Evaluation of maize germplasm from Saint Croix for resistance to leaf feeding by fall armyworm.
Maize (Zea mays L.) is a preferred host of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera:Noctuidae), with larvae primarily feeding on developing leaves and ear tissue. The fall armyworm is resistant to several classes of insecticide and Bt-maize grown in certain areas. Native sources of plant resistance to the pest are available for public use, but new sources of resistance need to be discovered and developed. The objective for this study was to test maize germplasm collected from Saint Croix, U.S. Virgin Islands, for resistance to leaf feeding by fall armyworm. Plants were grown in the field and artificially infested at a high level. Scores of damage by fall armyworm feeding on leaves at 7 and 14 days differed significantly for the 13 maize genotypes tested. Scores at 14 days for Saint Croix Group 1 (5.8), Saint Croix Group 3 (5.6), Saint Croix 2 (5.6), and Saint Croix 7 (6.0) were moderately resistant and not significantly different from one another. Individual plants in the populations were variable for resistance to leaf feeding, and scored between 4 and 7. It should be possible to select within the populations for greater resistance to damage by fall armyworms feeding on leaves.