TRIPSACUM DACTYLOIDES (GRAMINEAE) SEEDLINGS FOR HOST-PLANT RESISTANCE TO THE WESTERN CORN-ROOTWORM (COLEOPTERA, CHRYSOMELIDAE)

Mature plants and cuttings of Tripsacum dactyloides (L.) have shown resistance to western corn rootworm, Diabrotica virgifera virgifera LeConte, larvae. The purpose of our study was to evaluate seedling-stage ?: dactyloides for resistance to western corn rootworm larvae. Two evaluations were conducted using 50- to 56-d-old T. dactyloides seedlings and maize, Zea malls L., checks. In the Ist evaluation, rootworm larvae, 4, 5, and 6 wk after infestation, weighed significantly less than feeding on T. dactyloides when compared with larvae feeding on the maize checks. In the 2nd evaluation, only 3 larvae were found on a total of 20 T. dactyloides seedlings, whereas the susceptible maize controls averaged >1 larva per plant. These results indicate the presence of corn rootworm resistance in T. dactyloides seedlings that may be transferable into commercial maize.