Associations between host plant concentrations of selected biochemical nutrients and Mexican rice borer, Eoreuma loftini, infestation

Authors: Showler, Allan; Moran, Patrick

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2014
Publication Date: 4/10/2014
Citation: Showler, A., Moran, P.J. 2014. Associations between host plant concentrations of selected biochemical nutrients and Mexican rice borer, Eoreuma loftini, infestation. Entomologia Experimentalis et Applicata. 151(2):135-143.

Interpretive Summary: The Mexican rice borer is an economic pest of sugarcane and other grassy crops and weeds, but its relationship with plants is not well understood. In this study, host plants (i.e., barnyardgrass, broadleaf signalgrass, johnsongrass, Vasey's grass, sudangrass, a hybrid forage crop, corn, sorghum, and sugarcane) were analyzed for nutritional biochemicals that might make some host plant species more preferable for development than other host plant species. We found that plant species with relatively high levels of fructose were consistently associated with elevated levels of Mexican rice borer infestation. This study is the first to link a nutritional property of host plants with levels of Mexican rice borer infestation.

Technical Abstract: The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an economic pest of sugarcane and other graminaceous host crops, and it attacks grassy weeds. Oviposition preference has been known to be for plants with leaves that form folds. This study is the first to associate the nutritional quality of crop, weed, and forage plant hosts with Mexican rice borer injury. Three experiments were conducted to determine the levels of selected biochemical nutrients, including free amino acids and sugars, in four grass weeds [barnyardgrass, Echinochloa crus-galli (L.); broadleaf signalgrass, Urochloa platyphylla (Munro ex C. Wright); johnsongrass, Sorghum halepense (L.) Pers.; and Vasey's grass, Paspalum urvillei Steud.] and a forage grass [sudangrass, Sorghum bicolor (L.) Moensch spp. drummondi (Nees ex Steud.) de Wet & Harlan], three crop species (corn, Zea mays L.; sorghum, Sorghum bicolor Moench; and sugarcane, Saccharum spp.), and a sorghum-sudangrass forage hybrid. Of 16 free amino acids detected among plants in the first two experiments, only high accumulations of free histidine in sudangrass and corn were consistently associated with increased infestations by Mexican rice borer larvae. In all three experiments, high levels of fructose were consistently associated with heightened Mexican rice borer infestation. Ramifications of these findings on the potential dispersal of this invasive pest in the United States and possible applications of fructose in baits are discussed.