Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2012
Publication Date: 2/5/2013
Citation: Beuzelin, J.M., Meszaros, A., Wilson, B.E., Reagan, T.E., Wilson, L.T., Way, M.O., Showler, A. 2013. Oviposition and larval development of a stem borer, Eoreuma loftini, on rice and non-crop grass hosts. Entomologia Experimentalis et Applicata. 146(3):332-346. Interpretive Summary: We studied egg laying preference and larval development time of the Mexican rice borer, on rice and four weed hosts near rice fields, and analysis of the host plants for selected insect nutrients was conducted. Rice was more preferred for oviposition than the weeds, and young plants were less preferred than intermediate age and older plants. Mexican rice borer larval development was also fastest on rice, but development time was not affected by plant stage, excluding rice, where development was slower on younger than on older plants. Population dynamics on primary hosts of Texas Gulf Coast rice agroecosystems, and roles of biochemical insect nutrients relative to egg laying preference and performance are discussed.
Technical Abstract: A greenhouse study compared oviposition preference and larval development duration of a stem borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), on rice, Oryza sativa L. (cv. Cocodrie), and four primary non-crop hosts of Gulf Coast Texas rice agroecosystems. Rice and two perennials, johnsongrass [Sorghum halepense (L.) Pers.] and Vasey’s grass (Paspalum urvillei Steud.), were assessed at three stages. Two spring annuals, brome (Bromus spp.) and ryegrass (Lolium spp.), were assessed at two stages. During oviposition assessment, plant fresh biomass, dry biomass, and sum of tiller heights were recorded as measures of plant availability. Accounting for plant availability, rice was more preferred for oviposition than non-crop hosts, and young plants were associated with lower preferences than intermediate and older plants. The most preferred stages of johnsongrass and Vasey’s grass were associated with preference coefficients 40 to 68% smaller than those for the most preferred stages of rice. Brome received the lowest proportion of eggs and oviposition did not occur on ryegrass. Eoreuma loftini larval development duration in degree-days above a threshold temperature was fastest on rice and slowest on johnsongrass and Vasey’s grass. Development duration was not affected by plant stage, except on rice where larvae developed slower on younger plants. Oviposition preference coefficients and larval development durations can readily be integrated into population models to further the understanding of E. loftini dynamics on primary hosts of Texas Gulf Coast rice agroecosystems. On-going work on foliar and stem free amino acid concentrations may help provide insights on the bases of E. loftini preference and performance.