Vargas, Luis Espino (2009-06). Damage assessment and sampling of the rice stink bug, Oebalus pugnax (Fabricius) (Hemiptera: Pentatomidae), in rice, Oryza sativa L., in Texas. Doctoral Dissertation.
Thesis
Field and greenhouse experiments were conducted from 2003 to 2006 at the Texas A&M University Agricultural Research and Extension Center at Beaumont and commercial rice fields throughout the Texas Rice Belt with the objectives of characterizing the nature of rice stink bug, Oebalus pugnax (Fabricius), damage to rice, Oryza sativa L., and developing visual sampling methods and sequential sampling plans. During 2005 and 2006, in greenhouse and field experiments, rice plants were caged and infested with adult or nymph O. pugnax during the heading, milk or soft dough stage. No differences were found in the weight of rough, brown or milled rice infested with O. pugnax during different stages. More peck was found in grain from plants infested during milk and soft dough than heading. Adult O. pugnax caused more peck than nymphs in all stages. In field experiments conducted during 2005 and 2006, single rice panicles were caged at the onset of heading and infested with one male or female O. pugnax for 48 h during the heading, milk, soft or hard dough stage. No differences were found in the weight of rough rice per panicle infested with O. pugnax. No differences were detected in percentage peck caused by male and female O. pugnax. Infestation during all stages of panicle development produced significantly more peck than no infestation In greenhouse experiments conducted during 2004 and 2005, rice plants at the pre-heading, heading, milk and soft dough stages were caged together and infested with male and female O. pugnax. Insects were observed for a period of five days and their preferences recorded. More insects were observed on milk and soft dough than on pre-heading or heading plants.Commercial rice fields throughout the Texas Rice Belt were sampled during 2003 and 2004 and visual sampling methods were compared to the sweep net method of sampling. Analysis of covariance showed that one sweep of the "long stick" or two sweeps of the "sweep stick" compared favorably to 10 sweep net sweeps. Analyses revealed that visual sampling using the long stick is more cost-reliable than sweep net sampling for O. pugnax in Texas rice fields.
