Selectivity and stability of herbicides, herbicide tank mixtures and herbicide combinations on seed yield of Clearfield oilseed canola (Brassica napus L.)

G. Delchev*

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 31 May 2021; accepted for publication 26 July 2021)

Abstract. During the period 2018-2020 a field experiment was carried out with the winter Clearfield oilseed canola hybrid Phoenix CL (Brassica napus L). Factor A included the years of investigation. Factor B included untreated control, 2 combined herbicides: Cleranda SC and Cleravo SC; 6 herbicide tank mixtures: Electron 500 SC + Maza 4 SL, Springbok + Maza 4 SL, Tanaris + Maza 4 SL, Butisan max + Maza 4 SL, Cliofar 600 SL + Maza 4 SL and Galera super + Maza 4 SL; 6 herbicide combinations: Caliph 480 ЕC + Maza 4 SL, Caliph mega + Maza 4 SL, Bismark CS + Maza 4 SL, Nero ЕC + Maza 4 SL, Brasan 540 EC + Maza 4 SL and Colsor trio ЕC + Maza 4 SL. Herbicides Cleranda, Cleravo and Maza were used in addition with adjuvant Dash HC. Foliar-applied herbicides were treated during 2-4 leaf canola stage. Soil-applied combined herbicides were treated during after sowing before emergence period of the canola. It was found that: (i) the highest seed yields are obtained by use of combined herbicide Cleranda, followed by herbicide tank mixture Electron + Maza and combined herbicide Cleravo; (ii) the high canola yields are also obtained by herbicide tank mixtures Butizan max + Maza, Springbok + Maza, Tanaris + Maza, as well as by herbicide combinations Caliph mega + Maza, Brasan + Maza, Bismarck + Maza; (iii) technologically the most valuable are combined herbicide Cleranda, followed by herbicide tank mixture Electron + Maza and combined herbicide Cleravo; (iv) in terms of technology for growing winter Clearfield oilseed canola, herbicide tank mixtures Springbok + Maza, Butisan max + Maza and Tanaris + Maza, as well as herbicide combinations Caliph mega + Maza, Bismar + Maza and, Nero + Maza get high rating; herbicide tank mixtures Cliofar + Maza and Galera super + Maza and herbicide combinations Caliph + Maza and Colsor trio + Maza get low rating.

Species composition and density of weeds in a grain maize crop depending of soil tillage

P. Yankov*, M. Drumeva

Department of Plant Production, Faculty of Manufacturing Engineering and Technologies,
Technical University of Varna, 1 Studentska Str., 9010 Varna, Bulgaria

(Manuscript received 5 September 2020; accepted for publication 26 October 2020)

Abstract. The study was carried out during 2014-2016 on slightly leached chernozem soil type. The species composition and density of weeds were studied in grain maize grown after previous crop wheat under the following main soil tillage types: ploughing at 24-26 cm, chisel plough at 24-26 cm and no-tillage (direct sowing). The additional tilths of the areas with ploughed and loosened soil included single disking in autumn and double pre-sowing harrowing in spring. A total herbicide was applied for control of the emerging weeds in the variant with direct sowing. The weed control was done according to the standard technology for growing of the crop in this region – treatment with herbicides at stage 3rd-5th leaf of the plants. Weed infestation was read in spring prior to the pre-sowing tillage, immediately before the vegetation treatment with herbicides, and after harvesting. The type of main soil tillage had a statistically significant effect on the species composition and the density of weeds in the grain maize crops grown after previous crop wheat. The use of ploughing, in parallel with the use of chemicals for weed control, decreased the weed infestation in the maize crops. The lower density of weeds under this main soil tillage type was related to changes in the composition and the relative percentage of the respective species in the total infestation. The use of tilths without turning the surface layer and no-tillage in the crop rotation, in spite of the application of herbicides, contributed to the increase of the amount of weeds. The reason for this was the higher variability of weed species typical for shallow tillage types.

