The Biology and Integrated Management of Leafy Spurge (Euphorbia esula) on North Dakota Rangeland

Abstract

Abstract:Leafy spurge, a long-lived perennial, grows in many habitats, from floodplains to grasslands and mountain slopes. The plant emerges in early spring and produces showy, yellow bracts that appear in late May. The true flowers emerge in mid-June. The plant spreads by both seeds and roots and contains a white sticky latex that deters grazing by many animals. Dicamba, 2,4-D, glyphosate, and picloram have commonly been used to control leafy spurge. Picloram plus 2,4-D is frequently used for leafy spurge control in North Dakota. Ten insect species for leafy spurge biocontrol have been released in North Dakota; the most successful have been the flea beetles, Aphthona nigriscutis, A. czwalinae, and A. lacertosa. The leafy spurge gall midge (Spurgia esulae) has been most successful near wooded areas. Herbicides combined with either the leafy spurge flea beetles or gal midge have controlled leafy spurge better than either method used alone. Grazing with sheep or goats is a cost-effective method for controlling leafy spurge top growth in large infestations. Grazing combined with fall-applied picloram plus 2,4-D reduced leafy spurge density more rapidly and maintained control longer than either method used alone. Several grass species are competitive with leafy spurge including 'Rebound' smooth brome, 'Rodan' western wheatgrass, 'Pryor' slender wheatgrass, and 'Manska' pubescent wheatgrass. Cultivating twice each fall after harvest for 3 years in cropland completely controlled leafy spurge. A successful long-term management program should be designed for specific situations and should include combinations of herbicides, insects, grazing, and/or seeding competitive species.

Goat grazing, its interactions with other herbivores and biodiversity conservation issues

“…Compared to other livestock species, goats control spiny or poisonous brush weeds like gorse or poison ivy (Toxicodendron radicans) better than sheep or cattle (Popay and Field, 1996;Celaya et al, 2007). They also control leafy spurge (Lym et al, 1997) better than the other livestock species and, because of their lower dietary overlap with cattle, they might be preferred by cattle rangers over sheep for their mixed herds to reduce the weed enough to allow cattle grazing (Lym, 1998;Olsen and Hansen, 1977). In perennial pastures infested with nodding thistle (Carduus nutans), goats selectively consumed thistle capitula throughout the flowering period and controlled its spread (Holst et al, 2004).…”

Revisiting Leafy Spurge Biocontrol: A Case Study: Cost free management for 16 years!

“…Aphthona fl ava is established but shows a slow population increase. 7 A. nigriscutis was originally the most successful biocontrol agent; 9 however, a mixed population of black beetles, A. czwalinae and A. lacertosa, reproduced and expanded rapidly in the mid-1990s and became the most successful Aphthona species in reducing the leafy spurge. 9,10 Successful establishment of Aphthona is variable along with its effectiveness in controlling leafy spurge across variable habitats in North Dakota.…”

“…7 A. nigriscutis was originally the most successful biocontrol agent; 9 however, a mixed population of black beetles, A. czwalinae and A. lacertosa, reproduced and expanded rapidly in the mid-1990s and became the most successful Aphthona species in reducing the leafy spurge. 9,10 Successful establishment of Aphthona is variable along with its effectiveness in controlling leafy spurge across variable habitats in North Dakota. 7,9,11 Temperature, moisture, soil type, ground cover, slope, and/or associated vegetation at release sites affects fl ea beetle survival and establishment 10,12 with different Aphthona species exhibiting differing preferences to these factors.…”

“…9,10 Successful establishment of Aphthona is variable along with its effectiveness in controlling leafy spurge across variable habitats in North Dakota. 7,9,11 Temperature, moisture, soil type, ground cover, slope, and/or associated vegetation at release sites affects fl ea beetle survival and establishment 10,12 with different Aphthona species exhibiting differing preferences to these factors. 13 Post-establishment monitoring is an important aspect of classical biological control.…”

Restoring tallgrass prairie species mixtures on leafy spurge-infested rangeland

“…Flea beetles reduced leafy spurge densities at some sites in North Dakota, but these reductions did not have a positive effect on grass yields (Kirby and Carlson 1998). Establishment of flea beetle populations has been highly variable in the northern Great Plains and factors responsible for this uneven success have not been identified (Lym 1998).…”