Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 8, 1996
Publication Date: N/A
Interpretive Summary: The fall armyworm is a perennial economic pest of field crops in the southern United States. Whorl-stage corn is particularly vulnerable to damage by the larvae of the fall armyworm. Resistance in corn to the fall armyworm would provide a method that is biologically, ecologically, economically and socially feasible for controlling the pest. The biological effects of the resistant GT-FAW-CC(C5) corn population on the larvae of the fall armyworm were studied at Mississippi State and Tifton. Fewer fall armyworm larvae fed on leaves of GT-FAWCC (C5) and their weight was less than those that fed on susceptible plants. This information adds to knowledge of the biological basis for corn resistance to fall armyworm larvae.
Field tests at Mississippi State, MS and Tifton, GA were conducted to demonstrate the effect of resistance of a maize, Zea mays (L.), germplasm population, 'GT-FAWCC(C5)' to feeding by larvae of the fall armyworm, Spodoptera frugiperda (J. E. Smith). Plants entries were infested at the 8 and 12 leaf stage with two applications of 15 larvae per plant. Resistance traits measured were: leaf damage at 7 and 14 days after infestation (DAI), number and weight of surviving larvae per plant at 7 and 10 DAI. Leaf damage ratings at both 7 and 14 DAI, number and weight of surviving larvae per plant on GT-FAWCC(5) at 7 and 10 DAI after infestation equalled the number and weight of surviving larvae on 'MpSWCB-4', the resistant check. Both the resistant check and GT-FAWCC(C5) were significantly more resistant to whorl damage than the susceptible check, 'Ab24E X SC229' for all resistance traits. It is evident that antibiosis (low weight) and nonpreference (fewer larvae/plant and fewer larvae preferring leaf samples) mechanisms of resistance are present in the GT-FAWCC(C5) population as well as for MpSWCB-4.