CEREAL LEAF BEETLE OULEMA MELANOPUS SURVEY AND DETECTION IN

MALHEUR COUNTY, OREGON

B.C. Simko


 
 


Cereal Leaf Beetle Oulema melanopus (CLB) has been detected in southwest Idaho since 1997 and 1998 by Idaho Department of Agriculture and University of Idaho entomologist. Oregon Department of Agriculture staff conducted a survey in eastern Oregon during the summer of 1998 but did not detect or report any findings of CLB. In the spring of 1999, between April 15 to May 15, 30 small grain fields were surveyed in Malheur County, Oregon by the author. Fields located within ¼ mile of the Snake River border or the Big Bend, Adrian district border with Idaho were selected for the survey. Sampling of fields was conducted using a standard sweep net taking 2 to 3 sets of 50 straight line sweeps just within field borders. Adult CLB were detected in 19 of the 30 fields surveyed. This is the first confirmed record of CLB in the state of Oregon. In the infested fields, adult counts were relatively low ranging from less than 1 adult per 50 sweeps to 6 adults per 50 sweeps, with an average of 1 to 2 adults per 50 sweeps. Infested host included winter wheat, spring wheat, and spring oats. CLB eggs also were observed in fields south of Nyssa and near Adrian, OR, during the early May sample dates. One field of newly planted alfalfa inter-seeded with spring oats, located south of Adrian, OR had the highest population of adults and eggs. After onset of hatch, larval feeding damage on the oats became conspicuous and severe. Results of the survey were reported to the appropriate staff of the Oregon Department of Agriculture and the USDA APHIS. On June 18 cooperating with the APHIS and ODA survey entomologist, the first releases in Oregon of larval parasite Tetrastichus julis was made at the Adrian alfalfa/spring oat field. ODA and APHIS staff since has detected CLB in several other counties in both eastern and western Oregon. California Department of Food and Agriculture has placed an exterior quarantine for this pest covering shipments of alfalfa grass hay mixtures and other commodities from infested counties of Oregon.
 
 
















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