A to D, Effects of Pr4- or Endochitinase A-treated maize leaves on the growth of C. heterostrophus. Maize leaves were wounded and treated with recombinant Pr4, Endochitinase A, or buffer or left undamaged (control) for 24 h and treated with equal amounts of C. heterostrophus spore inoculum on the upper half of the midrib or with water on the lower half of the midrib (A and C). Fungal growth was measured as a percentage of the leaf area infected after 60 h by determining the area of infected lesions (B and D). Six plants were used as biological replicates for each treatment. Percentage leaf area values with different letters are significantly different from each other according to one-way ANOVA and mean separation by Tukey’s test (P < 0.05). Error bars indicate se. E and F, Effects of recombinant Pr4- or Endochitinase A-treated maize leaves on the growth rate of naïve FAW caterpillars. Maize leaves were wounded and treated with recombinant Pr4 or Endochitinase A protein or buffer or left undamaged (control) for 24 h. Leaf tissue from 18 plants from each treatment was fed to naïve FAW caterpillars, and their relative growth rate (RGR) was measured after 3 d. RGR values with different letters are significantly different from each other according to one-way ANOVA and Tukey’s mean separation (P < 0.05). Error bars indicate se.