Dissertation

In the southeastern United States, the rice water weevil, Lissorhoptrus oryzophilus, is anearly season pest and also the most destructive insect pest of rice. Feeding by adults generallydoes not result in economic injury, but root pruning by larvae can severely reduce both thegrowth and yield of rice (Smith, 1983; Zou et al., 2004). In Louisiana, yield losses typicallyexceed 5 to 10% and can approach 25% or more (Stout et al., 2000). Induced resistance using aknown elicitor of plant resistance, jasmonic acid, and another herbivore, the fall armyworm(Spodoptera frugiperda) was investigated in greenhouse and small-plot field experiments. Bothtreatments induced resistance in rice, and represent the first successful field-based application ofjasmonic acid to reduce populations of an insect pest of O. sativa.The rice stink bug, Oebalus pugnax, is the most important late season insect pest of ricein Louisiana. Broad-spectrum pyrethroid and organophosphate insecticides are commonly usedfor control of the rice stinkbug, although more selective neonicotinoid insecticides are beginningto be registered. Despite its significance as a pest, no non-chemical control methods have beenimplemented in production farms, and as a result, insecticides are the only control methodfarmers utilize.Stink bugs are characterized by the production of large quantities of strong smelling andirritating defensive chemicals which are released from metathoracic glands (MTG) when thebugs are disturbed (Aldrich, 1988). Numerous studies have attested to their efficacy as adefensive response towards predators (Aldrich, 1988; Krall, et al. 1999; Staddon, 1979). Theymay also serve as alarm pheromones (Kou et al., 1989). Furthermore, studies have shown thatmale-produced pheromones are exploited by natural enemies (Aldrich et al., 1984; Aldrich,1985; Aldrich et al., 1986; Hokkanen and Pimentel, 1989) and may help protect againstentomopathogens (Sosa-Gomez et al., 1997; Milks and Hamm, unpublished). The multi-2