Determination of weed competition critical period in red beet
Lithuanian Institute of Horticulture, LT-54333 Babtai, Kauno 30, Kaunas distr.,e-mail: email@example.com
The field experiment was conducted at the Lithuanian Institute of Horticulture from 2000-2002 to determine the critical period of weed competition in red beet (Beta vulgaris L.) hybrid ‘Pablo’ crop. Weeding was delayed until 2, 4, 6, 8, 10, 12 weeks after red beet germination (WAG) and was carried out during the first 2, 4, 6, 8, 10, 12 WAG. Weed competition during the first 10 to 12 WAG reduced the marketable yield of red beet by 100%. Competition in the first 8 WAG reduced yield by 92.2%. Competition in the first 2 WAG had no adverse effect on yield; there was only an 8.3% reduction of red beet yield. A period of weeding for 4 WAG provided a yield similar to that achieved with 6 weeks of weeding. It is concluded that the first 4 WAG are the most critical for weed competition in red beet crop at a 5% yield loss level. Weeds emerging later do not appear to be detrimental to red beet growth and marketable yield.