Characterization of the relationship between whiteheads and yield loss at different seeding rates in rice (Oryza sativa L.)

The Mexican rice borer (MRB, Eoreuma loftini) is the primary borer pest affecting rice (Oryza sativa L.) production in Texas causing yield losses of up to 50%. MRB larvae bore stems resulting in dried panicles leading to "whitehead" symptom. Current management for MRB relies exclusively on insecticidal seed treatment Chlorantraniliprole, raising concerns about development of insecticide resistance if alternatives are not available. This study will investigate the relationship of seeding rate on MRB incidence (whiteheads) and yield loss based on different panicle densities (seeding rates) in a conventional rice variety ‘Cheniere’. We hypothesize that higher seeding rates would lead to fewer whiteheads as increased plant density may restrict MRB access for oviposition, suggesting that higher seeding rates might decrease overall yield loss. A field experiment will be conducted in a randomized complete block design with four replications at the Texas A&M AgriLife Research Center, Beaumont, Texas. A 5x2 factorial design, using five seeding rates (35, 70, 105, 140, 175 lbs/acre), and two levels of insecticide (presence or absence of Chlorantraniliprole, an anthranilic diamide seed treatment). Field plots will be exposed to natural MRB infestations and numbers of whiteheads will be recorded weekly until panicle maturity. Yield loss percentages and seeding rate combinations will be compared using ANOVA. Results will be discussed later. By understanding the interaction of MRB incidence and yield loss at different panicle densities, this study will benefit rice producers because it will help to the development of cultural practices (optimal seeding rates) for minimizing yield loss.