Site information and field-collected data from a 1-year 100-site survey of leafy spurge (Euphorbia virgata/esula) populations in the northern U.S. Data include: 1) estimates of leafy spurge density and relative prevalence of ramets versus genets; 2) the abundance and composition of Aphthona species complex biological control agents; 3) presence/absence of two additional biological control agents (Oberea erythrocephala and Hyles euphorbiae). Resources in this dataset:Resource Title: Data from: High genetic diversity in the landscape suggests frequent seedling recruitment by Euphorbia virgata (leafy spurge) in the northern U.S.A.. File Name: West et al Leafy Spurge clonality data.csvResource Description: Dataset containing site-level estimates of leafy spurge abundance, clonality, and associated biological control agent communityResource Title: Key for Dataset: High genetic diversity in the landscape suggests frequent seedling recruitment by Euphorbia virgata (leafy spurge) in the northern U.S.A.. File Name: Key for West et al Leafy Spurge clonality data.csvResource Description: This provides information on the data columns included in the associated dataset.