Predicting Mexican rice borer (Lepidoptera: Crambidae) populations in non-crop hosts of Gulf Coast agroecosystems

After expanding its range from Mexico into Texas, the Mexican rice borer, Eoreuma loftini (Dyar), was detected in Louisiana in 2008. E. loftini is a severe pest of sugarcane and rice, and also infests a wide range of grasses. The role of E. loftini infestations in non-crop grasses has only recently received consideration for pest management. A spatially explicit model is being developed to assist in determining whether the manipulation of non-crop hosts will help manage E. loftini and be cost effective. Building on results from multi-area transect sampling, greenhouse experiments, and literature on E. loftini or closely related species, theoretical analyses forecasting population dynamics under various management scenarios are performed. Management tactics include mowing, herbicides, and insecticides applied at field or regional levels. A distributed-maturation algorithm is used to predict aging of E. loftini cohorts based on a degree-day time scale. In addition to seasonality and movement, development, survival, fecundity, and oviposition estimates for E. loftini cohorts as affected by plant hosts are included in simulations. Results from this whole systems approach will help design optimal tactics reducing E. loftini populations in sugarcane and rice agroecosystems of the Gulf Coast region.