The objective of this

study was to determine the effect of several management

strategies on the populations of these species. A ten-year-old

banana plantation was chosen for evaluation with the

following treatments: T1 = untreated control; T2= physical

control, T3= successive sprays with glyphosate, T4=

successive sprays with paraquat, T5= successive sprays with

gluphosinate and T6= mixed control based on weed sampling.

Populations of P. zizanoides in rows were reduced 89, 93, 79

and 68% for T3,T4, T5, T6 respectively compared with T1. In

the area next to the banana plant, populations of P.

conjugatum were reduced by 78, 91, 95, 99 and 75% for T2,

T3, T4, T5 and T6 respectively (Duncan; p< 0.05). The results

indicate that treatments with herbicides and mixed control

reduce the populations of these species, while populations of

the untreated and physical control plots remained constant in