Comparison of Nonmaize Hosts to Support Western Corn Rootworm (Coleoptera: Chrysomelidae) Larval Biology

With the recent commercialization of transgenic rootworm-resistant maize with high levels of antibiosis to larval feeding, the biology of western corn rootworm, Diabrotica virgifera virgiferaLeConte, on hosts beyondmaize,Zea maysL., has become an important topic for which data are limited.Larval survivorship andgrowthparametersweremonitoredon the roots of 29plant species comprised of maize, maize-Þeld weeds, native prairie grasses, forage grasses, and small grain crops. Data on larval recovery and growth (measured as increases in head capsule width and accumulation of dry weight) were recorded at Þve samplings (6, 10, 14, 20, and 24 d) after initial infestation of the 29 species. Recovery and growth parameters were analyzed for interand intraspeciÞc differences within and among sampling dates. Larvae survived at least 6 d after infestation on 27 species and 24 d on 23 plant species. Larval recovery and growth were impacted by both species and time after infestation.Growth anddevelopment of larvaewere signiÞcantly slower onmost plant species beyond maize; however, 18 of the species had larvae develop to the second instar, whereas larvae on 14 species developed to the third instar. Adults were recovered from Þve plant species in addition to maize. Because rootworm-resistant transgenic maize with high levels of antibiosis has become a part of the agroecosystem, weeds in grassymaize Þelds as well as adjacent forage grass speciesmay becomemore important in the western corn rootworm life cycle, particularly because genes conferring resistance to postemergent herbicides such as glyphosate are stacked with transgenic rootworm-resistant maize hybrids.