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.

 

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.

Phytosanitary conditions of the organic field and boundary

D. Atanasova1*, V. Maneva1, N. Grozeva2

1Institute of Agriculture, Karnobat, Bulgaria
2Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 1 July 2016; accepted for publication 11 August 2016)

Abstract. In the field and boundary of certificated field for organic farming in the Institute of Agriculture – Karnobat have been observed and described diseases, pests and weeds in wild and cultivated plants and dependencies between them are reported. The cultural plant diversity at the certified field for organic farming is significant and amounts to 32 species and varieties of cereals. The weeds in crops and in the free areas significantly differed. In crops, the annual broadleaf weeds had greater diversity of species (Anthemis arvensis L., Lathyrus aphaca L., Papaver phoeas L., Polygonum aviculare L., Polygonum convolvulus L.) and at the boundaries – the cereal weeds (Аpera spica-venti L., Hordeum murinum L., Bromus tectorum L., Poa pratensis L.). At the adjacent areas the perennial broadleaf weeds – Cirsium arvense (L.) Scop. and Convolvulus arvensis L. were not found. At the boundaries less pest species and types of diseases were registered than in the crop fields. In cereals the most common pests are Sitobion avenae L., Aelia acuminate L., Eurygaster austriaca Schr. Beneficial insects are Coccinella septempunctata L. The most common diseases are Erysiphe graminis and Rhynchosporium secalis (Oudem.) Davis.

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Effect of some soil herbicides on vegetative habits of almond trees of ‘Nonpareil’ cultivar grown in a second-year nursery field

Z. Rankova1*, M. Tityanov2

1Fruit Growing Institute, 4004 Plovdiv, 12 Ostromila, Bulgaria 2University of Forestry, 10 Kliment Ohridski, 1756 Sofia, Bulgaria

(Manuscript received 31 May 2016; accepted for publication 26 July 2016)

Abstract. The study was carried out in the period 2010 – 2012 in a nursery field established on the territory of the Fruit-Growing Institute, Plovdiv. The effect of the combined soil-applied herbicide metolachlor + oxyfluorfen (Metofen) and the contact soil herbicide with foliar activity flumioxazine (Pledge 50 WP) on the vegetative habits of ‘Nonpareil’ almond cultivar grafted on almond seedling rootstock was evaluated. In the period 15-25 March, before beginning of vegetation, soil herbicides were applied in the row strip in the second-year nursery field. The following variants were included in the study: 1. Control (untreated, hand- weeded); 2. Metofen – 120 ml/da; 3. Metofen – 240 ml/da; 4. Pledge 50 WP – 8.0 g/da; 5. Pledge 50 WP – 20.0 g/da. The effect of the herbicides on weed infestation and on the vegetative habits of the cultivar/rootstock combination ‘Nonpareil’/almond seedling rootstock was followed up. The results showed that the herbicides applied at the tested rates had a good control on weed infestation and the herbicide activity continued for 3.5-4 months. That makes it possible to eliminate the competitive impact of weeds on the development of the grafted trees for 4-5 months after beginning of vegetation. Visual symptoms of phytotoxicity (chlorosis or necrosis in the leaves and shoots) or an obvious suppression of the development of the grafted trees in the treated variants were not established. A depressing effect on growth of the grafted trees was reported after treatment with Metofen. The contact herbicide with soil and foliar activity Pledge 50 WP – 8.0 g/da can be applied for weed control in a second-year nursery field of almond trees grafted on bitter almond seedling rootstock.

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Influence of foliar herbicides treatment on malting barley (Hordeum vulgare L.) productivity of Emon, Vanessa and Vicky varieties

D. Atanasova*, V. Maneva

Institute of Agriculture, 8400 Karnobat, Bulgaria
(Manuscript received 1 July 2016; accepted for publication 26 August 2016)

Abstract. During the period 2012 – 2014 in the Institute of Agriculture, Karnobat a field experiment was conducted with winter malting barley varieties Emon, Vanessa and Vicky. The influence of broadleaf (dicotyledonous) herbicides alone and in their combination with wild oat (monocotyledonous) in tillering stage of the crop was studied in optimal and double doses. The herbicide selectiveness was assessed according to the EWRS scale. Yields were reported after harvest. In variety Vanessa during the treatment with Derby Super, Granstar Super, Sekator OD and combination of Puma Super 7.5 EW + Sekator OD in optimal doses, the yield does not differ from the weed control. Variety Vicky endures well the treatment with optimal doses in all of the tested herbicides, except Husar Max. In treatment with double doses, only Granstar Super does not affect negatively the yield of grain. Comparing the data from ANOVA about the role of herbicides and year conditions on the malting barley varieties it can be concluded that the yield of variety Emon is the most stable in regard to herbicides applied in optimal doses (5%), followed by Vanessa (17%) and Vicky (18%). At application of the herbicides in double doses, their influence is increased – in variety Emon up to 15%, and in varieties Vanessa and Vicky – up to 23%.

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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.

