in order of importance as follows: sorghum midge, leaf-footed bug, fall armyworm, and stink bugs (southern green and brown stink bugs). Aphid, headworm complex (i.e., corn earworm, and sorghum webworm), and chinch bug populations were low, so were plant diseases in the experimental plots in 2012. The hybrids were planted with 4 replications on June 13, 2012. The flowering date (or days to anthesis) was recorded in August. The flowering time (50% plants with flowering panicles) of the seven hybrids was 60-63 days after planting (as shown in Table 1), ranging between 58 and 65 days in the four replications. The whorl damage by natural fall armyworm population was assessed on July 16, 2012. Because there was no difference in fall armyworm damage among the hybrids, the data were not included in the table. Sorghum midge and bird damage was rated on September 25, 2012. The sorghum midge damage was rated according to the visual estimates of grain loss. Grain loss caused by the midge infestation can be separated from other factors using the whitish-cast skins hanging at the tip of glumes during pre-harvest examination. The sorghum midge damage was assessed according to the following rating scale: Very Good = 0-15%; Good = 16-30%; Fair = 31-75%; and Poor = more than three quarters (> 75%) empty glumes per sorghum panicle. In addition, the assessment of bird damage on developing kernels was based on the following scale: Very Good (VG) = less than 10% loss; Good (G) = 11-25% loss; Fair (F) = 26-50% loss; and Poor (P) = over 50% loss of grains per panicle. The bird damage could be reduced by timely harvest of the crop in general. The sorghum midge is a cyclic insect pest in grain sorghum production in the southern Coastal Plain region. The overall damage caused by sorghum midge is usually high on late flowering hybrids. The midge damage was very low in 2012, rated as Very Good (VG) (< 15% grain loss), in all hybrids except hybrid ‘83P17’ in 2012 with the June planting. Hybrid ‘83P17’ was rated good (G) (< 30% grain loss). In addition, all entries showed low level of bird damage when it was evaluated on September 25, 2012, which was more than three months after planting and over one month after flowering. All bird damage ratings were also relatively low (= 25%) this year in comparison with the previous years. The hybrids ‘AG3201,’ ‘83P17,’ and ‘XG3103’ showed less bird damage than the other four hybrids. Based on the data collected in 2012 with the principal components analysis, the two best hybrids showed resistance to fall armyworm, midge, and bird damage were ‘DKS53-67’ and ‘XG3103.’ It is highly recommended that growers use available insect- and disease-resistant hybrids, which is one of the most economical pest management strategies for sorghum production in our region. The information on both insect and bird damage might vary based on planting dates, with later plantings tending to have increased insect pest pressure. For further integrated insect management information, please consult with your local county agent and/or Extension entomologists. This test was maintained and flowering-date data were collected by Penny Tapp, Jonathan Roberts, and Joshua Gamblin from the Crop Genetics and Breeding Research Unit, USDA-ARS, Coastal Plain Experiment Station, UGA-Tifton, Georgia.