THE PRE-em USE OF SOME HERBICIDES IN THE CONTROL OF WEEDS IN POTATOES AND THEIR INFLUENCE ON THE YIELD

In order to mitigate the problem with weeds in the potato crop in the 2017 growing season in the towns Bogovinje-Tetovo (Polog region), a field experiment was established according to the randomized block system with three replications with experimental plot sizes of 21 m2. In the experiment, we investigated the structure of weeds, the degree of appearance, the efficacy of herbicides and the eventual phytotoxicity of the herbicides used. The potato planted was the cultivar "Silvana" and the following treatment variants were included: pendimetalin 5 l/ha, linuron 2.5 l/ha, metobromuron 3 l/ha, metobromuron 4 l/ha, metribuzin 0.75 kg/ha PRE-em, metribuzin 1 kg/h PRE-em, mechanical controls and absolute controls. From the obtained results, it was found that the structure of weeds consists of 9 types of weeds, of which 3 species from the group of monocotyledonous weeds and 6 species from the group of dicotyledonous weeds. The number of weeds was 126 plants/m2. The dominant weeds were Echinochloa crus-galli with 93.7 plants/m2, Polygonum lapathifolium with 10.0 plants/m2, and Polygonum aviculare with 9.3 plants/m2. The efficiency of herbicides in the fight against dicotyledonous weeds has been from 97.7-100%, monocotyledonous weeds from 95.8-98.2%, while the overall efficiency without geophytes has been from 96.8-98.4%. Regarding phytotoxicity in the potato culture, no signs of phytotoxicity were observed in any variant of the treatment.