Mapping the infestation: Spatial dynamics of Eoreuma loftini (Dyar) in sugarcane

Since the arrival and eastward expansion of Eoreuma loftini (Dyar) in Louisiana, little research has addressed its impact on sugarcane. In the absence of species-specific data, growers and scouts rely on information from the morphologically similar Diatraea saccharalis, despite key behavioral and reproductive differences that may alter management strategies. Scouting remains the primary control method, yet current practices target areas typical of D. saccharalis, with no evidence this is effective for E. loftini. This study investigates the plant- and field-level distribution of E. loftini in commercial sugarcane fields to improve scouting accuracy and management efficiency. Paired resistant (L 01-299) and susceptible (HoCP 14-885) fields will be selected at six locations with known E. loftini activity. Fields are divided into four perimeters, with eight sampling points per perimeter. At each point, 25 stalks will be destructively sampled, recording species presence, bore location, feeding site, and internode damage. Sampling will occur once fields reach ≥5% bored internodes, prior to insecticide application. Data will include binomial and categorical variables and analyzed using generalized linear mixed models (PROC GLIMMIX), with site and year as random effects. ANOVA will compare perimeters. Spatial patterns will be assessed using ArcGIS, with Global Moran’s I and Gi statistics identifying spatial autocorrelation and hot/cold spots. Inverse distance weighting (IDW) will be used to spatially smooth larval density data. Findings will inform targeted scouting and treatment recommendations, improving efficiency and resource use in managing E. loftini in Louisiana sugarcane.