<p> The rice stink bug, <i>Oebalus pugnax</i>(F.), is an important late season pest of rice that is noted for causing grain yield and quality reductions in the United States. This study investigated rice injury using field cages in two rice cultivars ('Cocodrie' and 'Wells') at bloom, milk, and soft dough stages and <i>O. pugnax</i> ecology in the Delta Region of Mississippi. </p><p> Specific objectives were: 1) to determine the impact of adult <i> O. pugnax</i> infestation on rice yield and grain quality at bloom, milk, and soft dough stages of rice development; 2) to determine the impact of adult <i> O. pugnax</i> gender and infestation duration on rice yield and grain quality at the milk stage of panicle development; 3) to identify and examine the seasonal abundance and phenology of <i>O. pugnax</i>on non-cultivated host grasses; and 4) to evaluate feeding preference and development of <i> O. pugnax</i> on host grasses. </p><p> Rice injury increased as <i>O. pugnax</i> density increased. The bloom and milk stages were the most vulnerable to blank and discolored kernels, respectively. <i>O. pugnax</i> feeding injury was significant after 3 d of infestation duration during the milk stage of panicle development. Female <i>O. pugnax</i> caused a greater percentage of blank kernels compared to males. </p><p> A survey of <i>O. pugnax</i> hosts indicated that Italian ryegrass, <i> Lolium perenne</i> L. ssp. <i>multiflorum</i> and winter wheat, <i> Triticum aestivum</i> L., were important hosts during spring and early summer. Junglerice, <i>Echinochloa colona</i> (L.) Link; crabgrass spp., <i>Digitaria</i> spp. Haller; southwestern cupgrass, <i> Eriochloa acuminata</i> (J. Presl) Kunth; and praire cupgrass, <i> Eriochloa contracta</i> (Hitchc.), were important hosts for <i> O. pugnax</i> during early to mid-summer. Browntop millet, <i>Urochloa ramosa</i>, and broadleaf signalgrass, <i>Urochloa platyphylla</i>, supported adult <i>O. pugnax</i> prior to overwintering. In a choice test of wild host grasses, junglerice was the most preferred over 10 other host grasses. In the no-choice test, mean development time was shorter and survival was greater for <i>O. pugnax</i> nymphs reared on rice, <i> Oryza sativa</i> L., compared to dallisgrass, <i>Paspalum dilatatum </i> Poir and junglerice. These results provide biological and ecological information on which new <i>O. pugnax</i> integrated pest management practices can be developed.</p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:3603416 |
| Date | 15 January 2014 |
| Creators | Awuni, George Agana |
| Publisher | Mississippi State University |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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