Smaller European Elm Bark Beetle Panel Tests, 1975

Abstract

Plywood panels (15 x 15 cm) were treated with 8 insecticides from June 23-27, 1975, to determine effectiveness in controlling smaller European elm bark beetles attracted to Multilure-baited surfaces. The experiment was a 5 x 3 x 8 factorial design. The treatment factors were 5 chemical concentrations (1, 3, 6, 12, and 18 or 24%; Baygon 1, 3,6, and 12%), 3 beetle exposure times (5, 20, and 60 sec), and 8 bioassay periods (every 2 weeks for 16 weeks). Each combination was replicated 3 times. Concentrations were prepared by serial dilution; 2 ml of each were pipetted onto a 144-cm2 center surface area (1% = 0.14 mg/cm2 ai) of each panel, and were spread evenly with a glass rod. Panels were weathered outside; the mean tempergture was 18°C (range: -1.6 to 34.4°C), and total rainfall was 26 cm during the study. Bioassays were conducted by confining 20 newly emerged beetles between a treated panel surface and an inverted plastic petri dish (15 x 100 mm) for specified lengths of time at appropriate posttreatment intervals. After each exposure, beetles were placed on filter paper in petri dishes, and held in darkness for 24 h at 30 ± 1°C and 92 ± 2% RH before mortality was determined. Mortaility was pooled and averaged for all 3 exposure times at each concentration, because there were no significant differences in mortality among exposure times. LC50 and LC90 values were determined by interpolation.

Insecticides For Control of Bark Beetles That Spread Dutch Elm Disease

“…Studies that compared various insecticides have uniformly concluded that chlorpyrifos and carbaryl were more toxic than methoxychlor to European elm bark beetles (Barger 1978;Page and Green 1978;Rabaglia 1980;Brown and Eads 1982). However, methoxychlor was observed to have a potent repellant effect (Doane 1962) and to be more durable on plywood surfaces than carbaryl and chlorpyrifos (Barger 1978). Lack of complete twig protection in methoxychlor-treated trees was shown to be mainly the result of incomplete coverage (Cuthbert et al 1973).…”