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The use of herbicides is а traditional method for weed control in crop-producing systems. Along with the high effective weed control, herbicides might cause phytotoxicity for crop plants, due to insufficient herbicide selectivity, combining herbicide treatment with unsuitable meteorological conditions, long-term persistence of herbicide in the soil or off-target transfer of the herbicide – drift. Imazamox is a selective herbicide of imidazolinone group, used to control annual and perennial weeds in imidazolinone-resistant (IMI-R) crops. Protein hydrolysates (PHs) are a group of plant biostimulants containing small peptides and free amino acids, reported to ameliorate plant abiotic stress tolerance, including herbicide phytotoxicity. This report evaluates the damaging effect of simulated imazamox drift on growth, photosynthetic performance and productivity of maize plants as well as the efficiency of foliar application by protein hydrolysates as therapy means. The received results demonstrated that the simulated imazamox herbicide drift has a strong inhibiting effect on maize plants. This is well illustrated by the retarded growth of maize plants, their disrupted photosynthetic activity and productivity losses. The foliar supply of PHs to imazamox damaged maize plants ameliorates their photosynthetic performance, growth and crop productivity., Използването на хербициди е традиционен метод за контрол на плевелната растителност при полски култури. Наред с високоефективния контрол на плевелите, хербицидите могат да причинят фитотоксичност при културните растения поради недостатъчна селективност, третиране при неподходящи метеорологични условия, остатъчни количества в почвата или при отлитане хербицида извън целевата култура – хербициден дрифт. Имазамоксът е селективен хербицид от групата на имидазолиноните, прилаган за контрол на едногодишни и многогодишни плевели в комбинация с устойчиви хибриди (IMI-R). Протеиновите хидролизати (PHs) са група растителни биостимуланти, съдържащи малки пептиди и/или свободни аминокиселини, за които е известно, че подобряват толерантността на растенията към абиотичен стрес, включително хербицидна фитотоксичност. Настоящото проучване има за цел да установи ефекта на симулиран дрифт на хербицида имазамокс върху растежа, фотосинтетичната активност и продуктивността на царевични растения, както и да оцени ефективността на листното приложени биостимуланти от групата на протеиновите хидролизати като терапевтично средство. Получените резултати показват, че симулираният хербициден дрифт оказва силен инхибиращ ефект върху царевичните растения. Това се вижда ясно от потиснатия растеж на царевичните растения, нарушената им фотосинтетичната активност и загубата на продуктивност. Листното прилагане на протеинови хидролизати върху увредените от имазамокс царевични растения подобрява фотосинтетичната им активност, растежа и продуктивността на културата.

During the vegetation season of 2017-2018 a field trail with the winter wheat variety "Enola" was conducted. The study was stated on the experimental field of the base for training and implementation of the Agricultural University of Plovdiv, Bulgaria. Variants of the trial were: 1. Untreated control; 2. Quelex® (halauxifen-methyl + florasulam) – 3,75 g/da; 3. Quelex® - 5 g/da; 4. Quelex® - 3,75 g/da + Dasoil (adjuvant) – 100 ml/da; 5. Quelex® 5 g/da + Dasoil – 100 ml/da; 6. Derby® Super (aminopyralid-potassium + florasulam) – 2,5 g/da; 7. Derby® Super – 3,3 g/da; 8. Derby® Super – 2,5 g/da + Dasoil – 100 ml/da; 9. Derby® Super – 3,3 g/da + Dasoil – 100 ml/da; 10. Starane® Gold (florasulam + fluroxypyr) 120 ml/da; 11. Starane® Gold – 150 ml/da; 12. Starane® Gold – 180 ml/da; 13. Biathlon® 4 D (tritosulfuron + florasulam) – 5 g/da; 14. Sekator® OD (amidosulfuron + iodosulfuron) – 10 ml/da; 15. Mustang® SC (2,4 D ester + florasulam) – 60 ml/da. The efficacy of the studied herbicide products by the 10 score scale of EWRS was recorded. The results were compared with untreated control. The herbicide selectivity for the winter wheat by the 9 score scale for phytotoxicity of EWRS was reported. The highest herbicide efficacy (95 – 100%) against the existing weeds and the highest yield (702,21 kg/da) was obtained at the variant treated with Mustang® SC. The aim of the study is to determine the efficacy of herbicides for control of broadleaf weeds in winter wheat.

