CRANBERRY YIELD AND FRUIT-QUALITY REDUCTION CAUSED BY WEED COMPETITION

The relationships between canopy density of three perennial weed speci es (Potentilla pacifica Howell, Aster subspicatus Nees, and Lotus corn iculatus L.) and 'Mcfarlin' and 'Stevens' cranberry (Vaccinium macroca rpon Ait.) yield and fruit quality were evaluated. Yield was more seve rely affected by weed interferences than fruit size or color. Best-fit regression equations for the effects of weed density on yield, fruit size, and color were linear or quadratic polynomials with a strong lin ear component. For each bog, the slope of the linear relationship betw een yield and weed density was more negative as the mean yield of weed -free controls increased. 'Stevens' fruit size and yield were more sen sitive and fruit color was less sensitive to changes in P. pacifica po pulation density than those of 'McFarlin'.