Abstract
Two field weed control experiments with transplanted eggplant (Solanum melongena L.) were conducted at the agricultural substation in Lajas in 1984-85 and one in Juana Díaz (1985). In Lajas (1984) a single postemergence application of either fluazifop-P (R)—2— (4—[5—(trifluoromethyl)— 2—pyridinyl] oxy phenoxy) propanoic acid sethoxydim [2— (1—ethoxyimino) butyl] —5—[2—(ethylthio) propyl—3 hydroxy—2—cyclohexen— 1—one or quizalofop (±2— (4— [(6-chloro— 2-quinoxalinyl) oxy — phenoxy] — propanoic acid) gave excellent (90% or more) control of grasses for 10 weeks after transplanting eggplant. Eggplant yields increased substantially with manual cultivation after the herbicide applications. In a second experiment in Lajas in 1985 excellent 10-week control of grasses was provided by the combination of preemergence DCPA (dimethyl 2,3,5,6— tetrachloro—1, 4— benzenedicarboxylate) at 8.4 kg ai/ha followed by manual weedings, or the postemergence applications of either fluazifop-P (0.28 kg ai/ha), sethoxydim (0.27 kg ai/ha) or quizalofop (0,28 kg ai/ha) 2 weeks after a hand weeding. The highest yield (27,117 kg/ha) was obtained in plots with DCPA application plus 3 manual weedings. In a similar experiment at Juana Díaz (1985) the combination of a manual weeding at 3 weeks plus the postemergence fluazifop-P application at 5 weeks was the only treatment that really controlled grasses during the first 10 weeks. Although the highest crop yield (29,474 kg/ha) at Juana Díaz was obtained in plots with 3 manual weedings without herbicides, statistically comparable yields were obtained in plots with DCPA plus manual weedings at 3 and 5 weeks, with sethoxydim plus one weeding, and with fluazifop plus one weeding.