|Buntin, G. David -|
Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: November 15, 2011
Publication Date: December 1, 2011
Citation: Ni, X., Buntin, G. 2011. Grain sorghum hybrid resistance to insect and bird damage - 2011. In: Day, J.L., Coy, A.E., Gassett, J.D., editors. Georgia 2011 Soybean, Sorghum Grain and Silage, and Summer Annual Forages Performance Tests, Georgia Agricultural Experiment Stations Annual Publication 103-3, Athens, GA. Interpretive Summary: not required
Technical Abstract: Nine grain sorghum hybrids were evaluated for resistance to sorghum midge and bird damage in 2011. Although their damage was relatively low in general in 2011, nine 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, corn leaf aphid, chinch bug, sorghum head worm complex (mainly sorghum webworm and corn earworm), and stink bugs (southern green and brown stink bugs). Diseases were of minimal importance in our experimental plots in 2011. The hybrids were planted with 4 replications on April 26, 2011. The flowering date (or days to anthesis) was recorded in June. The flowering time (50% panicles are flowering) of the nine hybrids was between 51 and 63 days after planting. The fall armyworm and aphid damage was assessed in May and June. Because the foliar damage ratings were low in general, the data were not included in the table. Sorghum midge and bird damage was rated on July 27, 2011. Midge damage was rated according to the visual estimates of grain loss. Grain loss caused by midge infestation can be separated from other factors using the whitish-cast skins hanging at the tip of glumes during pre-harvest examination. Sorghum midge damage was assessed according to the following rating scale: Very Good = 0-15% of empty glumes on any of the sorghum panicles in an experimental plot; Good = a few empty glumes (16-30%) observed on a panicle; Fair = 31-75% of empty glumes on a sorghum panicle; and Poor = majority of sorghum panicles with more than three quarters (> 75%) of empty glumes. In addition, the assessment of bird damage on developing kernels was based on the following scale: Very Good (VG) = less than 10% grain 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. Midge damage was very low (rated as < 30% grain loss) in general for 2011 with the April planting, which could also be the result of relatively dry weather conditions. For midge resistance, most of the hybrids (6 of the 9 entries) showed no damage and were rated as Very Good (VG). The three hybrids showed the most midge damage in 2011 were 84P80, 772B, and AG3101, although the damage ratings were not greater than 30%. In addition, all entries showed bird damage when it was evaluated on July 27, which was three months after planting and about one month after flowering. All bird damage ratings were also relatively low (= 25%). The hybrids AG3201, 84P80, and 772B showed less bird damage than the other six hybrids. 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 from the Crop Genetics and Breeding Research Unit, USDA-ARS, Coastal Plain Experiment Station, UGA-Tifton, Georgia.