Critical period of weeds interference in pineapple (Ananas comosus [L.] Merr.) crops

Description of the subject. In crop-weed competition, some periods are critical because they may interfere with the crop production capacity. Therefore, knowing these periods is crucial when deciding on the best time for control and preparation of the Integrated Management Program. Objectives. To determine the Period Prior to Interference, Total Period for Interference Prevention, and the Critical Interference Period in pineapple cultivation. Method. The experimental design consisted of randomized blocks in 2 x 15 factorial arrangement, four replications, and two management systems: weeds control and crop-weeds coexistence; 15 increasing periods of 30 days each after planting: 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420. In the control treatments, since planting, manual weeding (with hoe) and mechanical weeding (with brush cutter) were done during increasing periods of time, and in the coexistence treatments, the weeds lived together with pineapple plants and, at the end of each period, weeds control was made with mechanical and chemical weeding. Results. The best yields were achieved in the periods of less coexistence with weeds. The critical periods for interference prevention with 5 and 10% of yield losses were 259 and 204 days, respectively. Conclusions. The critical period for interference prevention lasted 14-259 days after planting of the pineapple offsets.