Search

Particle drift happens during herbicide application when droplets travel outside the intended site. Different nozzles produce various range of droplets, so they play a very important role in coverage and drift occasions. When nozzles produce small droplets, the potential for off-target movement is very high. Another important factor determining particle drift is the distance between crops. Wind velocity gives the energy to herbicide particles to move away from the target place. Therefore, a drift simulation of herbicide (mesotrione and rimsulfuron plus thifensulfuron-methyl mixture) was done in a wind tunnel, using different nozzles Extended Range (XR) and Turbo TeeJet Induction (TTI). The wind speed was set at 4.4 m/s, representing the least favourable conditions where applications are possible. In the wind tunnel, eight crops (cantaloupe, cotton, green bean, pumpkin, soybean, sunflower, wheat, and watermelon) were positioned at 4, 6, 9, and 12 m downwind distances from the nozzle, and drift was simulated. Following treatments, plants were returned to a greenhouse for 28 days, and biomass reduction was recorded. Artificial collectors (Mylar cards) and water sensitive cards were positioned alongside plants. According to obtained results, spraying with XR nozzle influences higher injuries than TTI nozzle. Tracer deposition was higher at all distances when XR nozzle was used. Accordingly, droplet numbers, covered area, Volume Median Diameter (VMD), and deposition were higher on water sensitive cards when spraying were done using XR nozzle. As a consequence, higher biomass reduction occurred using the XR nozzle. The most sensitive crops were cantaloupe, pumpkin and sunflower, while the most tolerant were soybean and wheat. [ABSTRACT FROM AUTHOR]

Potential for off-target movements follows every herbicide application. Because the launch of acetolactate synthase (ALS)- and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-tolerant crops will increase the treated area, there is a need to assess the possible negative consequences of any particle drift from those herbicides. Drift happens with every pesticide application, requiring mitigation. Various factors influence drift. Some, such as nozzle type, working pressure, and boom height, can be managed. Others, such as wind, are not easy to manage. In our study, an herbicide tank mixture of mesotrione with rimsulfuron plus thifensulfuron-methyl was sprayed in a low-speed wind tunnel to simulate drift. The airspeed was set at 4.4 m s−1, representing the labeled upper limit for applications. The herbicide solution was sprayed through XR110015 and TTI110015 nozzles. Eight crops were exposed to herbicide drift treatments and biomass data were collected. Droplet size spectra and tracer depositions were evaluated. Tracer deposition was on average threefold higher in all downwind distances (0.5, 1, 2, 3, 4, 6, 9, and 12 m) from the XR nozzle in comparison to the TTI nozzle. As a consequence, greater biomass reduction was recorded for applications with the XR compared to the TTI nozzle from 1 to 12 m downwind. At 12-m distance, biomass was decreased by 7–78% using XR nozzle while 1–27% using the TTI nozzle. Because drift can injure crops, it is very important to mitigate drift from application of formulations containing mesotrione and rimsulfuron plus thifensulfuron-methyl in combination. This can be done by selecting the appropriate nozzle and ensuring optimal distances between crops. [ABSTRACT FROM AUTHOR]

Redroot (Amaranthus retroflexus L.) and smooth pigweed (A. hybridus L.) are troublesome weeds in row crops in Serbia. Both species are very competitive, hosts for pathogens and insects, produce pollen which is highly allergenic; and the most recent research reported herbicide resistance in some populations across Serbia. An integrated approach for the control of both Amaranthus species must be evaluated and presented in order to reduce their negative potential in agriculture. In this paper, 9 yr results on redroot pigweed and smooth pigweed weed control are presented. In three different experiments, weed density and biomass of redroot and smooth pigweed were recorded: a) Crop rotation, b) row spacing and time of herbicide application, c) influence of nozzles and adjuvants. The influence of crop rotation and PRE herbicide mixture, PRE and POST mixture, and impact of nozzles and adjuvants were evaluated. PRE herbicide mix of S-metolachlor and isoxaflutole influenced 98.1% and 100% efficacy in the maize (Zea mays L.) continuous and in maize rotated with winter wheat (Triticum aestivum L.), respectively. The mixture of two herbicides, applied either in PRE or POST, resulted in 100% of control of both species. Finally, similar results were obtained for nicosulfuron application with extended range (XR) or turbo TeeJet induction (TTI) nozzles, and combined with nonionic surfactant (NIS) or ammonium sulphate (AMS) adjuvants. The novelty of obtained results indicates that only holistic approach based on different weed management practices can contribute to sustainable Amaranthus control. [ABSTRACT FROM AUTHOR]

