Insect surveys taken during 1984-1986 in Ashland and Bayfield Counties of northern Wisconsin revealed that several potential insect pest species were common in birdsfoot trefoil, Lotus corniculatus. Three plant bug species, including: the tarnished plant bug, Lygus lineolaris: alfalfa plant bug, Adelphocoris lineolatus; and Plagiognathus chrysanthemi were abundant in most sampled fields. P. chrysanthemi was the most abundant species, was only present in the northern locations, and completed one generation per year. A. lineolatus and L. lineolaris were second and third in abundance, respectively, and completed two generations per year. Population levels of the potato leafhopper, Empoasca fabae. exceeded a combined total of 45 nymphs and adults per sweep in a southern Wisconsin location but were uncommon in northern Wisconsin. Present, but less abundant, were the trefoil seed chalcid, Bruchophagus platypterus; meadow spittlebug, Philaenus spumarius; and pea aphid, Acyrthosiphon pisum, all occurring at densities of less than one insect per sweep.
Wipfli, Mark S.; Wedberg, John L.; Hogg, David B.; and Syverud, Thomas D.
"Insect Pests Associated With Birdsfoot Trefoil, Lotus Corniculatus, in Wisconsin,"
The Great Lakes Entomologist: Vol. 22
, Article 4.
Available at: http://scholar.valpo.edu/tgle/vol22/iss1/4