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

Two Þeld experiments were conducted in 1995Ð1996 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. SpeciÞc variables measured from rootworm infested and noninfested plants were midday leaf photosynthetic rate, plant growth stage, and plant height during 9Ð18 leaf growth stages. Three yellow-dent hybrids, Þve 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 signiÞcant reductions in plant height. This trend was consistent across hybrids in both experiments during each year. Plant growth stagewas not signiÞcantly affected by rootworm injury during vegetative periods.