T. Barakova
Agricultural Academy, 1373 Sofia, Field Crops Institute, 6200 Chirpan, Bulgaria

(Manuscript received 16 June 2023; accepted for publication 29 August 2024)

Abstract. The experiment was conducted during the period 2019-2021 in the experimental field of the Field Crops Institute – Chirpan. The cotton cultivar grown for the purposes of the study was “Viki”. The herbicidal products Bazagran 480 SL /bentazone/ – 1.5 l ha-1, Pendistar 40 SK /pendimethalin/ – 4 l ha-1, Pulsar 40 /imazamox/ – 1.2 l ha-1, Express 50 VG /tribenuron-methyl/ – 50 g ha-1 and their herbicide combinations – Pulsar 40 – 1.2 l ha-1 + Bazagran 480 SL – 1 5 l ha-1, Pulsar 40 – 1.2 l ha-1 + Pendistar 40 SK – 4 l ha-1, Express 50 VG – 50 g ha-1 + Bazagran 480 SL -1.5 l ha-1, Express 50 VG 50 g ha-1 + Pendistar 40 SK – 4 l ha-1 were studied. The herbicides were applied alone and in combinations in the cotton’s growth stage BBCH 51 (First floral buds detectable). The aim was to study the selectivity and the stability of the performances of a group of herbicides and their herbicide combinations on cotton under different weather conditions. It was found that the herbicides Bazagran 480 SL and Pendistar 40 SK have excellent selectivity for the cotton cultivar Viki. The herbicides Pulsar 40 and Express 50 VG and their herbicide combinations with Bazagran 480 SL and Pendistar 40 SK showed higher phytotoxicity on cotton, and the highest phytotoxic effect was observed after the treatments with the herbicide mixtures Pulsar 40 + Pendistar 40 SK and Express 50 VG + Pendistar 40 SK. High yields were obtained after the alone application of the herbicides Pendistar 40 SK and Bazagran 480 SL. The remaining herbicides and herbicide combinations showed higher negative impact on the raw cotton yield. The herbicide mixtures Pulsar 40 + Pendistar 40 SK and Express 50 VG + Pendistar 40 SK had the lowest yields. The herbicides Bazagran 480 SL and Pendistar 40 SK and the herbicide combinations Express 50 VG + Pendistar 40 SK were technologically the most valuable as well. These treatments combined high yield values and high stability of this indicator in the different years.