Kudzu is an invasive perennial climbing vine characterized by fast growth rates and tolerance to control measures. Repeated applications with high rates of 2,4-D plus picloram provide effective kudzu control, but picloram use is not permitted in certain states due to groundwater pollution concerns. Studies were conducted in Alabama and Florida to compare kudzu control with aminocyclopyrachlor, a new herbicide, to control provided by aminopyralid, clopyralid, metsulfuron methyl, and picloram plus 2,4-D, which are common treatments for kudzu management. Two annual applications of the same herbicide treatment were evaluated for effects on kudzu cover, kudzu volume index, and cover of other vegetation. Aminocyclopyrachlor at 140 to 280 g ae ha⁻¹ (2 to 4 oz ae ac⁻¹) was as effective as the standard 4.48 kg ae ha⁻¹ (4 lb ae ac⁻¹) 2,4-D amine plus 1.2 kg ae ha⁻¹ picloram for kudzu control. There were no differences in kudzu control among the three rates of aminocyclopyrachlor tested. Colonization by graminoids, forbs, and Rubus spp. at 2 yr was greatest for herbicides providing the best kudzu control: aminocyclopyrachlor, and 2,4-D plus picloram. Herbicide treatments were more effective in controlling kudzu at the Alabama location, but repeated annual applications for 2 yr did not completely eliminate kudzu with any treatment at either site.

Nomenclature: 2,4-D; aminocyclopyrachlor; aminopyralid; clopyralid; metsulfuron methyl; picloram; kudzu, Pueraria montana (Lour.) Merr., USDA code PUMOL, EPPO code PUELO.

Interpretive Summary: The new herbicide, aminocyclopyrachlor, applied at 140 to 280 g ae ha⁻¹ controlled kudzu as well as the standard treatment for kudzu management, 4.48 kg ae 2,4-D amine plus 1.21 kg ae picloram, and generally better than the other common kudzu herbicides metsulfuron methyl, aminopyralid, and clopyralid. Graminoids, Rubus spp., and forbs recolonized plots receiving the most effective treatments for kudzu control. Graminoid (grasses, sedges) cover increased following aminocyclopyrachlor treatments, an important consideration for restoration of infestations where kudzu was planted for erosion control in the region. Annual herbicide applications for 2 yr did not eradicate kudzu, confirming the need for multiple years of treatment or more frequent applications.