THE MAIZE BILLBUG AND DIATRAEA SPP.: INSECTS AFFECTING THE SEED PRODUCTION OF EASTERN GAMAGRASS

Authors: Springer, Timothy; Maas, David; Gillen, Robert; Sims, Phillip

Submitted to: International Herbage Seed Conference
Publication Type: Proceedings
Publication Acceptance Date: 7/13/2003
Publication Date: 11/23/2003
Citation: SPRINGER, T.L., MAAS, D.L., GILLEN, R.L., SIMS, P.L. 2003. THE MAIZE BILLBUG AND DIATRAEA SPP.: INSECTS AFFECTING THE SEED PRODUCTION OF EASTERN GAMAGRASS. INTERNATIONAL HERBAGE SEED CONFERENCE. p. 187-191.

Interpretive Summary: The utilization of eastern gamagrass for pasture, hay, and soil stabilization is increasing every year and other uses such as grain for human consumption or pharmaceuticals from this amazing plant are being explored. As the number of acres of eastern gamagrass increases in the USA the incidence of disease and insect pests has become more evident. Diseases and insects common in maize are causing serious problems in gamagrass. At Woodward, OK, the maize billbug, southern cornstalk borer, and southwestern corn borer reduce seed production of gamagrass. Adult billbugs feed on shoots leaving a transverse row of holes across the leaf blade. This feeding pattern also occurs in maize. Female billbugs chew small holes into the base of culms where they deposit eggs. The culm slowly dies as larvae feed. Larvae of the southern cornstalk borer and southwestern corn borer cause damage by feeding on leaves and boring into the culms. Adults of these insects lay their eggs in the upper plant canopy. Once eggs hatch, the larvae feed in the local area where eggs were laid creating a 'windowpane' effect on the leaf. Larvae move down the culm feeding on lateral inflorescences and eventually bore into the culm where they complete their life cycle. We anticipate that the control of these insects will be solved through an integrated approach of plant breeding and cultural practices.

Technical Abstract: The maize billbug, Sphenophorus maidis (Chittenden), southern cornstalk borer, Diatraea crambidoides (Grote), and southwestern corn borer, Diatraea grandiosella Dyar, reduce seed production of eastern gamagrass, Tripsacum dactyloides (L.) L., at Woodward, Oklahoma, USA. Adult maize billbugs feed on shoots leaving a transverse row of holes across the leaf blade. This feeding pattern commonly occurs in maize, Zea mays L., as well. Female billbugs chew small holes into the base of culms where they deposit eggs. The culm slowly dies as larvae begin to feed and complete their life cycle. Larvae of the southern cornstalk borer and southwestern corn borer cause damage by feeding on leaves and boring into the culms. Adults of these insects lay their eggs in the upper canopy of the plant. Once eggs hatch, the larvae feed in the local area where eggs were laid creating a 'windowpane' effect on the leaf. Larvae move down the culm feeding on lateral inflorescences and eventually bore into the culm where they develop and complete their life cycle. As with the billbug, culms slowly die as the larvae develop, thus reducing over all plant vigor and seed production.