Oviposition Preference of the Mexican Rice Borer (Lepidoptera: Crambidae) on Conventional and Bioenergy Crops

The Mexican rice borer, Eoreuma loftini (Dyar), is a serious pest of sugarcane, rice, corn, and sorghum, and also threatens production of related bioenergy feedstocks in the Gulf Coast region. A greenhouse study was conducted to determine oviposition preference of E. loftini in cultivars of sugarcane (HoCP 04-838 and HoCP 85-845), energycane (L 79-1002 and Ho 02-113), high-biomass sorghum (ES 5200 and ES 5140), and sweet sorghum (M81E) represented at two phenological stages (immature and mature). Oviposition events occurred exclusively on dry leaf material, although differences in the abundance of events were not detected across treatments. Abundance of eggs per plant was significantly greater in the mature phenological stage, increasing 2.3-fold when compared to egg abundance on immature plants. The number of eggs per oviposition event was impacted by phenological stage, increasing 2.4-fold in mature plants. These results suggest that differences in oviposition preference in E. loftini do not occur between conventional and bioenergy cultivars of sugarcane and sorghum, and that preference is impacted more by plant maturity and abundance of dry leaf material.