Copyright of Pesticides & Phytomedicine / Pesticidi i Fitomedicina is the property of Institute of Pesticides & Environmental Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To control weeds and cultivate maize (Zea mays L.) with higher yields, production systems have to include more efficient forms of N and appropriate herbicide treatments. The timing of N release could give maize an advantage over weeds in competition for resources, whereas cultivation at lower row spacing often decreases weed biomass. Knowledge about the different factors affecting herbicide efficiency increases the accuracy and reliability of chemical control. This study tested the weed infestation level and the development and productivity of a recently developed maize hybrid grown with the application of several integrated practices. The maize hybrid was sown with application of standard and slow‐releasing urea, with row spacing of 50 and 70 cm and treatment with either a pre‐emergence or a post‐emergence mix of herbicides. The numbers of plants of each weed species and their biomass were lower after the application of herbicides, although N form and row spacing produced no significant differences in the average weed infestation level for 3 yr. The post‐emergence herbicide treatment was more effective than the pre‐emergence treatment for weed biomass reduction and enhancing maize yield parameters. The N form did not influence any measured yield parameter, whereas the 70‐cm row spacing resulted in significantly higher harvest index and grain yield (0.45 and 9.19 Mg ha−1, respectively) than the 50‐cm spacing (0.43 and 7.36 Mg ha−1, respectively). The wider row spacing resulted in higher grain yield through its interaction with N form and herbicide treatment. [ABSTRACT FROM AUTHOR]

Plant response to herbicides is one of the most essential points in corn (Zea mays L.) production, especially in inbred lines. Weed abundance is higher in corn lines comparing to hybrids. Insufficient herbicide selectivity in lines crop can be a limiting factor for their application. Weed control today is based on Integrated Weed Management (IWM) approach, i.e. to use all possible methods and measures for weed control and better crop fitness. In this research, sensitivity of one corn inbred line (selection based on previous research) was tested to two sulfonylurea herbicides in treatments with and without foliar fertilizer. Treatments included recommended and double field doses and control (no herbicide), with and without foliar fertilizer. Herbicides and foliar fertilizer were applied as a mixture. In a 3 yr field experiment, herbicides expressed different selectivity to the tested line. The line was further tested in controlled conditions for dose-response analyses in order to determine variations in biomass and biochemical compounds levels. The double dose of foramsulfuron affected fresh matter significantly (p < 0.05) with 90% decrease, compared to control. An experiment in controlled conditions showed increased tolerance to herbicides in treatments with foliar fertilizer -- according to higher effective doses (ED10, ED50, and ED90) estimated, indicating higher plant tolerance to herbicides when foliar fertilizer was applied. In corn leaves the highest herbicide dose and foliar fertilizer induced slight reduction of concentrations of free thiol groups, soluble proteins and phytic P (to 14.1%, 9.3% and 9.9%, respectively) and increased phenolics concentration (up to 26.7%) compared to treatment without herbicide application. Obtained results indicate positive effects of foliar fertilizer when it is applied in mixture with herbicides, and foliar fertilizing should be considered as important strategy in obtaining higher yields. [ABSTRACT FROM AUTHOR]

Copyright of Zemdirbyste-Agriculture is the property of Lithuanian Research Centre for Agriculture & Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Genetika (0534-0012) is the property of Serbian Genetics Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Limitations on the available herbicide portfolio for weed control have led to weed control failures. Application techniques such as proper selection of nozzle types, adjuvants, and herbicide selection have been suggested as one of the ways to maximize efficacy. The launch of HPPD (hydroxyphenylpyruvate dioxygenase)-tolerant crops will increase HPPD herbicide applications, while effective herbicide tank mixtures might prolong herbicide resistance evolution. Therefore, a greenhouse experiment was conducted to evaluate the effects of mesotrione (MES) and rimsulfuron plus thifensulfuron-methyl (RIMTHIF) in tank mixtures with five adjuvants sprayed with three different nozzle types, XR (Extended Range), AIXR (Air Induction Extended Range), and TTI (Turbo TeeJet Induction), on weed control. Five weed species were tested: common lambsquarters (Chenopodium album L.), velvetleaf (Abutilon theophrasti Medic.), common waterhemp (Amaranthus tuberculatus (Moq.) J.D. Sauer), Palmer amaranth (Amaranthus palmeri S. Wats.), barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.), and a grain sorghum (Sorghum bicolor (L.) Moench) crop. A dose‒response study using MES and RIMTHIF was conducted to estimate the effective dose to reduce the aboveground biomass by 50% from the nontreated control (ED 50). Another study was conducted to evaluate the efficacy of MES and RIMTHIF in tank mixtures with five adjuvants (ammonium sulfate – AMS, crop oil concentrate – COC, drift reducing adjuvant – DRA, methylated seed oil – MSO, and nonionic surfactant – NIS) sprayed with three nozzle types (XR, AIXR, and TTI). The selected nozzles influenced velvetleaf, common lambsquarters, and sorghum, indicating the possibility of applying herbicides with Coarser sprays, avoiding off-target movement. Our findings suggest adjuvants are an essential factor for improving weed control over the active ingredient, up to 18.7% and 38.3% for MES and RIMTHIF, respectively. Barnyardgrass biomass reduction was greater than 98% with RIMTHIF in tank mixtures with COC and MSO compared to 65% when applied alone. Common lambsquarters had 52.1% biomass reduction when RIMTHIF was sprayed alone, while adding adjuvants to the tank-mixture resulted in biomass reduction ranging from 60.1% (COC) to 94.1% (AMS). Velvetleaf biomass reduction was 98% when the MES and RIMTHIF mixture was applied with the addition of MSO, while 87% without the adjuvant added. These results indicate that adding adjuvants in herbicide solution can improve herbicide efficacy (COC and MSO for barnyardgrass; NIS, AMS, and MSO for velvetleaf; and NIS, COC, and MSO for common lambsquaters). [Display omitted] • The efficacy of mesotrione and rimsulfuron plus thifensulfuron-methyl was tested. • The study also tested the influence of five adjuvants and three nozzle types. • Effective weed control as an alternative to commonly used herbicides. • Weed control increased using adjuvants, up to 18.7% and 38.3%. • Coarser droplets presented satisfactory weed control while reducing drift potential. [ABSTRACT FROM AUTHOR]

