Progress 09/01/24 to 08/31/25

Outputs
Target Audience:Rice producers/growers, extension agents, scientists Scientific conference of the Entomological Society of America: Entomology Annual Meeting 2025 Rice field days at Texas A&M AgriLife Research, Beaumont, Texas in July 2025and LSU Agricultural Research, Crowley, LA in June 2025 Texas A&M AgriLife Research Rice Field Day Student Competition July 2025 Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? A graduate student received hands-on training in greenhouse insect-rearing, oviposition bioassays, and plant-insect interaction experiments. Gained extensive experience conducting fieldrice trials, including insecticide timing studies, seeding-rate experiments, phenology monitoring, and collection of yield and injury data. Developed technical skills in experimental design, data collection, statistical analysis, and management of multi-stage insect development assays. Presented research findings at several scientific conferences, enhancing communication skills and professional visibility. Participated in Rice Field Days in Louisiana and Texas, engaging with growers, extension personnel, and industry partners. Strengthened professional development through mentoring, manuscript preparation, and exposure to applied research and extension activities. How have the results been disseminated to communities of interest? Findings were presented at regional and national scientific conferences, reaching entomologists, agronomists, and pest management researchers. Research updates were delivered at Rice Field Days in Louisiana and Texas, providing growers and industry representatives with applied recommendations. Preliminary data were incorporated into extension presentations and outreach materials, highlighting optimal insecticide timing and seeding-rate effects. What do you plan to do during the next reporting period to accomplish the goals? Complete development and validation of a phenologymodel for predicting optimal insecticide timing against MRB and SCB. Conduct additional greenhouse and field trials to refine understanding of varietal resistance and confirm stage-specific susceptibility patterns. Continue with multi-location field studies to test consistency of insecticide timing recommendations under different environmental conditions. Continue supporting the graduate student's training through data analysis, manuscript preparation, and conference presentations. Develop and disseminate extension materials summarizing best practices for stemborer management based on project findings.

Impacts
What was accomplished under these goals? Major Goals Identify rice growth stages most susceptible to Mexican rice borer (MRB) and sugarcane borer (SCB). Determine optimal timing of insecticide applications based on rice phenology. Evaluate how seeding rate and plant density influence stem borer injury and yield loss. Objective 1: Characterize MRB and SCB biologyand varietal resistance Outputs: two greenhouse experiments evaluated oviposition, larval boring, whitehead formation, and adult emergence in three rice varieties(Cheniere, CLL18, Jupiter, PVL03) across 4 growthstages. Oviposition preference (LSU): Both MRB and SCB laid significantly more eggs on reproductive stages (panicle differentiation through booting) than on vegetative stages. Cheniere received fewer eggs than PVL03, indicating that oviposition behavior contributes to resistance.Egg-laying was lowest during vegetative stages and peaked at the 5-cm panicle and late-booting stages. Larval boring (A&M): Boring success remained high overall (83-100%). Jupiter consistently showed reduced boring success and delayed boring, indicating partial resistance; PVL03 and CLL18 were uniformly susceptible. Damage formation (A&M): Booting and heading showed the highest deadheart/whitehead formation, confirming these as high-risk stages. Jupiter exhibited the lowest damage at several stages. Adult emergence (A&M): Emergence varied by stage and variety but was lowest at heading. No significant differences in development time, though CLL18 tended to develop more slowly. Overall: Reproductive stages were confirmed as the primary vulnerability window for both borer species, and varietal differences were documented for future breeding programs. Objective 2:Optimize insecticide timing using rice phenology Outputs: Onefield trial (LSU) with PVL03 tested lambda-cyhalothrin applications at five phenological stages. Weather station data collected for a degree-day model. Insecticide applications at 3-5 mm panicle and 1-5 cm panicle stages produced the lowest whitehead counts, aligning with greenhouse oviposition patterns (from Objective 1). Early vegetative applications were less effective. Environmental data are being incorporated into a degree-day model to predict optimal spray timing. Objective 3:Assess seeding rate, stand density, and insecticide interactions Outputs: two (A&M) field experiments: (1) high vs. low seeding rate × insecticide, and (2) five seeding rates × insecticide. One (LSU) field experiment: high vs low seeding rate. Collected yield, whitehead counts, and grain-weight data. Plant density effects: Whitehead density decreased as seeding rate increased, indicating a dilution effect. Yield was strongly driven by seeding rate rather than insecticide. Insecticide performance: Dermacor reduced whitehead counts in both experiments and often increased yield slightly, though effects were not always statistically significant. Yield loss: yield loss per whitehead did not differ among seeding rates. In the5 seding rate trial, Dermacor improved yields at intermediate plant densities but not at the lowest and highest densities. At LSU, A field trial using two seeding rates (39 and 196 kg/ha) showed that higher plant densities produced fewer whiteheads per m² and higher yields. Both seeding rate and insecticide treatment significantly affected whitehead numbers. Yield was driven primarily by seeding rate, although insecticide-treated plots tended to have slightly heavier grains and marginally higher yields. Overall: Seeding rate and stand density play a major role in stem borer injury and can complement chemical control programs. Overall Accomplishments Identified reproductive stages as the most susceptible periods for SCB and MRB attack. Demonstrated that varietal resistance (particularly in Jupiter and Cheniere) reduces oviposition, boring success, and adult emergence. Established that insecticide applications should target early reproductive stages for maximum whitehead suppression. Quantified how seeding rate influences whitehead density, yield loss, and insecticide performance. Started to generatedatasets supporting development of a degree-day model for stemborer forecasting.