Efficacy of different herbicide combinations for weed control in irrigated maize silage

R. Bazitov*

Agricultural Institute, 6000 Stara Zagora, Bulgaria

(Manuscript received 1 October 2019; accepted for publication 13 January 2020)

Abstract: The aim of this study was to establish the efficacy of herbicide combinations between Tender EC and Titus + Magneto SL, and Wing P and Mistral Opti applied in a field of maize under the conditions of mixed irrigation. The study has been carried out with maize cultivated on meadow-cinnamon soil at the experimental field of the Agricultural Institute – Stara Zagora for the period 2014-2016. The research was conducted with a mid-grade hybrid corn LG35.62 with the same background of fertilization and irrigation with the following variants: 1) Control (without herbicides); 2) Wing P – 4000 ml/ha and Mistral Opti – 210 ml/ha, and 3) Tender EC – 1500 ml/ha and a mixture of Titus – 40 g/ha + Magnet SL – 1200 ml/ha. Increasе of maize yield by 41.6% (on average) in comparison with the control variant and by 28.9% compared to the variant Wing P and Mistral Opti was found.

After-effect of foliar-applied herbicides for broad-leaved weeds on the primary germ weight of cotton seeds (Gossypium hirsutum L.)

  1. Barakova, St. Georgiev

 

Field Crops Institute, 6200, Chirpan, Bulgaria

 

(Manuscript received 25 June 2019; accepted for publication 15 August 2019)

 

Abstract. The trial was carried out during 2013-2015, with twelve cotton cultivars (Gossypium hirsutum L.). Influence of herbicides Bazagran 480 SL (bentazone)- 1.5 L/ha, Pulsar 40 (imazamox) – 1.2 L/ha and Express 50 VG (tribenuron-methyl) – 50 g/ha was studied. These herbicides were used during the budding stage of cotton. From the viewpoint of cotton growing technology, technologically the most valuable are cultivars Helius, Trakia, Viki, Filipopolis, Boyana, Avangard, Natalia, Darmi, Dorina and Nelina, in foliar treatment with herbicide Bazagran 480 SL. Technologically the most valuable are cultivars Chirpan-539, Helius, Viki, Boyana and Natalia in foliar treatment with herbicide Pulsar 40. Technologically the most valuable are cultivars Helius, Trakia, Viki and Nelina in foliar treatment with herbicide Express 50 VG. These variants combine high primary germ weight and high stability of this index during the different years.

Weeds and weed control in forage pea: A Review

  1. Ivanov

Agricultural University, 4000 Plovdiv, Bulgaria

(Manuscript received 12 February 2018; accepted for publication 15 April 2019)

Abstract. A major limitation factor for the low productivity in peas is weeding. A particularly critical moment in the race between the crop and weeds is the early period of growth and development. Given the influence of the varying climatic and soil conditions on the diversity and density of weed species, a differentiated approach is needed to remove them by using chemical and agrotechnical means. Studies on the varietal susceptibility to herbicides in forage pea in Bulgaria are very limited due to the fact that varietal diversity was not available in the recent past. The objective of the paper is to present a short analysis of the studies relating to weeding in peas and the control of the more important weed groups in it as well as to establish an individual approach in applying agrotechnical and chemical methods for weed control in growing different pea varieties of winter and spring forms. The use of pea varieties different in biological type as well as the possibilities to use varieties from the European variety list in modern agriculture determines the need to test the reaction of each individual variety not only to the herbicides recommended for this crop, but also to new herbicidal preparations and doses. Determining the composition of weed associations, applying suitable herbicides and herbicide mixtures in weed control of pea, combined with proper agrotechnics, is a prerequisite for optimizing the biological productive potential of the crop.

 

Productivity and yield stability at late treatment of durum wheat (Triticum durum Desf.) with antibroadleaved herbicides.