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Changes in the leaf gas exchange of common winter wheat depending on the date of application of a set of herbicides

Z. Petrova1*, Z. Zlatev2

1Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria
2Department of Plant Physiology, Faculty of Agronomy, Agricultural University, 12 Mendeleev, 4000 Plovdiv, Bulgaria

Abstract. The aim of this investigation was to determine the effect of the date of application of a set of herbicides on the foliar gas exchange of common winter wheat. The investigations were carried out in 2013 and 2014 at Dobrudzha Agricultural Institute (DAI). The following herbicides were used: Derby super VG (33 g/ha), Granstar 75DF (15 g/ha), Lintur 70VG (150 g/ha), Secator ОD (100 ml/ha), Mustang 306.25 СК (800 ml/ha), Palace 75WG+oil (250+1000 g/ml/ha) and Husar Мax ОD (1000 ml/ha) from the group of suflonylureas with various mechanism of action. The preparations were applied at two stages of common winter wheat cultivars Aglika and Enola (stages 29 and 32 according to Zadoks). The indices of leaf gas exchange were followed: rate of net photosynthesis (А), intensity of transpiration (E), stomatal conductivity (gs) and intercellular concentration of СО2 (ci). It was found that the later application (stage 32) of Lintur 70VG and Mustang 306.25СК caused visible signs of phytotoxicity. These were expressed as anthocyanin pigmentation of leaves and spikes and as partial to full sterility of spikes, stronger after using Lintur VG and weaker after Mustang 306.25СК. Following a delayed application of the herbicides, slower rate of growth of plants was observed, as well as disturbances in the parameters of foliar gas exchange. The high rate of A at comparatively low E and gs and the low ci in the weeded check indicated that the plants spent considerable energy resources to overcome the negative effect of weeding.

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Efficacy and selectivity of herbicides and herbicide combinations at winter oilseed canola, grown by conventional and Clearfield technologies

Gr. Delchev*
Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. During the period 2010 – 2012, on the experimental field of the Field Crops Institute, Chirpan a field experiment was carried out with imitolerant hybrid winter oilseed canola PT200CL (Brassica napus L.). A total of 16 variants were investigated. They include antigraminaceous herbicides, antibroadleaved herbicides and plant growth regulators. Herbicide Cleranda by Clearfield technology has very good efficacy against all graminaceous and broadleaved weeds and volunteers, including Sinapis arvensis and Raphanus raphanistrum and volunteers of Coriandrum sativum. Herbicides Salsa and Modown have very good efficacy against all broadleaved weeds, including against cruciferous weeds Sinapis arvensis and Raphanus raphanistrum and volunteers of Coriandrum sativum. They must be combined with antigraminaceous herbicide by mixed weeding with graminaceous and broadleaved weeds. Vegetation-applied herbicide Runway has no efficacy against Sinapis arvensis and Raphanus raphanistrum and poorer efficacy against volunteers of Coriandrum sativum. Autumn treatment by herbicide Modown causes poor phytotoxicity in canola. Spring treatment with Modown leads to a high and more difficult to overcome phytotoxicity. The highest seed yields are obtained by the variants Cleranda + Caramba and Salsa + Pantera + Folicur, followed by variants Modown + Agil + Orius and Runway + Pantera + Folicur.

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Effect of the date of application of a set of herbicides in common winter wheat crops on weed infestation

Z. Petrova*, G. Sabev

1Department of Agrotechnology, Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria

Abstract. The aim of this investigation was to determine the effect of the date of introduction of herbicides on the infestation with weeds. The experiments were carried out during 2012 – 2013 at Dobrudzha Agricultural Institute (DAI). The following herbicides were used: Derby super VG (33 g/ha), Palace 75WG + oil (250 + 1000 g/ml/ha), Granstar 75DF (15 g/ha), Lintur 70VG (150 g/ha), Husar Max OD (1000 ml/ha), Secator OD (100 ml/ha), Mustang 306, 25 CK (800 ml/ha) from the group of sulphonylureas with various modes of activity. The preparations were introduced at three phenophases of winter common wheat cultivar Aglika (29, 32 and 37 according to the scale of Zadoks). The herbicide effect was determined by a quantitative weight method and evaluated by the EWRS scale. The results from the obtained data showed that Derby super VG, Luntur 70VG, Secator OD and Mustang 306, 25 CK had the highest effect when introduced at phenophases 29 of wheat growth (the efficiency varied from 95 % to 100 %). With the later dates of herbicide application and the later growth stages of weeds, a tendency towards lower efficiency was observed.

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Efficacy and selectivity of vegetation-applied herbicides and their mixtures with growth stimulator Amalgerol premium at oil-bearing sunflower grown by conventional, Clearfield and ExpressSun technologies

G. Delchev
Abstract. During the period 2010 – 2012, on the experimental field of the Field Crops Institute – Chirpan was carried out a field experiment with oil-bearing sunflower (Helianthus annuus). A total of 18 variants from the three technologies for oil-bearing sunflower growing were investigated – conventional (hybrid Arena), Clearfield (hybrid Alego) and ExpressSun (hybrid P64LE20). Vegetation-applied herbicides Goal, Raft and Pledge combined with the soil-applied herbicide Pelican provide good control of annual broadleaved weeds in conventional technology for sunflower growing. Combinations of herbicides Stomp, Wing with herbicide Pelican can be applied to mixed weeding from annual grassy and some broadleaved weeds, but with the absence of Xanthium strumarium, Cirsium arvense and Convolvulus arvensis. Herbicide combination Modown + Pelican should be used in secondary weeding primarily from annual broadleaved weeds, but with the absence of Xanthium strumarium. Herbicide tank mixtures Pulsar + Stomp by Clearfield technology and Express + Stratos ultra by ExpressSun technology completely destroyed all annual and perennial grassy and broadleaved weeds. Vegetation use of herbicides by conventional technology causes high phytotoxicity on sunflower. Phytotoxicity was the highest by herbicide Goal, followed by Pledge. Phytotoxicity is weaker by herbicides Stomp, Raft, Wing and Modown. Treatment of growth stimulator Amalgerol premium with herbicides Goal, Raft, Wing, Pledge and Modown as tank mixtures increases the selectivity of these herbicides.
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