ANATOMICAL CHARACTERISTICS OF MAIZE RESISTANT TO LEAF FEEDING BY SOUTHWESTERN CORN-BORER (LEPIDOPTERA, PYRALIDAE) AND FALL ARMYWORM (LEPIDOPTERA, NOCTUIDAE)

Maize, Zea mays L., inbred lines with resistance to leaf feeding by th e larvae of the southwestern corn borer. Diatraea grandiosella Dyar, a nd the fall armyworm, Spodoptera frugiperda (J. E. Smith) have been re leased. The mechanisms of resistance are larval antibiosis and nonpref erence; however, the factor or factors causing the resistance are not fully understood. In this study, selected anatomical characters of inn er whorl tissue of several leaf feeding susceptible and resistant maiz e inbreds were compared. For both insect species, correlations were ca lculated between the anatomical characters and leaf feeding damage sco res and between the anatomical characters and weights of larvae. Signi ficant differences were detected between several anatomical characters of the resistant and susceptible inbreds. The most striking and consi stent difference between the resistant and susceptible inbreds was the thickness of the cuticle and the epidermal cell wall (cell wall compl ex). The cell wall complex of the resistant inbreds was 1.7x thicker t han that of the susceptible inbreds. Significant correlations existed between anatomical characters of the inner whorl and both leaf feeding damage scores and larval weights. The characters most closely associa ted with leaf feeding damage and larval weights were the upper and low er cell wall complexes. The inner whorl tissue from the resistant inbr eds tended to be tougher than comparable tissue of the susceptible inb reds.