Gr. Delchev*, S. Angelova

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 5 July 2018; accepted for publication 1 February 2019)

Abstract. The aim of the study was to investigate the productivity and yield stability at durum wheat (Triticum durum Desf.) treated with antibroadleaved herbicides during 3-rd stem node stage. The experiment was conducted during 2012-2014 on pellic vertisol soil type. Under investigation was Bulgarian durum wheat cultivar Victoria (Triticum durum var. valenciae). A total of 20 antibroadleaved herbicides were tested: Granstar 75 DF, Granstar super 50 SG, Ally max SG, Arat, Biathlon 4 D, Derby super WG, Mustang 306.25 SC, Weedmaster 646 CL, Sunsac, Secator OD, Logran 60 WG, Lintur 70 WG, Akurat 60 WG, Akurat extra WG, Eagle 75 DF, Herbaflex, Starane 250 EK, Sanafen, Dicotex 400 and Herby 675. All herbicides were treated in 3-rd stem node stage of durum wheat. It was found that during 3-rd stem node stage of durum wheat the antibroadleaved herbicides Arat, Biathlon, Derby super, Secator, Lintur, Akurat, Akurat extra and Starane can be used. These herbicides do not have a negative influence on grain yield. The most unstable yield is obtained after the treatment with herbicides Granstar, Granstar super, Ally max, Sunsac, Logran, Eagle, Herbaflex and Herby. Their selectivity to durum wheat is influenced most strongly by weather conditions during the vegetation period. From the viewpoint of technology for durum wheat growing, during 3-rd stem node stage technologically the most valuable are herbicides Derby super, Arat, Biathlon, Secator, Akurat, Akurat extra and Lintur. After the treatment with them high grain yield with high stability with relation to different years is obtained. The herbicides Granstar, Granstar super, Ally max, Sunsac, Weedmaster, Logran, Eagle, Herbaflex, Sanafen, Dicotex and Herby cannot be used during 3-rd stem node stage of durum wheat.

Productivity and yield stability at late treatment of durum wheat (Triticum durum Desf.) with antibroadleaved herbicides II. Influence at treatment during 2-nd stem node stage

Gr. Delchev*, M. Delcheva

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 17 May 2018; accepted for publication 16 October 2018)

Abstract. Theresearchwasconductedduring2012-2014onpellicvertisolsoiltype.InvestigatedwastheBulgariandurumwheatcultivarVictoria(Triticum durum var. valenciae). A total of 20 antibroadleaved herbicides were investigated: Granstar 75 DF, Granstar super 50 SG, Ally max SG, Arat, Biathlon 4 D, Derby super WG, Mustang 306.25 SC, Weedmaster 646 CL, Sunsac, Secator OD, Logran 60 WG, Lintur 70 WG, Akurat 60 WG, Akurat extra WG, Eagle 75 DF, Herbaflex, Starane 250 EK, Sanafen, Dicotex 400 and Herby 675. All herbicides were treated in 2-nd stem node stage of durum wheat. During 2-nd stem node stage of durum wheat the following antibroadleaved herbicides can be used: Arat, Biathlon, Derby super, Mustang, Secator, Lintur, Akurat, Akurat extra, Starane, Dicotex and Herby. These herbicides do not have a negative influence on grain yield. The most unstable treatments are with herbicides Granstar, Granstar super, Ally max, Sunsac, Logran, Eagle, Herbaflex and Herby. Their selectivity to durum wheat is influenced most strongly by weather conditions during the vegetation period. From the viewpoint of technology for durum wheat growing, during 2-nd stem node stage technologically the most valuable are the herbicides Derby super, Arat, Biathlon, Secator, Akurat, Akurat extra and Lintur. Their application provides high and stable grain yield during different years. The herbicides Granstar, Granstar super, Ally max, Sunsac, Weedmaster, Logran, Eagle and Herbaflex cannot be used during 2-nd stem node stage of durum wheat.

Application of herbicides on common winter wheat (Triticum aestivum L.) at different doses and their reflection on the structural elements of spike

  1. Z. Petrova, Nankova

 

Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria

 

DOI: 10.15547/ast.2018.03.046

(Manuscript received 13 June 2018; accepted for publication 25 July 2018)

 

