Damage Assessment and Sampling of the Rice Stink Bug
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DAMAGE ASSESSMENT AND SAMPLING OF THE RICE STINK BUG, Oebalus pugnax (FABRICIUS) (HEMIPTERA: PENTATOMIDAE), IN RICE, Oryza sativa L., IN TEXAS A Dissertation by LUIS ESPINO VARGAS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2007 Major Subject: Entomology DAMAGE ASSESSMENT AND SAMPLING OF THE RICE STINK BUG, Oebalus pugnax (FABRICIUS) (HEMIPTERA: PENTATOMIDAE), IN RICE, Oryza sativa L., IN TEXAS A Dissertation by LUIS ESPINO VARGAS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Co-Chairs of Committee, Michael O. Way Jimmy K. Olson Committee Members, L. T. Wilson Edward C. Runge Head of Department, Kevin Heinz August 2007 Major Subject: Entomology iii ABSTRACT Damage Assessment and Sampling of the Rice Stink Bug, Oebalus pugnax (Fabricius) (Hemiptera: Pentatomidae), in Rice, Oryza sativa L., in Texas. (August 2007) Luis Espino Vargas, B.S., Universidad Nacional Agraria La Molina; M.Ag., Texas A&M University Co-Chairs of Advisory Committee: Dr. Michael O. Way Dr. Jimmy K. Olson 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 iv 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. v ACKNOWLEDGMENTS I thank Drs. M. O. Way, J. K. Olson, L. T. Wilson and E. C. Runge for their mentoring, encouragement, advice and friendship. This research would not have been possible without the help of Glenn Wallace, Mark Nunez, Becky Pearson and other staff from the Texas A&M University Agricultural Research and Extension Center at Beaumont. Funding for this research was provided in part by the Texas Rice Research Foundation. vi TABLE OF CONTENTS Page ABSTRACT........................................................................................................... iii ACKNOWLEDGMENTS...................................................................................... v TABLE OF CONTENTS....................................................................................... vi LIST OF FIGURES................................................................................................ viii LIST OF TABLES ................................................................................................. xi CHAPTER I INTRODUCTION............................................................................. 1 II LITERATURE REVIEW.................................................................. 4 Introduction .............................................................................. 4 III RELATIVE SUSCEPTIBILITY OF STAGES OF RICE PANICLE DEVELOPMENT TO RICE STINK BUG: GREENHOUSE AND FIELD EXPERIMENTS............................................................................... 15 Introduction .............................................................................. 15 Materials and Methods............................................................. 17 Results ...................................................................................... 25 Discussion ................................................................................ 40 IV RELATIVE SUSCEPTIBILITY OF STAGES OF RICE PANICLE DEVELOPMENT TO ADULT FEMALE AND MALE RICE STINK BUG FEEDING ................................... 47 Introduction .............................................................................. 47 Materials and Methods............................................................. 48 Results ...................................................................................... 53 Discussion ................................................................................ 58 vii CHAPTER Page V ATTRACTIVENESS OF STAGES OF RICE PANICLE DEVELOPMENT TO RICE STINK BUG....................................... 63 Introduction .............................................................................. 63 Materials and Methods............................................................. 64 Results ...................................................................................... 67 Discussion ................................................................................ 82 VI DETERMINATION OF RICE STINK BUG SPATIAL PATTERN AND DEVELOPMENT OF VISUAL SAMPLING METHODS AND POPULATION SAMPLING PLANS.............................................................................................. 88 Introduction .............................................................................. 88 Materials and Methods............................................................. 90 Results ...................................................................................... 101 Discussion ................................................................................ 117 VII DEVELOPMENT OF SEQUENTIAL SAMPLING PLANS FOR THE RICE STINK BUG .......................................................... 123 Introduction .............................................................................. 123 Materials and Methods............................................................. 125 Results ...................................................................................... 131 Discussion ................................................................................ 139 VIII SUMMARY...................................................................................... 144 Damage Assessment and Sampling of the Rice Stink Bug in Rice in Texas........................................................................ 144 REFERENCES CITED .......................................................................................... 148 VITA ...................................................................................................................... 157 viii LIST OF FIGURES FIGURE Page 3.1 Caged rice plants infested with O. pugnax. Greenhouse experiment 1, 2005. Beaumont, TX ..................................................... 18 3.2 Caged rice plants infested with O. pugnax. Field experiment 2006. Beaumont, TX ............................................................................ 23 3.3 Mean percentage peck of rice infested with O. pugnax during three stages of panicle development ......................................... 35 3.4 Mean percentage peck of rice infested with adult or nymph O. pugnax ................................................................................. 36 3.5 Linear regression between percentage peck and percentage whole kernels of rice infested with O. pugnax during three stages of panicle development. Greenhouse experiment 1, 2005, Beaumont, TX ............................................................................ 39 4.1 Caged rice panicle infested with O. pugnax. Beaumont, TX............... 50 4.2 Mean percentage peck ± SEM in panicles infested with O. pugnax during four stages of panicle development in 2005 and 2006.. ................................................................................ 56 4.3 Mean percentage peck ± SEM in panicles infested with male or female O. pugnax in (A) 2005 and (B) 2006 .......................... 57 5.1 Mean number of O. pugnax ± SEM per location during morning and afternoon inspections for 5 days. Beaumont, TX, 2004............................................................................ 71 5.2 Mean number of O. pugnax ± SEM per location during morning and afternoon inspections for 5 days. Beaumont, TX, 2005...........................................................................