Publications

Progress 09/01/23 to 08/31/24

Outputs
Target Audience:Target audience: rice producers/growers, extension agents, scientists Scientific conference of the EntomologicalSociety of America: Entomology Annual Meeting 2024 Rice field day at Texas A&M AgriLife Research, Beaumont, Texas in July 2024 Rice Field Day Student CompetitionJuly 2024 Changes/Problems: Funding was provided in August 2023 but was not used until January 2024 when the graduate student was able to start. This delayed progress on the objectives. What opportunities for training and professional development has the project provided? Graduate student has received training in field operations of the rice crop from planting to harvesting. Collected research data and learnt to use statistical software such R. Graduate student has participated in field days, thereby interacting with rice stakeholders. How have the results been disseminated to communities of interest?Until August 2024, thegraduate student has participatedin a Rice Field Day at the Texas AgriLife Research Center at Beaumont. What do you plan to do during the next reporting period to accomplish the goals? Continue collaborating with LSU to progress this project by having Zoom meetings and discussions during field days and conferences. Continue mentoring the graduate student in presenting her data at scientific conferences and future field days.

Impacts
What was accomplished under these goals? In a few sentences, what is the issue or problem that your project addresses (i.e.; what are you trying to help solve, fix, mitigate, improve?) The Mexican rice borer (MRB) hasemerged as an important pest of rice along theGulf Coast (southwestern Louisiana and eastern Texas). The current management program for thisinsect is unsustainable because it relies almost exclusively on a single insecticidal seed treatment. Who or what will be most immediately helped by your work, and how? (Hint: What audience did you originally intend for your work to impact?) Rice producers/growers in Texas and Louisiana For each major goal listed in your project initiation form (shown at the top of the screen), describe for this reporting period: For Objective 1: This no-choice experiment aims to characterize the relationship between the plant growth stage and the insect's ability to complete its life cycle, as well as the time required for each developmental phase. In addition, Whitehead symptoms development, measuring the incidence and how fast the whitehead formation happens across the three rice varieties at each growth stage to identify which variety and stage combination shows the highest susceptibility to damage.Progress made in objective1a by conducting the Year 1 of two years of greenhouse experimentsto evaluate the susceptibility of three different rice varieties at four distinct growth stages (mid-tillering, panicle differentiation, booting, and heading)to infestation and damage by the Mexican rice borer.The analysis of the mean number of whiteheads for each rice variety across different growth stages (Heading, Panicle, and Booting) using ANOVA revealed no significant differences. For the Heading stage, the p-value was 0.0915, indicating a trend toward differences between varieties, but it did not meet the conventional significance threshold of 0.05. At the Panicle stage, the p-value was 0.84, and at the Booting stage, the p-value was 0.116, both of which suggest no significant differences in the number of whiteheads among the varieties. These results indicate that, in this experiment, the rice varieties (PVL03, Jupiter, and CL111) did not exhibit significant variation in their susceptibility to MRB infestation across the tested growth stages. For Objective 3: Progress made; Year 1 of two years. A field experiment was used to investigate the impact of different seeding rates on the incidence of whiteheads and subsequent yield loss in rice crops in Texas. This study compares two rice varieties, Cheniere and Jupiter, cultivated in Beaumont and Eagle Lake locations, respectively. The experiment is designed as a 5x2 factorial, encompassing five seeding rates (35, 70, 105, 140, and 175 lb/acre) and two insecticide treatments (Dermacor X-100 treated and untreated plots). Then we analyzed the effect of seeding rates on the percentage of yield loss and identify any correlations between whitehead density and yield reduction. Analysis of variance (ANOVA) indicated that the interaction between seeding rates and insecticide treatments was significant (p = 0.05). When comparing the levels of insecticide treatments, the results showed that control plots had a higher mean number of whiteheads compared to the plots treated with Dermacor. This suggests that Dermacor effectively reduced Mexican rice borer damage.In addition, the analysis demonstrated that seeding rate was the only significant variable affecting mean yield. During the first year, lower seeding rates corresponded with lower yields, while higher seeding rates were associated with increased yields. In contrast, at higher seeding rates (105, 140, and 175 lb per acre), control plots showed slightly lower whitehead counts but without significant yield differences. This trend suggests a potential yield plateau at higher seeding rates, potentially due to resource competition or shading effects caused by denser foliage, which limits light penetration and impacts growth. Describe the key outcomes or other accomplishments realized. In a few sentences, what did your project do about this issue/problem during this reporting period? (HINT: Revisit your logic model's inputs, outputs, and outcomes to describe accomplishments) For objective 1: Conducted first year of greenhouse experiment to characterize the relationship of rice plant age/stage to susceptibility to MRB oviposition. Proposal presented at the Student Competition of the 2024 Rice Field Day at Texas AgriLife Research Center in July (won second place). For Objective 3: Conducted first year of multilocation field experiments to determine relationship of MRB density in yield loss. Presented this research during the 2024 Rice Field Day at Texas AgriLife Research Center in July.

Publications