Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), range expansion, biology, ecology, control tactics, and new resistance factors in United States sugarcane

Authors: Showler, Allan; THOMAS, REAGAN - Louisiana State University

Submitted to: American Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/2016
Publication Date: 3/9/2017
Citation: Showler, A., Thomas, R.E. 2017. Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), range expansion, biology, ecology, control tactics, and new resistance factors in United States sugarcane. American Entomologist. 63:36-51. https://doi.org/10.1093/ae/tmx013.
DOI: https://doi.org/10.1093/ae/tmx013

Interpretive Summary: The Mexican rice borer entered the United States in south Texas during the early 1980s and the pest has since then expanded its range to also include regions of east Texas and Louisiana; and in 2012, it was found in weeds in Florida. Until recently, chemical and biological control of the Mexican rice borer failed and were discontinued. During the last 10 years, findings on the pest's ecology have revealed better insecticides and scouting approaches, resistance mechanisms, and cultural tactics. Cultural practices that are in use and are potentially useful, such as careful use of fertilizer, adequate irrigation, avoiding proximity to highly susceptible crops, and enhancement of natural enemy populations, are discussed. Proven and potential mechanisms of sugarcane cultivar resistance involve physiochemical attributes, physical characteristics, and transgenic cultivars. Although limited resistance has been developed against the Mexican rice borer, the mechanisms conferring resistance are poorly understood.

Technical Abstract: Following the establishment of the Mexican rice borer, Eoreuma loftini (Dyar), in the Lower Rio Grande Valley of Texas during the early 1980s, this invasive stalk boring pest expanded its range to include sugarcane- and rice-growing areas of East Texas and Louisiana by 2008; and in 2012 it was documented in noncrop host plants in Florida. From the 1980s until the mid 2000s, attempts to control E. loftini in sugarcane using chemicals and biological control agents failed and both tactics were discontinued; hence, E. loftini infestation of sugarcane was largely unimpeded. During the last decade, research has focused on the pest's ecology, new improved insecticides and scouting methods, sugarcane resistance mechanisms, and cultural tactics. Integrated pest management should involve a range of tactics, including currently registered insecticides that are not being widely used against E. loftini and a scouting method that indicates when larvae are most vulnerable (before they tunnel into the plant) to insecticide sprays. Cultural practices that are in use and the likely utility of other approaches such as plowing under fallow stubble, early planting, judicious use of fertilizer, adequate irrigation, avoiding proximity to E. loftini-susceptible maize cultivars, and enhancement of natural enemy populations (particularly the red imported fire ant, Solenopsis invicta Buren), are discussed. Proven and potential mechanisms of sugarcane cultivar resistance involve physiochemical attributes, physical characteristics, and transgenic cultivars. Although some degree of resistance has been achieved against E. loftini in several sugarcane cultivars, underlying mechanisms are poorly understood.