HERBICIDAL CONTROL OF Lantana camara

Lantana is a perennial shrub that commonly infests pastures, roadsides, and natural areas. In Florida (USA), lantana flowers approximately 10 months of the year and is a prodigious seed producer. Though seed viability is reportedly low, lantana is most common in areas where birds roost: abandoned citrus groves, under power lines, along highway guard rails, etc. Many experiments have been conducted to manage this weed, but few successful herbicides have been found. In particular, foliar applications of triclopyr results in essentially no injury symptoms or reduction of lantana growth. However, little information is available for the effectiveness of fluroxypyr, aminopyralid, or aminocyclopyrachlor. Experiments were conducted in central Florida on a dense, natural infestation of lantana. Plots measured 8 meters by 16 meters and were replicated 4 times. Herbicides were applied in water at 230 L/ha. Aminopyralid (0.12 kg/ha), fluroxypyr (0.55 kg/ha), and aminocyclopyrachlor (0.2 kg/ha) were applied in the fall, approximately 2 months prior to frost. Half of the plots treated with each herbicide were re-treated the following spring (approximately 6 months later). Therefore, data consist of each herbicide applied in the fall alone as well as fall followed by spring. Aminopyralid was ineffective on lantana, either one or two applications resulted in 20% control one year after treatment (YAT). Fluroxypyr applied once resulted in 12% control at 1 YAT, but the two application treatment resulted in 80% control after one year. The combination of fluroxypyr + aminopyralid, applied twice, resulted in approximately 90% control 1 YAT. A single application of fluroxypyr + aminopyralid failed to provide greater than 20% control. Conversely, aminocyclopyrachlor applied once in the fall provided 98% lantana control at 1 YAT. Where aminocyclopyrachlor was applied twice, lantana control was 100%. From these data, lantana can be effectively controlled by two applications of fluroxypyr, two applications of fluroxypyr + aminopyralid, or a single application of aminocyclopyrachlor.