The experiment was carried out during 2016 – 2019 on the agricultural lands of the town of Kubrat, Bulgaria. The aim of the study was to establish the effect of some herbicides and herbicide combinations on weed density, as well as on the productivity and yield of winter wheat (Avenue cultivar). The experiment included 8 treatments: 1. Control - untreated; 2. Control (economic) - untreated, weed free; 3. Trimur (750 g/kg tribenuron-methyl) – 0.020 kg ha-1; 4. Sekator (25 g/l jodosulfuron + 100 g/l amidosulfuron) – 1.00 l ha-1; 5. Puma Super (69 g/l fenoksaprop-P-ethyl) - 1.00 l ha-1; 6. Axial (50 g/l pinoxaden) – 0.90 l ha-1; 7. Sekator - 1.00 l ha-1 + Puma Super – 1.00 ml ha-1; 8. Trimur – 0.020 kg ha-1 + Puma Super – 1.0 l ha-1. All studied herbicides showed good control against the weeds and reduced their density. The structural elements of the yield after the herbicide application, except for the herbicide combination Trimur + Puma Super were higher than those of the untreated control. The herbicide combination Sekator + Puma Super controlled 90.0% of the broadleaf and 100% of the grass weeds and the highest grain yield of 6.550 t ha-1 average for the period was obtained. It is recommendable to use this herbicide mixture in wheat fields with mixed weed infestation. The lowest yield was obtained after the application of Trimur + Puma Super. This was probably due to phytotoxic damage caused by the incompatibility of these two herbicides

In this presentation, the outcomes of a specific EWRS regional meeting organized by the Working Group »Optimization of Herbicide Use in an IWM context« are documented. Data were obtained by a questionnaire survey and a face-to-face group discussion. The idiosyncratic structure and systemic nature of IWM systems, as compared with other IPM systems, draws on many strategies with a combination and integration of single weed management tactics at temporal and spatial scale. The questionnaire included queries with multiple-choice predefined answers and left space for open answers. All those were given a significance score value (1 to 5). During the meeting, the face-to-face group discussion was aimed on the fine elaboration, sorting and ranking of the major weed problems and obstacles for IWM systems implementation in South East European countries. Regional South East countries address the IWM by different approaches based on their status towards EU. Countries outside the EU, have set up voluntary public and private entities to promote IWM whereas Member States of the EU have implemented the Sustainable Use Directive (Dir. 2009/128/EC) aiming to regulate use of pesticides (herbicides, in particular), and are required to set up National Plans. Regional cropping systems frequently face similar (more or less) major weed problems and IWM challenges, research needs and priorities and extension services upgrades to tackle IWM implementation. Identifying the current obstacles and propose measures to eliminate them would boost national efforts as they could benefit from a common IWM framework and transnationally approaches.

Three block design field experiments were carried out in the period 2012 – 2015, following the same methods, on three different sites in the country, which differ significantly in the spectrum of the available weeds. The subject of the experiments was the improved version of the Clearfield Plus technology. In all the three years the sunflower hybrid ES Candimis CL Plus was planted on the three sites. The major aim of the experiments on the three sites was to establish the selectivity for sunflower and the efficacy of Pulsar 40 (40 g/l imazamox) against almost all the economically important weeds in that crop. The reported phytotoxicity caused to sunflower on the three sites in the three years was expressed in a slight discoloration of the treated sunflower plants, which was totally overcome between the 14th and 20th day. The results of the experiments show that the greatest differences in the efficacy of Pulsar 40 were reported about its activity against perennial weed species. When Pulsar 40 was applied separately without DASH, its efficacy against Johnson grass, corn thistle, field bindweed, hemp agrimony, rough cocklebur, white goosefoot, purslane and broomrape was significantly reduced. Referring to its efficacy against the annual broad-leaved weed species redroot pigweed, charlock mustard, wild radish, clea-vers, black nightshade, etc., it was 100% and no differences were observed between the rates of 80, 100 and 125 ml/da. The separate use of the herbicide at a rate of 125 ml/da shows the same efficacy against more stubborn weeds, as that of Pulsar applied at the rate of 80 ml/da together with 80 ml/da of the adjuvant DASH.

A field trial on chemical control of rat’s tail fescue (Festuca myuros) in rapeseed fields was carried out in the period 2012-2014. The following herbicides registered for application in rapeseed, were used in the experiment: Butisan 400 SC (metazachlor – 400 g/l), Butisan Max (metazachlor – 200 g/l + dimethenamid-P – 200 g/l + quinmerac – 100 g/l), Stratus ultra (100 g/l cycloxydim + tensid), Agil (100 g/l propaquizafop + surfactant), Fusilade forte (150 g/l fluazifop-P-butyl) and Cleranda (17,5 g/l imazamox + 375 g/l metazachlor). It was established that very good results were achieved in the control of rat’s tail fescue after timely treatment with the herbicide chemical Butisan 400 SC. Another reliable alternative for control of that weed species was the application of the herbicide Cleranda at the rate of 150-200 ml/dka, when using Clearfield technology. The results of the trial showed that three of the registered herbicides against grassy weeds in rapeseed – Stratus ultra, Fusilade Forte and Agil, did not display any herbicide efficacy against rat’s tail fescue, regardless of treatment rate and time of application. The only vegetation herbicide showing very good results is Cleranda. The results of the present study show that treatment applied at the stage of 4th–6th leaf has a slightly better effect compared to the variants with earlier (2nd–4th leaf) and later (6th–8th leaf) treatments. The earlier treatment is more risky for secondary weed infestation, the level of which can be lower or higher in the different years. The delayed treatment, especially if carried out in spring, reduces the herbicide effect of the active substance imazamox against grassy weeds, including rat’s tail fescue.