WEED-CONTROL ECONOMICS IN BELL PEPPER (CAPSICUM-ANNUUM) WITH NAPROPAMIDE AND HAND WEEDING

Field studies were conducted in 1990 and 1991 at Davis and Five Points , CA to evaluate weed control with napropamide and hand-weeding and th e effect on yield and profitability in transplanted bell pepper. Weed cover 8 wk after transplanting averaged less than 10% in plots hand-we eded biweekly for 6 wk after transplanting. Weed cover at harvest was less than 30% in plots hand-weeded at 8 wk after transplanting. Naprop amide treatment reduced weed cover at 8 wk after transplanting an aver age of 34% compared to untreated plots, but differences declined to 14 % at harvest. Time required to hand-weed plots was greater if the inte rval between weeding was 4 instead of 2 wk. The time needed to hand-we ed plots was reduced from 38% to 71% by napropamide treatment. When we eds were excluded by hand-weeding for the entire season, bell pepper y ielded 25 810 kg/ha and was 4% to 18% higher than other treatments. Ne t returns were greater for plots that were hand-weeded the entire seas on or when napropamide was combined with hand-weeding at 4 and 8 wk af ter transplanting, compared to other treatments. Nomenclature: Napropa mide, N,N-diethyl-2-(1-naphthalenyloxy)propanamide; bell pepper, Capsi cum annuum L. 'Jupiter.'