Interference of Broadleaf Signalgrass (Brachiaria platyphylla) in Peanuts (Arachis hypogaea)

Abstract

Interference studies utilizing natural infestations of broadleaf signalgrass [Brachiaria platyphylla(Griseb.) Nash] in peanuts [Arachis hypogaea(L.) ‘Florigiant′] were conducted at two sites in 1978 and repeated at the same sites in 1979. Full-season interference from broadleaf signalgrass populations of 8, 16, and 1050 plants/10 m of row reduced seed yields 14, 28, and 69%, respectively. Linear regression analysis showed that slightly less than 4 plants/10 m of row significantly reduced yields. Broadleaf signalgrass interference with peanuts for 6 weeks or less after planting did not reduce seed yields; however, interference for 8 weeks or longer after planting did. Peanuts kept weed-free for 6 weeks or more after planting had seed yields equal to peanuts kept weed-free all season. Full-season broadleaf signalgrass interference reduced mature peanut forage yields 64%, but peanut interference only reduced broadleaf signalgrass forage yield 10%.