2 GRASS HERBICIDES FOR PINEAPPLE FIELDS

Two field experiments (plant and ratoon crops) were conducted at Vega Baja and Barceloneta Land Authority pineapple farms in 1990 and 1991 t o evaluate two grass herbicides. Fluazifop-p-butyl at 0.28 and 0.56 kg ai/ha and quizalofop at 0.224 and 0.448 ai/ha were applied postemerge nce twice to the 12-month-old plant crop and twice to 30-month-old rat oon pineapple plants. Two methods of application (over the top and dir ected spray) were used. Both herbicides gave excellent control of all grasses with no apparent crop injury. In the plant crop experiment, th e highest fruit yield was obtained with quizolofop at 0.224 kg ai/ha a pplied over the top (69,289 kg/ha). This treatment differed significan tly in yield with three of the other herbicide treatments. In the rato on crop experiment, the highest pineapple yield was obtained with flua zifop-p-butyl at 0.56 kg ai/ha applied as directed spray (51,585 kg/ha ). This treatment did not differ significantly with all other treatmen ts.