Mexican Rice Borer (Eoreuma loftini) Pheromone Trap Efficacy and Role in Invasive Species Monitoring and Pest Management

Abstract

The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an invasive pest of sugarcane, Saccharum spp.; rice, Oryza sativa; and other graminaceous crops along the U.S. Gulf Coast. Identification of E. loftini sex pheromones led to the development of pheromone baited traps. Studies were conducted to determine strategies for the use of E. loftini pheromone traps in invasive species monitoring and pest management. A two-year field study demonstrated that E. loftini pheromone traps attract males from distances of up to 100m. A behavioral assay observed that detection of the pheromone by E. loftini males occurs at ≈48m from the source. A network of pheromone traps monitored E. loftini range expansion from 2009–2015. Eoreuma loftini is now present in nine Louisiana Parishes: Calcasieu, Cameron, Beauregard, Allen, Jefferson Davis, Acadia, Vermilion, Evangeline, and St. Landry. Crop surveys observed E. loftini infesting Louisiana rice and sugarcane. The E. loftini population is advancing eastward at 11 km/yr. The population is characterized by high density clusters and may be limited at higher latitudes. E. loftini is causing substantial yield reductions in unprotected commercial rice fields in southwestern Louisiana. Rice which received the Dermacor X-100® (chlorantraniliprole) seed treatment sustained reduced injury. Pheromone trap captures are correlated to larval infestations in adjacent unprotected rice fields. Infestations of E. loftini in Louisiana sugarcane have not reached damaging levels. Sugarcane infested with E. loftini is being transported to sugar mills east of the pest’s known range, however, it has not established in these regions. Studies indicated automated E. loftini pheromone trapping systems have potential to further reduce scouting efforts. This represents the first use of automated pheromone-based monitoring systems for Lepidopterous insect pests in field crops. Field studies indicate new diamide chemistries may improve chemical control of E. loftini in sugarcane. This research expands the use of E. loftini pheromone traps in invasive species monitoring and pest management. Continued monitoring of E. loftini range expansion and the use of pheromone trap-based scouting techniques should be further pursued to mitigate the impact of this pest along the U.S. Gulf Coast.