Eoreuma

Ely, 1910

Eoreuma is a of in the Crambidae, first described by Ely in 1910. The genus contains 11 described , with Eoreuma loftini (Mexican rice borer) being the most economically significant. This species is a major agricultural pest of , rice, sorghum, and corn in the southern United States and Mexico, causing substantial yield losses through larval tunneling in stalks. The genus is to the Americas, with several species described from the southwestern United States and Mexico.

Eoreuma densellus by (c) Victor Engel, some rights reserved (CC BY), uploaded by Victor Engel. Used under a CC-BY license.

Eoreuma by (c) Victor Engel, some rights reserved (CC BY), uploaded by Victor Engel. Used under a CC-BY license.

Eoreuma densellus P1620872a by
xpda. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Eoreuma: //iːoʊˈruːmə//

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Identification

Eoreuma are small to -sized crambid . typically have to buff-colored with subtle patterning. The Mexican rice borer (E. loftini) can be distinguished from similar stalk-boring crambids such as Diatraea saccharalis ( borer) by morphological features of the adult and larval stages; E. loftini have conspicuous round or black spots on most body , while mature larvae show lighter or absent spots. Accurate species identification within the requires examination of and reference to original species descriptions.

Images

Distribution

The Eoreuma occurs in the Americas. Eoreuma loftini is to Mexico and has expanded its range into the United States, first detected in southern Texas in 1980, then southwestern Louisiana in 2008, and central Florida in 2012. Other in the genus have been described from Arizona (E. arenella) and Texas (E. callista, E. confederata, E. crawfordi, E. evae).

Host Associations

Poaceae (grasses) - Eoreuma loftini feeds on (Saccharum officinarum), rice (Oryza sativa), sorghum (Sorghum bicolor), corn (Zea mays), and non- grasses
Lydella jalisco - , solitary of larval stages; first recorded in Nayarit, Mexico in 2022-2023 with 34.4% rate
Allorhogas pyralophagus - imported for ; parasitized up to 65.6% of fifth- and sixth- in field evaluations
Alabagrus stigma - ; parasitized >5% of available E. loftini in field enclosures
Goniozus natalensis - ; parasitized >5% of available E. loftini
Mallochia pyralidis - , from Mexico
Pediobius furvus - Eulophid ; searching studied in
Cotesia flavipes - ; development studied in E. loftini with evidence of developmental disruption

Behavior

Male Eoreuma loftini exhibit stereotyped courtship behaviors including fanning, curling, and attempted copulation when exposed to extracts from female , indicating chemical communication mediates mate recognition. The response is dose-dependent and specific to extracts from sexually mature females.

Ecological Role

Eoreuma loftini functions as a significant agricultural pest in grass . Its larval tunneling activity damages plants and increases susceptibility to stalk rot and . The serves as a host for multiple species, supporting local agent . Its range expansion in the United States provides a model for studying landscape-wide pest management across multiple crop systems.

Human Relevance

Eoreuma loftini (Mexican rice borer) is a major economic pest causing substantial yield losses in , rice, and sorghum. Estimated potential losses exceed $40 million annually for rice and $200 million for sugarcane in Louisiana alone under worst-case scenarios. Management relies on (particularly chlorantraniliprole), early planting, varieties, and agents. traps are used for early . The is difficult to control with contact insecticides due to larval boring .

Similar Taxa

Diatraea saccharalis (sugarcane borer)Similar stalk-boring crambid with overlapping range and distribution; E. loftini distinguished by larval spotting pattern and greater enabling northern range expansion
Diatraea grandiosella (southwestern corn borer)Closely related stalk-boring crambid with similar biology and plants; E. loftini has faster time and different
Elasmopalpus lignosellus (lesser cornstalk borer)Both are stalk-boring in grass , but E. lignosellus feeds in silken tunnels covered with soil particles and has prominent transverse reddish- rather than round spots