Influence of Western Corn Rootworm (Coleoptera: Chrysomelidae) Larval Injury on Photosynthetic Rate and Vegetative Growth of Different Types of Maize

Two field experiments were conducted in 1995–1996 to determine if there are common photosynthetic and vegetative growth responses among genotypes of maize, Zea mays L., to larval western corn rootworm, Diabrotica virgifera virgifera LeConte injury. Specific variables measured from rootworm infested and noninfested plants were midday leaf photosynthetic rate, plant growth stage, and plant height during 9–18 leaf growth stages. Three yellow-dent hybrids, five white food-grade dent hybrids, and a popcorn hybrid were included in the study. Results suggest that there may be a common negative photosynthetic response within maize to larval injury during vegetative growth stages. Transient reductions in photosynthetic rate occurred in rootworm infested maize at both low to moderate levels of root injury, which after a lag period, led to significant reductions in plant height. This trend was consistent across hybrids in both experiments during each year. Plant growth stage was not significantly affected by rootworm injury during vegetative periods.