Selectivity and stability of vegetation-applied herbicides in cotton (Gossypium hirsutum L.)

T. Barakova1*, G. Delchev2

1Field Crops Institute, 6200 Chirpan, Bulgaria
2Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 16 May 2016; accepted for publication 26 May 2016)

Abstract. An experiment was carried out during 2013 – 2015 in the experimental field of the Field Crops Institute, Chirpan, with two cotton cultivars − Helius and Darmi (Gossypium hirsutum L.). Herbicides: Goal 2 E, oxyfluorfen (80 ml/da); Linuron 45 SC, linuron (200 ml/da); Wing-P, pendimethalin + dimethenamid (400 ml/da); Merlin 750 WG, isoxaflutol (5 g/da); Bazagran 480 SL, bentazone (150 ml/da) were investigated. They were treated separately or combined with growth regulator Amalgerol (500 ml/da) or foliar fertilizer Lactofol O (500 ml/da) in the budding stage of the cotton. It was established that selectivity is the lowest in the two cotton cultivars with herbicides Linuron 45 CK and Merlin 750 WG. The purpose of this investigation was to establish the selectivity and stability of some herbicides and their tank mixtures on the cotton by influence of different meteorological conditions. It has been found that the highest phytotoxicity on cotton is given the vegetation-applied herbicides Merlin and Linuron. Foliar fertilizer Laktofol O reduces phytotoxicity of herbicides Goal, Wing, Merlin and Bazagran in two cotton cultivars. Herbicides Wing and Bazagran have excellent selectivity for the two cotton cultivars – Helius and Darmi. The highest yield was obtained by vegetation treatment with herbicide Bazagran, followed by herbicides Wing and Goal. Tank mixtures of Goal, Bazagran and Wing with Laktofol, followed by those with Amalgerol are technologically the most valuable. They combine high yield with high stability over the years. Аlone application of herbicides Linuron and Merlin and their tank mixtures with Amalgerol and Laktofol have low estimate.