Mexican rice borer (Lepidoptera: Crambidae) oviposition preference and larval performance on primary non-crop hosts

Expanding its range from Mexico into Texas, the Mexican rice borer, Eoreuma loftini (Dyar), was detected in Louisiana in 2008. E. loftini is a severe pest of sugarcane and rice, but it also infests a wide range of grasses. Management research has focused on field crops, with the role of infestations in non-crop grasses only recently receiving consideration. A greenhouse experiment was conducted to quantify E. loftini ovipositional preference and larval performance on primary non-crop grasses observed hosting this borer during seasonal sampling near southeast Texas rice fields. Two perennial grasses (Sorghum halepense and Paspalum urvillei) at three phenological stages and two annual grasses (Lolium spp. and Bromus spp.) at two phenological stages were studied. An annual crop grass, rice at three phenological stages, was used as a standard in this experiment arranged as a randomized complete block design with cages as blocks. Fourteen mated E. loftini females were released in each cage, and three days after, each plant was inspected for assessment of oviposition. Upon pupation of >90% of sentinel E. loftini larvae, larval performance was assessed, dissecting all plants for larvae and pupae. Association of plant characteristics with preference and performance will be discussed, as well as the implications of this study in the development of an E. loftini population simulation model.