The control of leafy spurge (Euphorbia esula L.) across the northern tier of the U.S. and southern Canada has largely been ineffective since the plant’s introduction to the continent in 1827. Leafy spurge is currently found in 38 states and all the Canadian provinces except Newfoundland, with infestation levels in the U.S. of approximately 2 million ha. The economic impact in the Dakotas, Montana, and Wyoming was estimated to be $144 million in 1991. However, the introduction of insect biological control agents is having a dramatic impact on the weed. The biological control agents demonstrating the greatest success are Aphthona nigriscutis (Foundras), A. czwalinae (Weise) and A. lacertosa (Rosenhauer). These flea beetles have done more to produce sustained control of leafy spurge in the last 10-15 years than any other control method. This is encouraging given that flea beetle introductions are relatively recent (10-15 years) versus the 176 years leafy spurge has had to establish and spread. This paper outlines the impact of flea beetles on leafy spurge in and around Theodore Roosevelt National Park near Medora North Dakota. Combinations of ground measurements, aerial photographs, and hyperspectral images were used to quantify spatial and temporal changes in leafy spurge populations over a 9-year period (1993-2002). Dramatic reductions in leafy spurge resulting from biological control (90%-95% in some areas) are documented and the methods used to identify and quantify these reductions are presented.
Species 1: Coleoptera Chrysomelidae Aphthona nigriscutis (flea beetle)
Species 2: Coleoptera Chrysomelidae Aphthona czwalinae
Species 3: Coleoptera Chrysomelidae Aphthona lacertosa
Keywords: leafy spurge, biological control
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