title: Evaluating the non-rice host plant species of Sesamia inferens (Lepidoptera: Noctuidae) as natural refuges: resistance management of Bt rice.
abstract: Although rice (Oryza sativa L.) lines that express Bacillus thuringiensis (Bt) toxins have shown great potential for managing the major Lepidoptera pests of rice in southern China, including Sesamia inferens, their long-term use is dependent on managing resistance development to Bt  toxins in pest populations. The maintenance of "natural" refuges, non-Bt expressing plants that are hosts for a target pest, has been proposed as a means to minimize the evolution of resistance to Bt toxins in transgenic plants. In the current study, field surveys and greenhouse  experiments were conducted to identify host plants of S. inferens that could serve as "natural" refuges in rice growing areas of southern China. A field survey showed that 34 plant species in four families can be alternative host plants of S. inferens. Based on injury level under  field conditions, rice (Oryza sativa L.); water oat (Zizania latifolia Griseb.); corn (Zea mays L.); tidalmarsh flatsedge (Cyperus serotinus Rottb.); and narrow-leaved cat-tail (Typha angustifolia Linn.) were identified as the primary host plant species of S. inferens. Greenhouse experiments  further demonstrated that water oat, corn, and narrow-leaved cat-tail could support the survival and development of S. inferens. Interestingly, greenhouse experiments showed that S. inferens preferred to lay eggs on tidalmarsh flatsedge compared with the other three nonrice host species, although  no pupae were found in the plants examined in field surveys. Few larvae were found to survive on tidalmarsh flatsedge in greenhouse bioassays, suggesting that tidalmarsh flatsedge could serve as a "dead-end" trap crop for S. inferens, but is not a candidate to serve as natural  refuge to maintain susceptible S. inferens. Overall, these results suggest that water-oat, corn, and narrow-leaved cat-tail might serve as "natural refuge" for S. inferens in rice planting area of southern China when Bt rice varieties are planted.
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, PR China.
authors.forename: Zhuorong
authors.initials: Z
authors.lastname: Liu
authors.forename: Yulin
authors.initials: Y
authors.lastname: Gao
authors.forename: Ju
authors.initials: J
authors.lastname: Luo
authors.forename: Fengxiang
authors.initials: F
authors.lastname: Lai
authors.forename: Yunhe
authors.initials: Y
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fu
authors.forename: Yufa
authors.initials: Y
authors.lastname: Peng
mesh_terms: D000818:Animals; D001426:Bacterial Proteins; D005260:Female; D006790:Host-Parasite Interactions; D007300:Insect Control; D019476:Insect Proteins; D007305:Insecticide Resistance; D007814:Larva / Q000502:physiology; D008297:Male; D009036:Moths / Q000502:physiology*; D012275:Oryza / Q000469:parasitology; D010058:Oviposition; D010944:Plants / Q000469:parasitology*; D030821:Plants, Genetically Modified / Q000469:parasitology; D011679:Pupa / Q000254:growth & development; D011956:Receptors, Cell Surface
chemical_list: D001426:Bacterial Proteins; C095416:Cry toxin receptors; D019476:Insect Proteins; D011956:Receptors, Cell Surface