Bristly starbur (Acanthospermum hispidum) interference in peanuts (Arachis hypogaea).
The effects of bristly starbur (A. hispidum) interference with groundnuts were studied from 1980-83 on a Dothan sandy loam (Plinthic Paleudults). Groundnut seed yields, which included seed + hulls, were reduced as bristly starbur densities increased from 2 to 64 plants/7.5 m of row. Full-season interference from 8, 16, 32 and 64 bristly starbur plants/7.5 m of row reduced groundnut seed yields 14, 26, 43 and 50%, resp. The seed yield of groundnuts maintained weed free for 6 weeks after crop emergence was reduced by no more than 3% compared to groundnuts maintained weed free for the entire season. Weed interference for 2 weeks after crop emergence reduced seed yield by an average of 4% over the 3-year period, based on prediction equations. Bristly starbur interference for 13 weeks after crop emergence reduced groundnut forage DW yield by 54%. Similarly, groundnut interference for 13 weeks after emergence reduced bristly starbur forage DW yield by 32%. Bristly starbur density in the forage DW studies averaged 35/7.5 m of row. These bristly starbur were confined to a 35-cm band over the drill. Groundnut density averaged 72/7.5 m of drill.