Abstract. The aim of this investigation was to determine the effect of the application dose of herbicides on structural elements of spike in common winter wheat (Triticum aestivum L.). The investigations were carried out during 2015–2017 at Dobrudzha Agricultural Institute (DAI) – town of General Toshevo. The following herbicides were used: Derby super WG (33 g/ha; 66 g/ha; 132 g/ha), Secator ОD (100 mL/ha; 200 mL/ha; 400 mL/ha), Ergon WG (50 g/ha; 100 g/ha; 200 g/ha), Granstar super 50SG (40 g/ha; 80 g/ha; 160 g/ha), Lintur 70WG (150 g/ha; 300 g/ha; 600 g/ha) and Mustang 306.25 СК (800 mL/ha; 1600 mL/ha; 3200 mL/ha) from the group of sulfunylureas with various mechanism of action. The preparations were applied at three doses – optimal, double and quadruple, at stage 29 of common winter wheat cultivar Dragana, Zlatitsa and Kalina. The herbicide effect was determined by the quantitative weight method and evaluated by the EWRS scale. These were the traced structural elements of the wheat spike: length of spike (cm), number of spikelets per spike, number of grains per spike, weight of grain per spike (g) and weight of 1000 grains (g). Four-factor dispersion analysis was applied. The factors year conditions, cultivar, herbicide and dose were traced. The factors with the highest strength of effect were the year conditions (10-95%) and the used cultivar (2-87%). Significantly lower was the effect of the factors applied herbicide (2-4%) and dose (1-2%) on the investigated structural elements of spike.

 

Productivity and yield stability at late treatment of durum wheat (Triticum durum Desf.) with antibroadleaved herbicides. I. Influence at treatment during 1-st stem node stage

Gr. Delchev, D. Delchev

 

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

 

DOI: 10.15547/ast.2018.03.043

(Manuscript received 25 May 2018; accepted for publication 20 July 2018)

 

Abstract. The research was conducted during 2012 – 2014 on pellic vertisol soil type. Under investigation was Bulgarian durum wheat cultivar Victoria (Triticum durum var. valenciae). A total of 20 antibroadleaved herbicides were investigated: Granstar 75 DF, Granstar super 50 SG, Ally max SG, Arat, Biathlon 4 D, Derby super WG, Mustang 306.25 SC, Weedmaster 646 CL, Sunsac, Secator OD, Logran 60 WG, Lintur 70 WG, Akurat 60 WG, Akurat extra WG, Eagle 75 DF, Herbaflex, Starane 250 EK, Sanafen, Dicotex 400 and Herby 675. All herbicides were treated in 1-st stem node stage of durum wheat. During 1-st stem node stage of durum wheat the antibroadleaved herbicides Arat, Biathlon, Derby super, Mustang, Weedmaster, Secator, Lintur, Akurat, Akurat extra, Eagle, Starane, Sanafen, Dicotex and Herby can be used. These herbicides do not have a negative influence on grain yield. The most unstable are herbicides Granstar, Granstar super, Ally max, Sunsac, Logran, Herbaflex and Herby. Their selectivity to durum wheat is influenced most strongly by weather conditions during the vegetation period. From the viewpoint of technology for durum wheat growing, during 1-st stem node stage technologically the most valuable are herbicide Derby super, Arat, Biathlon, Secator, Akurat, Akurat extra and Lintur. They combine high grain yield with high stability in relation to different years. The herbicides Granstar, Granstar super, Ally max, Sunsac, Logran and Herbaflex cannot be used during 1-st stem node stage of durum wheat.

 

Achievements and problems in the weed control in grain maize (Zea mays L.)

  1. G. Delchev, M. Georgiev

Department of Plant Production, Faculty of agriculture, 6000 Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 28 November 2016; accepted for publication 5 February 2018)

Abstract. Chemical control has emerged as the most efficient method of weed control. Herbicides combinations and tank mixtures of herbicides with adjuvants, fertilizers, growth regulators, fungicides, insecticides, are more effective than when they are applied alone in maize crops. Their combined use often leads to high synergistic effect on yield. There are maize hybrids resistant to imidazolinone for Clearfield technology, but they have not yet been introduced in Bulgaria. Data regarding herbicide for chemical control of perennial graminaceous weeds in maize crops are quite scarce even worldwide. The problem is the persistence of some herbicides used in the predecessors on succeeding crops, which is directly related to the weather conditions during their degradation. Most of the information in maize relates to conventional technology for weed control. There is not information about the new Duo system technology in grain maize and the hybrids used are resistant to cycloxydim. A serious problem is also the volunteers of the Clearfield and Express sun sunflower. They have resistance to herbicides different from that of conventional sunflower hybrids. There is no information yet in scientific literature about control of these volunteers.