The Georgia Agricultural Experiment Stations College of Agricultural and Environmental Sciences The University of Georgia Research Report Number 713 December 2007 Sorghum Midge Resistance in 15 Grain Sorghum Hybrids­2007 Xinzhi Ni, G. David Buntin, and J. Charles Mullis 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), leaf­footed bug, chinch bug, and sorghum webworm. The midge­infested heads can be separated from seed losses by other factors using the whitish­cast skins hanging at the tip of glumes during pre­harvest 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 2007 growing 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 ‘FFS­0627’) which 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 = 10­25% of empty glumes on a sorghum head observed (10­25%); 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 disease­resistant 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, USDA­ARS, Coastal Plain Experiment Station, Tifton, Georgia.
Evaluations of Grain Sorghum Hybrids for
Resistance to the Sorghum Midge, 2007,
Tifton, Georgia1
Brand
Hybrid
Days to
Anthesis2
Asgrow
Asgrow
DeKalb
Moss
Moss
A-603
A571
DKS54-00
M929MB
M1024DPW
58
63
64
60
64
VG
VG
VG
VG
VG
DeKalb
Plantation Seeds
Pioneer
FL
FL
DKS53-67
GS106
82G10
FFS-0627
FL(A31/BK6-1)
64
74
65
90
66
VG
VG
VG
VG
VG
Plantation Seeds
Pioneer
FL
FL
Moss
GS406
83G66
FGS-0612
FGS-0620
M927ER
66
61
80
75
55
G
G
G
G
F
Midge
Resistance3
1. The test plots were irrigated four times (each with an inch of water), and fertilized
using 25 lb N, 50 lb P, and 75 lb K/acre, as well as sidedress of 100 lb N/acre.
2. Days from planting to 50% bloom.
3. For sorghum midge resistance, VG = very good, G = good, F = fair, and P = poor.