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.

Effect of the herbicide treatment dose on the weed infestation in common winter wheat

Z. Petrova*

Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria
(Manuscript received 10 June 2017; accepted for publication 24 October 2017)

Abstract. The aim of this investigation was to determine the effect of the treatment dose of herbicides on the weed infestation in common winter wheat. The investigations were carried out during 2015 –2016 at Dobrudzha Agricultural Institute (DAI) – 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 (according to Zadoks et al., 1974) of common winter wheat cultivars Dragana, Zlatitsa and Kalina. The herbicide effect was determined by the quantitative weight method and evaluated by the EWRS scale. Regardless of the used dose and the cultivar, Derby super WG, Secator OD, Lintur 70WG and Mustang 306.25СК had highest efficiency (100%) against the following investigated weeds: Sinapis arvensis L., Matricaria chamomilla L., Anthemis arvensis L., Galium tricorne (Stock.), Consolida orientalis (J. Gay) and Cirsium arvensis L. Ergon WG and Granstar super 50SG had 100% efficiency against Sinapis arvensis L., Matricaria chamomilla L. and Anthemis arvensis L. and lower effect (90-94%) on Galium tricorne (Stock), Consolida orientalis (J. Gay) and Cirsium arvensis L.

Achievements and problems in the weed control in grain sorghum (Sorghum Bicolor Moench.)

Gr. Delchev*, M. Georgiev

1Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 28 November 2016; accepted for publication 21 March 2017)

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 applied alone on sorghum crops. Their combined use often leads to high synergistic effect on yield. The use of herbicide antidotes for the treatment of seeds in sorghum is a safe way to overcome its high sensitivity to many herbicides. Data regarding herbicide for chemical control of annual graminaceous weeds in sorghum crops are quite scarce even worldwide. 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 on sorghum relates to the conventional technology for weed control. There is no information about the new Concep technology in grain sorghum. 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 on control of these volunteers.

Problems and achievements of cotton (Gossypium Hirsutum L.) weeds control

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 2 June 2017; accepted for publication 17 August 2017) Abstract. Weed control in the cultivation of cotton is critical to the yield and quality of production. The influence of economically important weeds was studied. Chemical control is the most effective method of weed control in cotton but much of the information on it relates to primary weed infestation. Problems with primary weed infestation in cotton have been solved to a significant extent. The question of secondary weed infestation with annual and perennial graminaceous weeds during the period of cotton vegetation is also determined largely by the use of antigraminaceous herbicides. The data related to herbicides to effectively control secondary germinated broadleaf weeds in conventional technology for cotton growing are quite scarce, even globally. We are still seeking effective herbicides for control of these weeds in cotton crops. Studies on their influence on the sowing characteristics of cotton seed and the quality of cotton fiber are still insufficient. In the scientific literature there is not enough information on these questions. The combinations of herbicides, as well as their tank mixtures with fertilizers or plant growth regulators are more efficient than autonomous application. Often during their combined application higher synergistic effect on yield is produced. There is information about cotton cultivars resistant to glyphosate. These cultivars are GMO and they are banned within the European Union, including Bulgaria.