Monitoring to establish a model of southwestern corn borer (Lepidoptera: Crambidae) dynamics for the Texas High Plains

The southwestern corn borer, Diatraea grandiosella Dyar, and European corn borer, Ostrinia nubilalis Hüber, are major borer pests of maize, Zea mays, in the U.S. Although chemical and cultural controls currently are used in the Texas High Plains, stubble provides a spring innoculum of southwestern corn borer. Larvae damage the whorl and tassel of maize. Young larvae damage leaves within the whorl of vegetative-stage plants. Later in the season, larval tunneling in the stalk before pupation, resulting in extensive stalk lodging and reduction of harvest efficiency.

Dispersal must be understood to explain the biology and ecology of insect pests and develop effective pest management strategies. Understanding factors that influence distribution and abundance of insects is fundamental in integrated pest management because organisms exist with many species in an ecosystem.

Southwestern corn borer adults from three irrigated maize fields and two non maize fields on the Texas High Plains will be sampled with pheromone-baited traps during May to November 2008 and 2009. Abundance and distribution of eggs, small, medium, and large larvae and pupae during the two corn borer generations will be determined near each trap. Field data will be used to model the distribution and dispersal of southwestern corn borer moths in relation to crop development. The model will enable us prediction of emergence, estimate risk of establishment during the season, and indicate weather-related factors affecting southwestern corn borer.

Seasonal occurrence of feral adults also will be modeled under different environmental conditions to determine the life cycle of the pest with its host plant and weather.