We evaluated the effects of snow cover and debris cover on overwintering success of Aphthona from 2001 to 2004 in southeast North Dakota. Chill degree-days, soil temperature, and duration of soil temperatures were monitored in field plots. Emergence of Aphthona from soil cores collected in October and held in the laboratory under simulated winter conditions did not differ across treatments. Fie...

Three trials were conducted to determine if low ingestion of some leafy spurge (Euphorbia esula L.) by sheep is primarily due to differences in sheep or in leafy spurge. In the first trial, pastures in Idaho and North Dakota were grazed by sheep originating from both states. Generally, sheep from both states grazed the leafy spurge growing in the Idaho pastures reluctantly but grazed the leafy ...

Podosphaera (Sphaerotheca) euphorbiae on Euphorbia epithymoides (= E. polychroma, cushion spurge) is reported for the first time in North America. Neoerysiphe (Erysiphe) galeopsidis on Lamium amplexicaule (henbit), Blumeria (Erysiphe) graminis on Festuca idahoenis (Idaho fescue), Taphrina johansonii on Populus tremuloides (trembling aspen), and Taphrina occidentalis on Alnus rubra (red alder) a...