Table 3. Control of leafy spurge density using biological control and herbicide control strategies.

Strategy Years of control Decrease in leafy spurge density (%) Data source
Biological control 1 67 McClay et al. (1995), Stromme et al. (1996), Lym and Nelson (2000), Kirby et al. (2000), Lym and Nelson (2002), Lym (2005)†
2 76
3 81
4 97
Herbicide control 1 95 Lym and Nelson 2002‡

†The mean percent control was calculated by combining all data sources and attempting to ensure that the experimental conditions were similar.
‡The chemicals and quantities used were Picolarm at 0.56 kg/ha and 2,4-D at 1.1 kg/ha, applied in the fall.