Gd. Buntin et al., Evaluation of yieldgard transgenic resistance for control of fall armywormand corn earworm (Lepidoptera : Noctuidae) on corn, FLA ENTOMOL, 84(1), 2001, pp. 37-42
Fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helic
overpa tea Boddie, perennially cause leaf and ear damage to corn in the sou
theastern USA. Development of transgenic hybrids expressing insecticidal en
dotoxin from Bacillus thuringiensis (Bt) offers a new approach to managing
these insects in field corn. Transgenic Pt hybrids with either the Bt11 or
MON810 event, collectively known as YieldGard Technology, were evaluated fo
r control fall armyworm and corn earworm in southern Georgia during 1998, w
hich coincided with a severe outbreak of fall armyworm. YieldGard Pt resist
ance consistently reduced whorl infestation and damage to low levels and al
so reduced ear infestations and larval numbers per ear. However, larval est
ablishment did occur on many ears of resistant plants, but once established
in ears, larvae of both species developed more slowly and caused much less
kernel damage on resistant than susceptible plants. We found no relationsh
ip between YieldGard Bt resistance and corn grain aflatoxin concentrations.
Yield responses were variable with the prevention of yield loss being prop
ortional to the severity of insect damage. These results indicate that Yiel
dGard resistance is effective in preventing significant losses to field cor
n by fall armyworm and corn earworm. Further, evaluation under a variety of
growing conditions and insect infestation levels is needed to clearly asse
ss the value of YieldGard technology to corn growers in the Southeast.