Postemergence Control of Phyllanthus urinaria by Prodiamine and Phytotoxicity to Ornamentals
Postemergence control of Phyllanthus urinaria L. (chamberbitter) in nursery and landscape plantings has been primarily limited to hand-weeding. Prodiamine was evaluated for postemergence control of chamberbitter and phytotoxicity to containerized ornamentals. On 20 June 1995, prodiamine at 0, 1.68, 3.36, or 6.72 kg a.i./ha was applied over-the-top to immature chamberbitter growing in 3.8-L containers of established Buddleia davidii Franch. `White Bouquet' Cuphea hyssopifolia HBK. `Desert Snow', Lantana camara L. `Irene', and Lantana montevidensis (Spreng.) Briq. `Lavender Weeping'. Weed-free checks were included. Applications were made with a compressed air backpack sprayer. There were four replications per treatment placed in a randomized complete block design by species. Plants were established and maintained on a container bed under full sun and overhead irrigation. Growth of and phytotoxicity to the ornamentals species, and percent coverage and number of chamberbitter, were recorded periodically for 14 weeks after treatment (WAT). Chamberbitter shoots were harvested for dry weight analysis 14 WAT. Prodiamine provided some postemergence control of chamberbitter. However, Cuphea and both Lantana species exhibited leaf distortion and/or delayed flowering.