Abstract

The study was conducted at

Los Diamantes Experiment Station, located in Guapiles,

Costa Rica, to compare four sowing densities of thornless

palms and two weed management strategies (chemical and

physical) on weed population dynamics of this crop, during

the first year of growth. Weed cover and height, species

present and herbicide damage were among the variables

recorded. Soil tillage prior to the crop establishment

promoted weed germination from the seed bank. A total of

31 weed species were recorded from a 3452 m2 experimental

area during the first 14 months after sowing. An interaction

between sowing distance and weed management strategies

was determined for gramineus and broadleaf species.

Paspalum fasciculatum was the dominant species in plots

under hand weeding while Ageratum conyzoides prevailed in

glyphosate treated plots. Nine months after sowing, weed

height and cover along crop rows or between them were

different depending on the sowing density. In general,

chemical weed control was efficient, although care should be

taken during the first spraying when crop and weed height are

similar, to avoid crop damage.