Copyright of Pesticides & Phytomedicine / Pesticidi i Fitomedicina is the property of Institute of Pesticides & Environmental Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crop rotation is a simple and effective part of an Integrated Weed Management (IWM) system. This approach makes it possible to rotate herbicides with different modes of action (MOA), avoiding or postponing herbicide resistance. Besides all the known advantages and benefits, it is still not widely used in maize (Zea mays L.) production. In Serbia, about 20% of total maize production is a continuous cropping. The aim of this research was to test the benefits of growing maize in crop rotation with winter wheat (Triticum vulgare L.) compared with a continuous cropping, combined with pre-emergence herbicide application. Field trials started in 2009, and five maize-winter wheat rotations have been completed. Weeds were controlled with a herbicide mixture of isoxaflutole and S-metolachlor, applied at either the full label rate or half rate, while one plot was kept weed free (manually), and one was a control. Integrating crop rotation and PRE herbicides decreased the biomass of weeds and their density by 98% and 99%, respectively. In continuous maize, perennial weeds became dominant after the first rotation. Crop rotation significantly influenced maize productive parameters, decreasing the variation in leaf area index and grain yield, increasing values with the number of cycles. The biggest differences in the analyzed parameters were observed in 2015, 2017 and 2019, indicating many positive long-term benefits of crop rotation on maize leaf area index and grain yield. Image 1 • Maize - winter wheat rotation significantly reduced weeds density and biomass. • A decreasing tendency of perennial weeds was reported in crop rotation. • Crop rotation with Isoxaflutole and S-metolachlor reduced weeds up to 99%. • In crop rotation appying 1/2 of herbicide rate could be as effective as the full rate. • Maize leaf area and grain yield were significantly higher in crop rotation. [ABSTRACT FROM AUTHOR]

Intensive weed management is required to meet the growing demands of sweet maize production. Herbicide application is inevitable in sweet maize production, while foliar fertilizer is commonly used in cropping in order to improve crop yield and quality. The effect of nicosulfuron and mesotrione, with and without foliar fertilizer, on the content of phytochemicals (i.e. carotenoids, tocopherols and free phenolic acids) in the kernels of three sweet maize hybrids was evaluated. Herbicides applied alone mainly improved the nutritive profile of the sweet maize kernel. The application of herbicides in combination with foliar fertilizer showed a high variability in the concentration of carotenoids, tocopherols and free phenolic acids. The significant change in the content of phytochemicals was induced by the applied treatments, but it is also genotype-dependent, which was also confirmed by the Principal Component Analysis. • First report of herbicides impact on free phenolic acids content in sweet maize kernel. • Assessment of the effects of herbicides plus foliar fertilizer on eleven phytochemicals. • Improved free ferulic acid and α -tocopherol content was noticed. • Applied treatments gave sweet maize higher value in terms of functional foods. [ABSTRACT FROM AUTHOR]

Susceptibility of maize inbred lines causes a need to study their response to the existing and new active ingredients of herbicides. The present study observes the effects of the application of two sulfonylurea herbicides: nicosulphuron and foramsulphuron on the content of fresh and dry matter in seedlings, as well as, on the EWRC values of eight ZP maize inbred lines during three year study. The differences in susceptibility to applied herbicides were observed among years and genotypes. During 2006, as the season with lower temperatures during the period of starting growth, the applied herbicides induced decrease of average fresh matter (about 19%) and increase of average dry matter (about 4%), compared to the control. Meanwhile, during 2007, average fresh and dry matter were varied up to ± 7%, compared to the control. It is more significant to emphasize, during 2008 fresh matter was increased up to 13%, while dry matter was lower about 1% in both applied herbicide treatments. The observed data are in agreement with negligible lower EWRC values present in 2007 and 2008, compared to 2006. It was also important to underline that most susceptible maize inbred indicated lower tolerance to foramsulphuron, through higher EWRC values, as well as increase of dry matter, which could point desiccation as one of the first signs of a stress. [ABSTRACT FROM AUTHOR]