01948nas a2200157   4500008004100000020001400041245013100055210006900186260000900255300001200264490000700276520132500283653003001608100001701638856013501655       2012                        eng d  a0015-404000aOCCURRENCE AND ABUNDANCE OF LISSORHOPTRUS ORYZOPHILUS (COLEOPTERA: CURCULIONIDAE) RELATIVE TO FIELD BORDERS IN CALIFORNIA RICE0 aOCCURRENCE AND ABUNDANCE OF LISSORHOPTRUS ORYZOPHILUS COLEOPTERA  cJune  a445-4530 v953 aField experiments were conducted during 2009 and 2010 on commercial rice fields in the Sacramento Valley of California to validate observations regarding the prevalence of immature populations of the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), near field borders, and to assess their impact on yield. In 5 commercial fields, insecticide-treated and untreated plots were established 4.5, 30 and 60 m from one edge of the field. Soil core samples were collected on 2 dates and inspected for L. oryzophilus immatures. Rice yields were determined by harvesting 15 m2 plots in 2009 or 1 m2 per plot in 2010. Analysis of variance (ANOVA) showed that in most locations, immature populations were higher in plots 4.5 or 30 m from the field's edge than in plots 60 m from the field's edge. Yields from treated and untreated plots did not differ significantly Linear regression of immature populations and rice grain yield per plot per location did not yield a significant, inverse density-yield relationship. Results indicate that border applications of insecticides for L. oryzophilus management are appropriate; however, growers are advised to inspect their fields to confirm border populations and effects on yield. Research needs regarding sampling and economic thresholds are discussed.10aLissorhoptrus oryzophilus1 aEspino, Luis  uhttps://weevil.myspecies.info/occurrence-and-abundance-lissorhoptrus-oryzophilus-coleoptera-curculionidae-relative-field-borders-c