Field trials were carried out to study the effect of weed control periods on some yield components of the peanut crop. Two experiments were carried out in Taquaritinga-SP, Brazil, one during the "dry season" (seeds sown in March), and the other during the "rainy season" (seeds sown in September). The treatments utilized were the following weed control periods: 0-17, 0-31, 0-45, 0-59, 0-73, 17-31, 17-45, 17-59, 17-73, 31-45, 31-59, 31-73, 45-59, 45-73 and 59-73 days after plant emergence. Two controls were used, one without weed control, and the other without weed interference during throughout the crop cycle. The major weed infesting both trials was Digitaria horizontalis. The infesting weed community and crop were affected by the seeding season, altering their interference relationships. In the "rainy season", the effects of the infesting weed community were more drastic, affecting peanut yield more intensely. Among the yield crop components evaluated, the number of pods per plant was the major factor in yield reduction. In the "rainy season" , control was needed only after 45 days of weed interference while in the dry season, only after 59 days, characterizing the critical times prior to interference. In both seeding seasons, weed control carried out up to 17 days after emergence was enough to maintain yield crop, being characterized as the critical weed-free period.
Digitaria horizontalis; competition; interference
